Bump version to 5.1.7 for release

Paper 1.21.3 requires changes to placeholders and is not currently supported.

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+  - package-ecosystem: "maven"
+    directory: "/"
+    schedule:
+      interval: "monthly"

.github/workflows/automerge_dependabot.yml

@@ -0,0 +1,55 @@
+name: Auto-merge Dependabot PRs
+
+on:
+  workflow_run:
+    workflows: [ "Pull Request" ]
+    types: [ completed ]
+
+jobs:
+  merge-dependabot:
+    if: "github.actor == 'dependabot[bot]'
+      && github.event.workflow_run.event == 'pull_request'
+      && github.event.workflow_run.conclusion == 'success'"
+    runs-on: ubuntu-latest
+    steps:
+      # Note: this is directly from GitHub's example for using data from a triggering workflow:
+      # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#using-data-from-the-triggering-workflow
+      - name: 'Download artifact'
+        uses: actions/github-script@v7
+        with:
+          script: |
+            let allArtifacts = await github.rest.actions.listWorkflowRunArtifacts({
+               owner: context.repo.owner,
+               repo: context.repo.repo,
+               run_id: context.payload.workflow_run.id,
+            });
+            let matchArtifact = allArtifacts.data.artifacts.filter((artifact) => {
+              return artifact.name == "pr_number"
+            })[0];
+            let download = await github.rest.actions.downloadArtifact({
+               owner: context.repo.owner,
+               repo: context.repo.repo,
+               artifact_id: matchArtifact.id,
+               archive_format: 'zip',
+            });
+            let fs = require('fs');
+            fs.writeFileSync(`${process.env.GITHUB_WORKSPACE}/pr_number.zip`, Buffer.from(download.data));
+
+      # This might be a useless use of cat, but I'm not sure what shell Actions is going to be running.
+      - name: Add Pull Number Variable
+        run: |-
+          unzip pr_number.zip
+          echo "PR_NUMBER=$(cat pr_number)" >> "$GITHUB_ENV"
+
+      - name: Approve
+        uses: hmarr/auto-approve-action@v4.0.0
+        with:
+          github-token: "${{ secrets.GITHUB_TOKEN }}"
+          pull-request-number: "${{ env.PR_NUMBER }}"
+      - name: Merge
+        uses: pascalgn/automerge-action@v0.16.4
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+          MERGE_LABELS: "dependencies,java"
+          MERGE_METHOD: "squash"
+          PULL_REQUEST: "${{ env.PR_NUMBER }}"

.github/workflows/ci.yml

@@ -0,0 +1,40 @@
+name: OpenInv CI
+
+on:
+  push:
+    branches:
+      - 'master'
+    tags-ignore:
+      - '**'
+    paths-ignore:
+      - resource-pack/openinv-legibility-pack/**
+  # Enable running CI via other Actions, i.e. for drafting releases and handling PRs.
+  workflow_call:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '21'
+
+      # TODO convert to a Gradle plugin later for portability
+      - name: Install Spigot dependency
+        run: ./scripts/install_spigot.sh 1.21.4
+
+      - uses: gradle/actions/setup-gradle@v4
+
+      - name: Build with Gradle
+        run: ./gradlew build
+
+      # Upload artifacts
+      - name: Upload Distributable Jar
+        id: upload-final
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: ./dist/*

.github/workflows/draft_release.yml

@@ -0,0 +1,42 @@
+name: Draft Github Release
+
+on:
+  push:
+    tags:
+      - '**'
+
+jobs:
+  run-ci:
+    uses: Jikoo/OpenInv/.github/workflows/ci.yml@master
+  draft-release:
+    needs: [ run-ci ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download build
+        uses: actions/download-artifact@v4
+        with:
+          name: dist
+          path: dist
+
+      - name: Create Release
+        id: create-release
+        uses: softprops/action-gh-release@v2.2.1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          name: ${{ env.VERSIONED_NAME }}
+          # May actually want to manually specify Paper versions all the time; they won't all
+          # need to be specified in code thanks to Mojang-mapped server internals.
+          # A bit annoying, but not terribly so.
+          # Instead, fetch min and max (which will also be Spigot version) and manually list intermediate versions?
+          body: |-
+            ## Supported server versions
+            ### Paper
+            TODO COMMA-SEPARATED VERSIONS
+            ### Spigot
+            TODO VERSION
+            
+            TODO HELLO HUMAN, PRESS THE GENERATE CHANGELOG BUTTON PLEASE.
+          draft: true
+          prerelease: false
+          files: ./dist/**

.github/workflows/external_release.yml

@@ -0,0 +1,37 @@
+name: Release to CurseForge
+
+on:
+  release:
+    types: [ released ]
+
+jobs:
+  curseforge_release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Fetch Github Release Asset
+        uses: dsaltares/fetch-gh-release-asset@1.1.2
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          version: ${{ github.event.release.id }}
+          file: OpenInv.jar
+
+      - name: Set CurseForge Variables
+        run: . scripts/set_curseforge_env.sh "${{ github.event.release.body }}"
+
+      - name: Create CurseForge Release
+        uses: itsmeow/curseforge-upload@v3
+        with:
+          token: "${{ secrets.CURSEFORGE_TOKEN }}"
+          project_id: 31432
+          game_endpoint: minecraft
+          file_path: ./OpenInv.jar
+          display_name: "${{ github.event.release.name }}"
+          game_versions: "${{ env.CURSEFORGE_MINECRAFT_VERSIONS }}"
+          release_type: release
+          changelog_type: markdown
+          changelog: "${{ github.event.release.body }}"

.github/workflows/pull_request.yml

@@ -0,0 +1,22 @@
+name: Pull Request
+
+on:
+  pull_request:
+
+jobs:
+  run-ci:
+    uses: Jikoo/OpenInv/.github/workflows/ci.yml@master
+  store-dependabot-pr-data:
+    if: "github.actor == 'dependabot[bot]' && github.event_name == 'pull_request'"
+    runs-on: ubuntu-latest
+    steps:
+      # Note: this is directly from GitHub's example for using data from a triggering workflow:
+      # https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#using-data-from-the-triggering-workflow
+      - name: Store Pull Number
+        run: |
+          mkdir -p ./pr
+          echo ${{ github.event.number }} > ./pr/pr_number
+      - uses: actions/upload-artifact@v4
+        with:
+          name: pr_number
+          path: pr/

.github/workflows/resource_pack_ci.yml

@@ -0,0 +1,24 @@
+name: Resource Pack CI
+
+on:
+  push:
+    branches:
+      - 'master'
+    tags-ignore:
+      - '**'
+    paths:
+      - resource-pack/openinv-legibility-pack/**
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Build resource pack
+        id: upload-resource-pack
+        uses: actions/upload-artifact@v4
+        with:
+          name: openinv-legibility-pack
+          path: ./resource-pack/openinv-legibility-pack/
+          compression-level: 9

.gitignore

@@ -0,0 +1,13 @@
+**/.settings
+**/.project
+**/.classpath
+**/.idea/
+**/.gradle/
+**.iml
+**/target/
+**/bin/
+**/out/
+**/build/
+**/dist/
+**/dependency-reduced-pom.xml
+**/pom.xml.versionsBackup

.settings/org.eclipse.ltk.core.refactoring.prefs

@@ -1,3 +0,0 @@
-#Wed Jun 01 17:38:54 EDT 2011
-eclipse.preferences.version=1
-org.eclipse.ltk.core.refactoring.enable.project.refactoring.history=false

README

@@ -1,13 +0,0 @@
-Copyright (C) 2011-2014 lishid.  All rights reserved.
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation,  version 3.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program. If not, see <http://www.gnu.org/licenses/>.

README.MD

@@ -0,0 +1,54 @@
+## About
+OpenInv is a [Bukkit plugin](https://dev.bukkit.org/projects/openinv) which allows users to open and edit anyone's inventory or ender chest - online or not!
+
+## Features
+- **OpenInv**: Open anyone's inventory, even if they're offline.
+  - Read-only mode! Don't grant edit permission.
+  - Cross-world support! Allow access only from the same world.
+  - No duplicate slots! Only armor is accessible when opening self (if allowed at all)!
+  - Drop items as the player! Place items in the dropper slot in the bottom right. Can be disabled via permission!
+  - Allow any item in armor slots! Configurable via permission.
+- **OpenEnder**: Open anyone's ender chest, even if they're offline.
+  - Allow access only to own ender chest! Don't grant permission to open others.
+  - Read-only mode! Don't grant edit permission.
+  - Cross-world support! Allow access only from the same world.
+- **SilentContainer**: Open containers without displaying an animation or making sound.
+- **AnyContainer**: Open containers, even if blocked by ocelots or blocks.
+
+## Commands
+See [the wiki](https://github.com/Jikoo/OpenInv/wiki/Commands).
+
+## Permissions
+See [the wiki](https://github.com/Jikoo/OpenInv/wiki/Permissions)
+
+## For Developers
+
+### As a Dependency
+The OpenInv API is available via [JitPack](https://jitpack.io/).
+```xml
+  <repositories>
+    <repository>
+      <id>jitpack.io</id>
+      <url>https://jitpack.io</url>
+    </repository>
+  </repositories>
+```
+```xml
+  <dependencies>
+    <dependency>
+      <groupId>com.github.Jikoo</groupId>
+      <artifactId>OpenInv</artifactId>
+      <version>${openinv.version}</version>
+    </dependency>
+  </dependencies>
+```
+Note that since JitPack only builds the API now, the "full" OpenInv jar on JitPack is actually the openinvapi artifact. This is a change from previous dependency declaration that I hope to revert.
+
+### Compilation
+To compile, the relevant Spigot jar must be installed in the local repository.
+As OpenInv is compiled against Mojang's mappings, you must run BuildTools with the `--remapped` argument:  
+`java -jar BuildTools.jar --remapped --rev $serverVersion`  
+`$serverVersion` is the version of the server, i.e. `1.21.4`
+
+Once Spigot is installed, execute the gradle wrapper:  
+`./gradlew build`

addon/togglepersist/build.gradle.kts

@@ -0,0 +1,21 @@
+plugins {
+  `openinv-base`
+}
+
+dependencies {
+  implementation(project(":openinvapi"))
+}
+
+tasks.processResources {
+  expand("version" to version)
+}
+
+tasks.register<Copy>("distributeAddons") {
+  into(rootProject.layout.projectDirectory.dir("dist"))
+  from(tasks.jar)
+  rename("openinvtogglepersist.*\\.jar", "OITogglePersist.jar")
+}
+
+tasks.assemble {
+  dependsOn(tasks.named("distributeAddons"))
+}

addon/togglepersist/src/main/java/com/github/jikoo/openinv/togglepersist/TogglePersist.java

@@ -0,0 +1,143 @@
+package com.github.jikoo.openinv.togglepersist;
+
+import com.google.errorprone.annotations.Keep;
+import com.lishid.openinv.event.PlayerToggledEvent;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import com.lishid.openinv.util.setting.PlayerToggles;
+import org.bukkit.configuration.Configuration;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import java.util.logging.Level;
+
+public class TogglePersist extends JavaPlugin implements Listener {
+
+  private final Map<UUID, Set<String>> enabledToggles = new HashMap<>();
+
+  @Override
+  public void onEnable() {
+    getServer().getPluginManager().registerEvents(this, this);
+
+    File file = new File(getDataFolder(), "toggles.yml");
+
+    // If there's no save file, there's nothing to load.
+    if (!file.exists()) {
+      return;
+    }
+
+    Configuration loaded = YamlConfiguration.loadConfiguration(file);
+
+    // For each toggle, enable loaded players.
+    for (String toggleName : loaded.getKeys(false)) {
+      PlayerToggle toggle = PlayerToggles.get(toggleName);
+      // Ensure toggle exists.
+      if (toggle == null) {
+        continue;
+      }
+
+      for (String idString : loaded.getStringList(toggleName)) {
+        // Ensure valid UUID.
+        UUID uuid;
+        try {
+          uuid = UUID.fromString(idString);
+        } catch (IllegalArgumentException e) {
+          continue;
+        }
+
+        // Track that toggle is enabled.
+        set(uuid, toggleName);
+      }
+    }
+  }
+
+  private void set(UUID playerId, String toggleName) {
+    enabledToggles.compute(playerId, (uuid, toggles) -> {
+      if (toggles == null) {
+        toggles = new HashSet<>();
+      }
+      toggles.add(toggleName);
+      return toggles;
+    });
+  }
+
+  @Override
+  public void onDisable() {
+    Map<String, List<String>> converted = getSaveData();
+
+    YamlConfiguration data = new YamlConfiguration();
+    for (Map.Entry<String, List<String>> playerToggle : converted.entrySet()) {
+      data.set(playerToggle.getKey(), playerToggle.getValue());
+    }
+
+    File file = new File(getDataFolder(), "toggles.yml");
+    try {
+      data.save(file);
+    } catch (IOException e) {
+      getLogger().log(Level.SEVERE, "Unable to save player toggle states", e);
+    }
+  }
+
+  private @NotNull Map<String, List<String>> getSaveData() {
+    Map<String, List<String>> converted = new HashMap<>();
+
+    for (Map.Entry<UUID, Set<String>> playerToggles : enabledToggles.entrySet()) {
+      String idString = playerToggles.getKey().toString();
+      for (String toggleName : playerToggles.getValue()) {
+        // Add player ID to listing for each enabled toggle.
+        converted.compute(toggleName, (name, ids) -> {
+          if (ids == null) {
+            ids = new ArrayList<>();
+          }
+          ids.add(idString);
+          return ids;
+        });
+      }
+    }
+    return converted;
+  }
+
+  @Keep
+  @EventHandler
+  private void onPlayerJoin(@NotNull PlayerJoinEvent event) {
+    UUID playerId = event.getPlayer().getUniqueId();
+    Set<String> toggleNames = enabledToggles.get(playerId);
+
+    if (toggleNames == null) {
+      return;
+    }
+
+    for (String toggleName : toggleNames) {
+      PlayerToggle toggle = PlayerToggles.get(toggleName);
+      if (toggle != null) {
+        toggle.set(playerId, true);
+      }
+    }
+  }
+
+  @Keep
+  @EventHandler
+  private void onToggleSet(@NotNull PlayerToggledEvent event) {
+    if (event.isEnabled()) {
+      set(event.getPlayerId(), event.getToggle().getName());
+    } else {
+      enabledToggles.computeIfPresent(event.getPlayerId(), (uuid, toggles) -> {
+        toggles.remove(event.getToggle().getName());
+        return toggles.isEmpty() ? null : toggles;
+      });
+    }
+  }
+
+}

addon/togglepersist/src/main/resources/plugin.yml

@@ -0,0 +1,7 @@
+name: OITogglePersist
+main: com.github.jikoo.openinv.togglepersist.TogglePersist
+version: ${version}
+author: Jikoo
+description: An OpenInv addon allowing /anycontainer and /silentcontainer to persist across sessions.
+api-version: "1.20"
+depend: [ OpenInv ]

api/build.gradle.kts

@@ -0,0 +1,13 @@
+plugins {
+  `openinv-base`
+  `maven-publish`
+}
+
+publishing {
+  publications {
+    create<MavenPublication>("jitpack") {
+      groupId = "com.github.Jikoo.OpenInv"
+      artifactId = "openinvapi"
+    }
+  }
+}

api/src/main/java/com/lishid/openinv/IOpenInv.java

@@ -0,0 +1,185 @@
+/*
+ * Copyright (C) 2011-2023 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv;
+
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import org.bukkit.Bukkit;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.UUID;
+import java.util.logging.Logger;
+
+/**
+ * Interface defining behavior for the OpenInv plugin.
+ */
+public interface IOpenInv {
+
+    /**
+     * Check if the server version is supported by OpenInv.
+     *
+     * @return true if the server version is supported
+     */
+    boolean isSupportedVersion();
+
+    /**
+     * Check the configuration value for whether OpenInv saves player data when unloading players. This is exclusively
+     * for users who do not allow editing of inventories, only viewing, and wish to prevent any possibility of bugs such
+     * as lishid#40. If true, OpenInv will not ever save any edits made to players.
+     *
+     * @return false unless configured otherwise
+     */
+    boolean disableSaving();
+
+    /**
+     * Check the configuration value for whether OpenInv allows offline access. If true, OpenInv will not load or allow
+     * modification of players while they are not online. This does not prevent other plugins from using existing loaded
+     * players who have gone offline.
+     *
+     * @return false unless configured otherwise
+     * @since 4.2.0
+     */
+    boolean disableOfflineAccess();
+
+    /**
+     * Check the configuration value for whether OpenInv uses history for opening commands. If false, OpenInv will use
+     * the previous parameterized search when no parameters are provided.
+     *
+     * @return false unless configured otherwise
+     * @since 4.3.0
+     */
+    boolean noArgsOpensSelf();
+
+    /**
+     * Get the active {@link IAnySilentContainer} implementation.
+     *
+     * @return the active implementation for the server version
+     * @throws IllegalStateException if the server version is unsupported
+     */
+    @NotNull IAnySilentContainer getAnySilentContainer();
+
+    /**
+     * Get whether a user has AnyContainer mode enabled.
+     *
+     * @param offline the user to obtain the state of
+     * @return true if AnyContainer mode is enabled
+     */
+    boolean getAnyContainerStatus(@NotNull OfflinePlayer offline);
+
+    /**
+     * Set whether a user has AnyContainer mode enabled.
+     *
+     * @param offline the user to set the state of
+     * @param status the state of the mode
+     */
+    void setAnyContainerStatus(@NotNull OfflinePlayer offline, boolean status);
+
+    /**
+     * Get whether a user has SilentContainer mode enabled.
+     *
+     * @param offline the user to obtain the state of
+     * @return true if SilentContainer mode is enabled
+     */
+    boolean getSilentContainerStatus(@NotNull OfflinePlayer offline);
+
+    /**
+     * Set whether a user has SilentContainer mode enabled.
+     *
+     * @param offline the user to set the state of
+     * @param status the state of the mode
+     */
+    void setSilentContainerStatus(@NotNull OfflinePlayer offline, boolean status);
+
+    /**
+     * Get an {@link ISpecialEnderChest} for a user.
+     *
+     * @param player the {@link Player} owning the inventory
+     * @param online whether the owner is currently online
+     * @return the created inventory
+     * @throws IllegalStateException if the server version is unsupported
+     * @throws InstantiationException if there was an issue creating the inventory
+     */
+    @NotNull ISpecialEnderChest getSpecialEnderChest(@NotNull Player player, boolean online) throws InstantiationException;
+
+    /**
+     * Get an {@link ISpecialPlayerInventory} for a user.
+     *
+     * @param player the {@link Player} owning the inventory
+     * @param online whether the owner is currently online
+     * @return the created inventory
+     * @throws IllegalStateException if the server version is unsupported
+     * @throws InstantiationException if there was an issue creating the inventory
+     */
+    @NotNull ISpecialPlayerInventory getSpecialInventory(@NotNull Player player, boolean online) throws InstantiationException;
+
+    /**
+     * Open an {@link ISpecialInventory} for a {@link Player}.
+     *
+     * @param player the viewer
+     * @param inventory the inventory to open
+     * @return the resulting {@link InventoryView}
+     */
+    @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory);
+
+    /**
+     * Check if a {@link Player} is currently loaded by OpenInv.
+     *
+     * @param playerUuid the {@link UUID} of the {@code Player}
+     * @return whether the {@code Player} is loaded
+     * @since 4.2.0
+     */
+    boolean isPlayerLoaded(@NotNull UUID playerUuid);
+
+    /**
+     * Load a {@link Player} from an {@link OfflinePlayer}. If the user has not played before or the default world for
+     * the server is not loaded, this will return {@code null}.
+     *
+     * @param offline the {@code OfflinePlayer} to load a {@code Player} for
+     * @return the loaded {@code Player}
+     * @throws IllegalStateException if the server version is unsupported
+     */
+    @Nullable Player loadPlayer(@NotNull final OfflinePlayer offline);
+
+    /**
+     * Match an existing {@link OfflinePlayer}. If the name is a {@link UUID#toString() UUID string}, this will only
+     * return the user if they have actually played on the server before, unlike {@link Bukkit#getOfflinePlayer(UUID)}.
+     *
+     * <p>This method is potentially very heavily blocking. It should not ever be called on the
+     * main thread, and if it is, a stack trace will be displayed alerting server owners to the
+     * call.
+     *
+     * @param name the string to match
+     * @return the user with the closest matching name
+     */
+    @Nullable OfflinePlayer matchPlayer(@NotNull String name);
+
+    /**
+     * Forcibly close inventories of and unload any cached data for a user.
+     *
+     * @param offline the {@link OfflinePlayer} to unload
+     */
+    void unload(@NotNull OfflinePlayer offline);
+
+    Logger getLogger();
+
+}

api/src/main/java/com/lishid/openinv/event/OpenPlayerSaveEvent.java

@@ -0,0 +1,56 @@
+package com.lishid.openinv.event;
+
+import com.google.errorprone.annotations.RestrictedApi;
+import com.lishid.openinv.internal.ISpecialInventory;
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Event fired before OpenInv saves a player's data when closing an {@link ISpecialInventory}.
+ */
+public class OpenPlayerSaveEvent extends PlayerSaveEvent {
+
+  private static final HandlerList HANDLERS = new HandlerList();
+
+  private final ISpecialInventory inventory;
+
+  /**
+   * Construct a new {@code OpenPlayerSaveEvent}.
+   *
+   * <p>The constructor is not considered part of the API, and may be subject to change.</p>
+   *
+   * @param player the player to be saved
+   * @param inventory the {@link ISpecialInventory} being closed
+   */
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/OpenEvents.java")
+  @ApiStatus.Internal
+  OpenPlayerSaveEvent(@NotNull Player player, @NotNull ISpecialInventory inventory) {
+    super(player);
+    this.inventory = inventory;
+  }
+
+  /**
+   * Get the {@link ISpecialInventory} that triggered the save by being closed.
+   *
+   * @return the special inventory
+   */
+  public @NotNull ISpecialInventory getInventory() {
+    return inventory;
+  }
+
+  @NotNull
+  @Override
+  public HandlerList getHandlers() {
+    return HANDLERS;
+  }
+
+  public static HandlerList getHandlerList() {
+    return HANDLERS;
+  }
+
+}

api/src/main/java/com/lishid/openinv/event/PlayerSaveEvent.java

@@ -0,0 +1,67 @@
+package com.lishid.openinv.event;
+
+
+import com.google.errorprone.annotations.RestrictedApi;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Event fired before a {@link Player} loaded via OpenInv is saved.
+ */
+public class PlayerSaveEvent extends PlayerEvent implements Cancellable {
+
+  private static final HandlerList HANDLERS = new HandlerList();
+
+  private boolean cancelled = false;
+
+  /**
+   * Construct a new {@code PlayerSaveEvent}.
+   *
+   * <p>The constructor is not considered part of the API, and may be subject to change.</p>
+   *
+   * @param player the player to be saved
+   */
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/(OpenPlayerSaveEvent|OpenEvents).java")
+  @ApiStatus.Internal
+  PlayerSaveEvent(@NotNull Player player) {
+    super(player);
+  }
+
+  /**
+   * Get whether the event is cancelled.
+   *
+   * @return true if the event is cancelled
+   */
+  @Override
+  public boolean isCancelled() {
+    return cancelled;
+  }
+
+  /**
+   * Set whether the event is cancelled.
+   *
+   * @param cancel whether the event is cancelled
+   */
+  @Override
+  public void setCancelled(boolean cancel) {
+    this.cancelled = cancel;
+  }
+
+  @NotNull
+  @Override
+  public HandlerList getHandlers() {
+    return HANDLERS;
+  }
+
+  public static HandlerList getHandlerList() {
+    return HANDLERS;
+  }
+
+}

api/src/main/java/com/lishid/openinv/event/PlayerToggledEvent.java

@@ -0,0 +1,71 @@
+package com.lishid.openinv.event;
+
+import com.google.errorprone.annotations.RestrictedApi;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.UUID;
+
+/**
+ * Event fired after OpenInv modifies a toggleable setting for a player.
+ */
+public class PlayerToggledEvent extends Event {
+
+  private static final HandlerList HANDLERS = new HandlerList();
+
+  private final @NotNull PlayerToggle toggle;
+  private final @NotNull UUID uuid;
+  private final boolean enabled;
+
+  @RestrictedApi(
+      explanation = "Constructor is not considered part of the API and may be subject to change.",
+      link = "",
+      allowedOnPath = ".*/com/lishid/openinv/event/OpenEvents.java")
+  @ApiStatus.Internal
+  PlayerToggledEvent(@NotNull PlayerToggle toggle, @NotNull UUID uuid, boolean enabled) {
+    this.toggle = toggle;
+    this.uuid = uuid;
+    this.enabled = enabled;
+  }
+
+  /**
+   * Get the {@link PlayerToggle} affected.
+   *
+   * @return the toggle
+   */
+  public @NotNull PlayerToggle getToggle() {
+    return toggle;
+  }
+
+  /**
+   * Get the {@link UUID} of the player whose setting was changed.
+   *
+   * @return the player ID
+   */
+  public @NotNull UUID getPlayerId() {
+    return uuid;
+  }
+
+  /**
+   * Get whether the toggle is enabled.
+   *
+   * @return true if the toggle is enabled
+   */
+  public boolean isEnabled() {
+    return enabled;
+  }
+
+  @NotNull
+  @Override
+  public HandlerList getHandlers() {
+    return HANDLERS;
+  }
+
+  public static HandlerList getHandlerList() {
+    return HANDLERS;
+  }
+
+}

api/src/main/java/com/lishid/openinv/internal/IAnySilentContainer.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2011-2023 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.internal;
+
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.block.BlockState;
+import org.bukkit.block.EnderChest;
+import org.bukkit.block.data.Directional;
+import org.bukkit.entity.Cat;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryHolder;
+import org.bukkit.util.BoundingBox;
+import org.jetbrains.annotations.NotNull;
+
+public interface IAnySilentContainer {
+
+    /**
+     * Forcibly open the container at the given coordinates for the Player. This will open blocked containers! Be sure
+     * to check {@link #isAnyContainerNeeded(Block)} first if that is not desirable.
+     *
+     * @param player the {@link Player} opening the container
+     * @param silent whether the container's noise is to be silenced
+     * @param block  the {@link Block} of the container
+     * @return true if the container can be opened
+     */
+    boolean activateContainer(@NotNull Player player, boolean silent, @NotNull Block block);
+
+    /**
+     * Perform operations required to close the current container silently.
+     *
+     * @param player the {@link Player} closing a container
+     */
+    void deactivateContainer(@NotNull Player player);
+
+    /**
+     * Check if the container at the given coordinates is blocked.
+     *
+     * @param block the {@link Block} of the container
+     * @return true if the container is blocked
+     */
+    boolean isAnyContainerNeeded(@NotNull Block block);
+
+    /**
+     * Check if a shulker box block cannot be opened under ordinary circumstances.
+     *
+     * @param shulkerBox the shulker box block
+     * @return whether the container is blocked
+     */
+    default boolean isShulkerBlocked(@NotNull Block shulkerBox) {
+        Directional directional = (Directional) shulkerBox.getBlockData();
+        BlockFace facing = directional.getFacing();
+        // Construct a new 1-block bounding box at the origin.
+        BoundingBox box = new BoundingBox(0, 0, 0, 1, 1, 1);
+        // Expand the box in the direction the shulker will open.
+        box.expand(facing, 0.5);
+        // Move the box away from the origin by a block so only the expansion intersects with a box around the origin.
+        box.shift(facing.getOppositeFace().getDirection());
+        // Check if the relative block's collision shape (which will be at the origin) intersects with the expanded box.
+        return shulkerBox.getRelative(facing).getCollisionShape().overlaps(box);
+    }
+
+    /**
+     * Check if a chest cannot be opened under ordinary circumstances.
+     *
+     * @param chest the chest block
+     * @return whether the container is blocked
+     */
+    default boolean isChestBlocked(@NotNull Block chest) {
+        org.bukkit.block.Block relative = chest.getRelative(0, 1, 0);
+        return relative.getType().isOccluding()
+                || !chest.getWorld().getNearbyEntities(BoundingBox.of(relative), Cat.class::isInstance).isEmpty();
+    }
+
+    /**
+     * Check if the given {@link Block} is a container which can be unblocked or silenced.
+     *
+     * @param block the potential container
+     * @return true if the type is a supported container
+     */
+    boolean isAnySilentContainer(@NotNull Block block);
+
+    /**
+     * Check if the given {@link BlockState} is a container which can be unblocked or silenced.
+     *
+     * @param blockState the potential container
+     * @return true if the type is a supported container
+     */
+    default boolean isAnySilentContainer(@NotNull BlockState blockState) {
+        return (blockState instanceof InventoryHolder holder && isAnySilentContainer(holder))
+                || blockState instanceof EnderChest;
+    }
+
+    /**
+     * Check if the given {@link InventoryHolder} is a container which can be unblocked or silenced.
+     *
+     * @param holder the potential container
+     * @return true if the type is a supported container
+     */
+    default boolean isAnySilentContainer(@NotNull InventoryHolder holder) {
+        return holder instanceof org.bukkit.block.EnderChest
+                || holder instanceof org.bukkit.block.Chest
+                || holder instanceof org.bukkit.block.DoubleChest
+                || holder instanceof org.bukkit.block.ShulkerBox
+                || holder instanceof org.bukkit.block.Barrel;
+    }
+
+}

api/src/main/java/com/lishid/openinv/internal/ISpecialEnderChest.java

@@ -1,31 +1,32 @@
-/*
- * Copyright (C) 2011-2014 lishid.  All rights reserved.
- * 
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation,  version 3.
- * 
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- * 
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.internal;
-
-import org.bukkit.entity.Player;
-import org.bukkit.inventory.Inventory;
-
-public interface ISpecialEnderChest {
-    public Inventory getBukkitInventory();
-
-    public void InventoryRemovalCheck();
-
-    public void PlayerGoOnline(Player p);
-
-    public void PlayerGoOffline();
-
-}
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.internal;
+
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * An {@link ISpecialInventory} representing an ender chest.
+ */
+public interface ISpecialEnderChest extends ISpecialInventory {
+
+  @Override
+  default @NotNull InventoryType getBukkitType() {
+    return InventoryType.ENDER_CHEST;
+  }
+
+}

api/src/main/java/com/lishid/openinv/internal/ISpecialInventory.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.internal;
+
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Interface defining behavior for special inventories backed by other inventories' content listings.
+ */
+public interface ISpecialInventory {
+
+    /**
+     * Get the {@link Inventory} associated with this {@code ISpecialInventory}.
+     *
+     * @return the Bukkit inventory
+     */
+    @NotNull Inventory getBukkitInventory();
+
+    /**
+     * Get the {@link InventoryType} corresponding to this {@code ISpecialInventory}.
+     *
+     * @return the type of Bukkit inventory
+     */
+    @NotNull InventoryType getBukkitType();
+
+    /**
+     * Set the owning {@link Player} instance to a newly-joined user.
+     *
+     * @param player the user coming online
+     */
+    void setPlayerOnline(@NotNull Player player);
+
+    /**
+     * Mark the owner of the inventory offline.
+     */
+    void setPlayerOffline();
+
+    /**
+     * Get whether the inventory is being viewed by any users.
+     *
+     * @return true if the inventory is being viewed
+     */
+    default boolean isInUse() {
+        return !getBukkitInventory().getViewers().isEmpty();
+    }
+
+    /**
+     * Get the {@link Player} who owns the inventory.
+     *
+     * @return the {@link HumanEntity} who owns the inventory
+     */
+    @NotNull HumanEntity getPlayer();
+
+}

api/src/main/java/com/lishid/openinv/internal/ISpecialPlayerInventory.java

@@ -1,30 +1,32 @@
-/*
- * Copyright (C) 2011-2014 lishid.  All rights reserved.
- * 
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation,  version 3.
- * 
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- * 
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.internal;
-
-import org.bukkit.entity.Player;
-import org.bukkit.inventory.Inventory;
-
-public interface ISpecialPlayerInventory {
-    public Inventory getBukkitInventory();
-
-    public void InventoryRemovalCheck();
-
-    public void PlayerGoOnline(Player p);
-
-    public void PlayerGoOffline();
-}
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.internal;
+
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * An {@link ISpecialInventory} representing a player inventory.
+ */
+public interface ISpecialPlayerInventory extends ISpecialInventory {
+
+    @Override
+    default @NotNull InventoryType getBukkitType() {
+        return InventoryType.PLAYER;
+    }
+
+}

api/src/main/java/com/lishid/openinv/util/InventoryAccess.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util;
+
+import com.google.errorprone.annotations.RestrictedApi;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.function.BiFunction;
+
+public final class InventoryAccess {
+
+    private static @Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, ISpecialInventory> provider;
+
+    public static boolean isUsable() {
+        return provider != null;
+    }
+
+    /**
+     * Check if an {@link Inventory} is an {@link ISpecialPlayerInventory} implementation.
+     *
+     * @param inventory the Bukkit inventory
+     * @return true if backed by the correct implementation
+     */
+    public static boolean isPlayerInventory(@NotNull Inventory inventory) {
+        return getPlayerInventory(inventory) != null;
+    }
+
+    /**
+     * Get the {@link ISpecialPlayerInventory} backing an {@link Inventory}. Returns {@code null} if the inventory is
+     * not backed by the correct class.
+     *
+     * @param inventory the Bukkit inventory
+     * @return the backing implementation if available
+     */
+    public static @Nullable ISpecialPlayerInventory getPlayerInventory(@NotNull Inventory inventory) {
+        return provider == null ? null : (ISpecialPlayerInventory) provider.apply(inventory, ISpecialPlayerInventory.class);
+    }
+
+    /**
+     * Check if an {@link Inventory} is an {@link ISpecialEnderChest} implementation.
+     *
+     * @param inventory the Bukkit inventory
+     * @return true if backed by the correct implementation
+     */
+    public static boolean isEnderChest(@NotNull Inventory inventory) {
+        return getEnderChest(inventory) != null;
+    }
+
+    /**
+     * Get the {@link ISpecialEnderChest} backing an {@link Inventory}. Returns {@code null} if the inventory is
+     * not backed by the correct class.
+     *
+     * @param inventory the Bukkit inventory
+     * @return the backing implementation if available
+     */
+    public static @Nullable ISpecialEnderChest getEnderChest(@NotNull Inventory inventory) {
+        return provider == null ? null : (ISpecialEnderChest) provider.apply(inventory, ISpecialEnderChest.class);
+    }
+
+    /**
+     * Get a {@link ISpecialInventory} backing an {@link Inventory}. Returns {@code null} if the inventory is not backed
+     * by the correct class.
+     *
+     * @param inventory the Bukkit inventory
+     * @return the backing implementation if available
+     */
+    public static @Nullable ISpecialInventory getInventory(@NotNull Inventory inventory) {
+        return provider == null ? null : provider.apply(inventory, ISpecialInventory.class);
+    }
+
+    @RestrictedApi(
+        explanation = "Not part of the API.",
+        link = "",
+        allowedOnPath = ".*/com/lishid/openinv/util/InternalAccessor.java")
+    @ApiStatus.Internal
+    static void setProvider(@Nullable BiFunction<Inventory, Class<? extends ISpecialInventory>, ISpecialInventory> provider) {
+        InventoryAccess.provider = provider;
+    }
+
+    private InventoryAccess() {
+        throw new IllegalStateException("Cannot create instance of utility class.");
+    }
+
+}

api/src/main/java/com/lishid/openinv/util/setting/PlayerToggle.java

@@ -0,0 +1,36 @@
+package com.lishid.openinv.util.setting;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.UUID;
+
+/**
+ * A per-player setting that may be enabled or disabled.
+ */
+public interface PlayerToggle {
+
+  /**
+   * Get the name of the setting.
+   *
+   * @return the setting name
+   */
+  @NotNull String getName();
+
+  /**
+   * Get the state of the toggle for a particular player ID.
+   *
+   * @param uuid the player ID
+   * @return true if the setting is enabled
+   */
+  boolean is(@NotNull UUID uuid);
+
+  /**
+   * Set the state of the toggle for a particular player ID.
+   *
+   * @param uuid the player ID
+   * @param enabled whether the setting is enabled
+   * @return true if the setting changed as a result of being set
+   */
+  boolean set(@NotNull UUID uuid, boolean enabled);
+
+}

api/src/main/java/com/lishid/openinv/util/setting/PlayerToggles.java

@@ -0,0 +1,106 @@
+package com.lishid.openinv.util.setting;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.UnmodifiableView;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * Utility class containing all of OpenInv's {@link PlayerToggle PlayerToggles}.
+ */
+public final class PlayerToggles {
+
+  private static final Map<String, PlayerToggle> TOGGLES = new HashMap<>();
+  private static final PlayerToggle ANY = add(new MemoryToggle("AnyContainer"));
+  private static final PlayerToggle SILENT = add(new MemoryToggle("SilentContainer"));
+
+  /**
+   * Get the AnyContainer toggle.
+   *
+   * @return the AnyContainer toggle
+   */
+  public static @NotNull PlayerToggle any() {
+    return ANY;
+  }
+
+  /**
+   * Get the SilentContainer toggle.
+   *
+   * @return the SilentContainer toggle
+   */
+  public static @NotNull PlayerToggle silent() {
+    return SILENT;
+  }
+
+  /**
+   * Get a toggle by name.
+   *
+   * @param toggleName the name of the toggle
+   * @return the toggle, or null if no such toggle exists.
+   */
+  public static @Nullable PlayerToggle get(@NotNull String toggleName) {
+    PlayerToggle toggle = TOGGLES.get(toggleName);
+    if (toggle == null) {
+      toggle = TOGGLES.get(toggleName.toLowerCase(Locale.ENGLISH));
+    }
+    return toggle;
+  }
+
+  /**
+   * Get an unmodifable view of all toggles available.
+   *
+   * @return a view of all toggles available
+   */
+  public static @UnmodifiableView @NotNull Collection<PlayerToggle> get() {
+    return Collections.unmodifiableCollection(TOGGLES.values());
+  }
+
+  private static @NotNull PlayerToggle add(@NotNull PlayerToggle toggle) {
+    TOGGLES.put(toggle.getName().toLowerCase(Locale.ENGLISH), toggle);
+    return toggle;
+  }
+
+  private PlayerToggles() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+  private static class MemoryToggle implements PlayerToggle {
+
+    private final @NotNull Set<UUID> enabled;
+    private final @NotNull String name;
+
+    private MemoryToggle(@NotNull String name) {
+      enabled = new HashSet<>();
+      this.name = name;
+    }
+
+    @Override
+    public @NotNull String getName() {
+      return this.name;
+    }
+
+    @Override
+    public boolean is(@NotNull UUID uuid) {
+      return enabled.contains(uuid);
+    }
+
+    @Override
+    public boolean set(@NotNull UUID uuid, boolean enabled) {
+      if (enabled) {
+        return this.enabled.add(uuid);
+      } else {
+        return this.enabled.remove(uuid);
+      }
+    }
+
+  }
+
+}

build.gradle.kts

@@ -0,0 +1,24 @@
+plugins {
+  `java-library`
+  alias(libs.plugins.paperweight) apply false
+  alias(libs.plugins.shadow) apply false
+}
+
+repositories {
+  maven("https://repo.papermc.io/repository/maven-public/")
+}
+
+// Allow submodules to target higher Java release versions.
+// Not currently necessary (as lowest supported version is in the 1.21 range)
+// but may become relevant in the future.
+java.disableAutoTargetJvm()
+
+// Task to delete ./dist where final files are output.
+tasks.register("cleanDist") {
+  delete("dist")
+}
+
+tasks.clean {
+  // Also delete distribution folder when cleaning.
+  dependsOn(tasks.named("cleanDist"))
+}

buildSrc/build.gradle.kts

@@ -0,0 +1,7 @@
+plugins {
+  `kotlin-dsl`
+}
+
+repositories {
+  gradlePluginPortal()
+}

buildSrc/src/main/kotlin/openinv-base.gradle.kts

@@ -0,0 +1,34 @@
+import org.gradle.jvm.toolchain.JavaLanguageVersion
+import org.gradle.kotlin.dsl.maven
+import org.gradle.kotlin.dsl.repositories
+import org.gradle.kotlin.dsl.dependencies
+
+plugins {
+  `java-library`
+}
+
+java {
+  toolchain.languageVersion = JavaLanguageVersion.of(21)
+}
+
+repositories {
+  mavenCentral()
+  maven("https://repo.papermc.io/repository/maven-public/")
+  maven("https://hub.spigotmc.org/nexus/content/groups/public/")
+}
+
+dependencies {
+  val libs = versionCatalogs.named("libs")
+  compileOnly(libs.findLibrary("annotations").orElseThrow())
+  compileOnly(libs.findLibrary("spigotapi").orElseThrow())
+}
+
+tasks {
+  withType<JavaCompile>().configureEach {
+    options.release = 21
+    options.encoding = Charsets.UTF_8.name()
+  }
+  withType<Javadoc>().configureEach {
+    options.encoding = Charsets.UTF_8.name()
+  }
+}

buildSrc/src/main/kotlin/remap-spigot.gradle.kts

@@ -0,0 +1,55 @@
+import java.nio.file.Path
+import java.nio.file.Paths
+
+val spigotRemap = configurations.create("spigotRemap")
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  spigotRemap("net.md-5:SpecialSource:1.11.4:shaded")
+}
+
+abstract class RemapTask
+  @Inject constructor(private val project: Project): DefaultTask() {
+
+  @get:Input
+  abstract var spigotVersion: String
+
+  @TaskAction
+  fun remapInputs() {
+    inputs.files.forEach {
+      remap(spigotVersion, it.toPath(), it.toPath().resolveSibling(it.name.replace(".jar", "-obf.jar")))
+    }
+  }
+
+  private fun remap(spigotVersion: String, jarPath: Path, obfPath: Path) {
+    // https://www.spigotmc.org/threads/510208/#post-4184317
+    val specialsource = project.configurations.named("spigotRemap").get().incoming.artifacts.artifacts
+      .first { it.id.componentIdentifier.toString() == "net.md-5:SpecialSource:1.11.4" }.file.path
+    val repo = Paths.get(project.repositories.mavenLocal().url)
+    val spigotDir = repo.resolve("org/spigotmc/spigot/$spigotVersion/")
+    val mappingDir = repo.resolve("org/spigotmc/minecraft-server/$spigotVersion/")
+
+    // Remap original Mojang-mapped jar to obfuscated intermediary
+    val mojangServer = spigotDir.resolve("spigot-$spigotVersion-remapped-mojang.jar")
+    val mojangMappings = mappingDir.resolve("minecraft-server-$spigotVersion-maps-mojang.txt")
+    remapPartial(specialsource, mojangServer, mojangMappings, jarPath, obfPath, true)
+
+    // Remap obfuscated intermediary jar to Spigot and replace original
+    val obfServer = spigotDir.resolve("spigot-$spigotVersion-remapped-obf.jar")
+    val spigotMappings = mappingDir.resolve("minecraft-server-$spigotVersion-maps-spigot.csrg")
+    remapPartial(specialsource, obfServer, spigotMappings, obfPath, jarPath, false)
+  }
+
+  private fun remapPartial(specialSource: String, serverJar: Path, mapping: Path, input: Path, output: Path, reverse: Boolean) {
+    project.providers.exec {
+      commandLine("java", "-cp", "$specialSource${File.pathSeparator}$serverJar",
+        "net.md_5.specialsource.SpecialSource", "--live",
+        "-i", "$input", "-o", "$output",
+        "-m", "$mapping",
+        if (reverse) "--reverse" else "")
+    }.result.get()
+  }
+}

common/build.gradle.kts

@@ -0,0 +1,7 @@
+plugins {
+  `openinv-base`
+}
+
+dependencies {
+  implementation(project(":openinvapi"))
+}

common/src/main/java/com/lishid/openinv/event/OpenEvents.java

@@ -0,0 +1,39 @@
+package com.lishid.openinv.event;
+
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.Event;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.UUID;
+
+/**
+ * Construct and call events.
+ */
+public final class OpenEvents {
+
+  public static boolean saveCancelled(@NotNull Player player) {
+    return call(new PlayerSaveEvent(player));
+  }
+
+  public static boolean saveCancelled(@NotNull ISpecialInventory inventory) {
+    return call(new OpenPlayerSaveEvent((Player) inventory.getPlayer(), inventory));
+  }
+
+  public static void notifyPlayerToggle(@NotNull PlayerToggle toggle, @NotNull UUID uuid, boolean state) {
+    Bukkit.getPluginManager().callEvent(new PlayerToggledEvent(toggle, uuid, state));
+  }
+
+  private static <T extends Event & Cancellable> boolean call(T event) {
+    Bukkit.getPluginManager().callEvent(event);
+    return event.isCancelled();
+  }
+
+  private OpenEvents() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+}

common/src/main/java/com/lishid/openinv/internal/Accessor.java

@@ -0,0 +1,24 @@
+package com.lishid.openinv.internal;
+
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public interface Accessor {
+
+  @NotNull
+  PlayerManager getPlayerManager();
+
+  @NotNull IAnySilentContainer getAnySilentContainer();
+
+  @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player);
+
+  @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player);
+
+  <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz);
+
+  void reload(@NotNull ConfigurationSection config);
+
+}

common/src/main/java/com/lishid/openinv/internal/AnySilentContainerBase.java

@@ -0,0 +1,106 @@
+package com.lishid.openinv.internal;
+
+import org.bukkit.block.Barrel;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.block.BlockState;
+import org.bukkit.block.EnderChest;
+import org.bukkit.block.ShulkerBox;
+import org.bukkit.block.data.BlockData;
+import org.bukkit.block.data.type.Chest;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Method;
+
+public abstract class AnySilentContainerBase implements IAnySilentContainer {
+
+  private static final @Nullable Method BLOCK_GET_STATE_BOOLEAN;
+
+  static {
+    @Nullable Method getState;
+    try {
+      //noinspection JavaReflectionMemberAccess
+      getState = Block.class.getMethod("getState", boolean.class);
+    } catch (NoSuchMethodException e) {
+      getState = null;
+    }
+    BLOCK_GET_STATE_BOOLEAN = getState;
+  }
+
+  private static BlockState getBlockState(Block block) {
+    // Paper: Get state without snapshotting.
+    if (BLOCK_GET_STATE_BOOLEAN != null) {
+      try {
+        return (BlockState) BLOCK_GET_STATE_BOOLEAN.invoke(block, false);
+      } catch (ReflectiveOperationException ignored) {
+        // If we encounter an issue, fall through to regular snapshotting method.
+      }
+    }
+    return block.getState();
+  }
+
+  @Override
+  public boolean isAnyContainerNeeded(@NotNull Block block) {
+    BlockState blockState = getBlockState(block);
+
+    // Barrels do not require AnyContainer.
+    if (blockState instanceof Barrel) {
+      return false;
+    }
+
+    // Enderchests require a non-occluding block on top to open.
+    if (blockState instanceof EnderChest) {
+      return block.getRelative(0, 1, 0).getType().isOccluding();
+    }
+
+    // Shulker boxes require half a block clear in the direction they open.
+    if (blockState instanceof ShulkerBox) {
+      return isShulkerBlocked(block);
+    }
+
+    if (!(blockState instanceof org.bukkit.block.Chest)) {
+      return false;
+    }
+
+    if (isChestBlocked(block)) {
+      return true;
+    }
+
+    BlockData blockData = block.getBlockData();
+    if (!(blockData instanceof Chest chest) || chest.getType() == Chest.Type.SINGLE) {
+      return false;
+    }
+
+    BlockFace relativeFace = switch (chest.getFacing()) {
+      case NORTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.WEST : BlockFace.EAST;
+      case EAST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.NORTH : BlockFace.SOUTH;
+      case SOUTH -> chest.getType() == Chest.Type.RIGHT ? BlockFace.EAST : BlockFace.WEST;
+      case WEST -> chest.getType() == Chest.Type.RIGHT ? BlockFace.SOUTH : BlockFace.NORTH;
+      default -> BlockFace.SELF;
+    };
+    Block relative = block.getRelative(relativeFace);
+
+    if (relative.getType() != block.getType()) {
+      return false;
+    }
+
+    BlockData relativeData = relative.getBlockData();
+    if (!(relativeData instanceof Chest relativeChest)) {
+      return false;
+    }
+
+    if (relativeChest.getFacing() != chest.getFacing()
+        || relativeChest.getType() != (chest.getType() == Chest.Type.RIGHT ? Chest.Type.LEFT : Chest.Type.RIGHT)) {
+      return false;
+    }
+
+    return isChestBlocked(relative);
+  }
+
+  @Override
+  public boolean isAnySilentContainer(@NotNull Block block) {
+    return isAnySilentContainer(getBlockState(block));
+  }
+
+}

common/src/main/java/com/lishid/openinv/internal/InternalOwned.java

@@ -0,0 +1,7 @@
+package com.lishid.openinv.internal;
+
+public interface InternalOwned<T> {
+
+  T getOwnerHandle();
+
+}

common/src/main/java/com/lishid/openinv/internal/InventoryViewTitle.java

@@ -0,0 +1,48 @@
+package com.lishid.openinv.internal;
+
+import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Objects;
+
+public enum InventoryViewTitle {
+
+  PLAYER_INVENTORY("container.player", "'s Inventory"),
+  ENDER_CHEST("container.enderchest", "'s Ender Chest");
+
+  private final String localizationKey;
+  private final String defaultSuffix;
+
+  InventoryViewTitle(String localizationKey, String defaultSuffix) {
+    this.localizationKey = localizationKey;
+    this.defaultSuffix = defaultSuffix;
+  }
+
+  public @NotNull String getTitle(
+      @NotNull LanguageManager lang,
+      @NotNull Player viewer,
+      @NotNull ISpecialInventory inventory) {
+    HumanEntity owner = inventory.getPlayer();
+
+    String localTitle = lang.getLocalizedMessage(
+            viewer,
+            localizationKey,
+            new Replacement("%player%", owner.getName()));
+    return Objects.requireNonNullElseGet(localTitle, () -> owner.getName() + defaultSuffix);
+  }
+
+  public static @Nullable InventoryViewTitle of(@NotNull ISpecialInventory inventory) {
+    if (inventory instanceof ISpecialPlayerInventory) {
+      return PLAYER_INVENTORY;
+    } else if (inventory instanceof ISpecialEnderChest) {
+      return ENDER_CHEST;
+    } else {
+      return null;
+    }
+  }
+
+}

common/src/main/java/com/lishid/openinv/internal/PlayerManager.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.internal;
+
+import org.bukkit.OfflinePlayer;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public interface PlayerManager {
+
+    /**
+     * Loads a Player for an OfflinePlayer.
+     * </p>
+     * This method is potentially blocking, and should not be called on the main thread.
+     *
+     * @param offline the OfflinePlayer
+     * @return the Player loaded
+     */
+    @Nullable Player loadPlayer(@NotNull OfflinePlayer offline);
+
+    /**
+     * Creates a new Player from an existing one that will function slightly better offline.
+     *
+     * @return the Player
+     */
+    @NotNull Player inject(@NotNull Player player);
+
+    /**
+     * Opens an ISpecialInventory for a Player.
+     *
+     * @param player the Player opening the ISpecialInventory
+     * @param inventory the Inventory
+     *`
+     * @return the InventoryView opened
+     */
+    @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory, boolean viewOnly);
+
+}

common/src/main/java/com/lishid/openinv/internal/ViewOnly.java

@@ -0,0 +1,4 @@
+package com.lishid.openinv.internal;
+
+public interface ViewOnly {
+}

common/src/main/java/com/lishid/openinv/util/Permissions.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util;
+
+import org.bukkit.permissions.Permissible;
+import org.jetbrains.annotations.NotNull;
+
+public enum Permissions {
+
+    INVENTORY_OPEN_SELF("inventory.open.self"),
+    INVENTORY_OPEN_OTHER("inventory.open.other"),
+    INVENTORY_EDIT_SELF("inventory.edit.self"),
+    INVENTORY_EDIT_OTHER("inventory.edit.other"),
+    INVENTORY_SLOT_HEAD_ANY("inventory.slot.head.any"),
+    INVENTORY_SLOT_CHEST_ANY("inventory.slot.chest.any"),
+    INVENTORY_SLOT_LEGS_ANY("inventory.slot.legs.any"),
+    INVENTORY_SLOT_FEET_ANY("inventory.slot.feet.any"),
+    INVENTORY_SLOT_DROP("inventory.slot.drop"),
+
+    ENDERCHEST_OPEN_SELF("enderchest.open.self"),
+    ENDERCHEST_OPEN_OTHER("enderchest.open.other"),
+    ENDERCHEST_EDIT_SELF("enderchest.edit.self"),
+    ENDERCHEST_EDIT_OTHER("enderchest.edit.other"),
+
+    ACCESS_CROSSWORLD("access.crossworld"),
+    ACCESS_OFFLINE("access.offline"),
+    ACCESS_ONLINE("access.online"),
+
+    SPECTATE_CLICK("spectate.click"),
+
+    CONTAINER_ANY("container.any"),
+    CONTAINER_SILENT("container.silent"),
+    SEARCH_INVENTORY("search.inventory"),
+    SEARCH_CONTAINER("search.container");
+
+    private final String permission;
+
+    Permissions(String permission) {
+        this.permission = "openinv." + permission;
+    }
+
+    public boolean hasPermission(@NotNull Permissible permissible) {
+        return permissible.hasPermission(permission);
+    }
+
+}

common/src/main/java/com/lishid/openinv/util/ReflectionHelper.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2011-2021 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Field;
+
+/**
+ * A utility for making reflection easier.
+ */
+public final class ReflectionHelper {
+
+    /**
+     * Grab an {@link Object} stored in a {@link Field} of another {@code Object}.
+     *
+     * <p>This casts the field to the correct class. Any issues will result in a {@code null} return value.
+     *
+     * @param fieldType the {@link Class} of {@code Object} stored in the {@code Field}
+     * @param holder the containing {@code Object}
+     * @param <T> the type of stored {@code Object}
+     * @return the first matching {@code Object} or {@code null} if none match
+     */
+    public static <T> @Nullable T grabObjectByType(final Object holder, final Class<T> fieldType) {
+        Field field = grabFieldByType(holder.getClass(), fieldType);
+
+        if (field != null) {
+            try {
+                return fieldType.cast(field.get(holder));
+            } catch (IllegalAccessException ignored) {
+                // Ignore issues obtaining field
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Grab a {@link Field} of an {@link Object}
+     *
+     * @param fieldType the {@link Class} of the object
+     * @param holderType the containing {@code Class}
+     * @return the first matching object or {@code null} if none match
+     */
+    public static @Nullable Field grabFieldByType(Class<?> holderType, Class<?> fieldType) {
+        for (Field field : holderType.getDeclaredFields()) {
+            if (fieldType.isAssignableFrom(field.getType())) {
+                field.setAccessible(true);
+                return field;
+            }
+        }
+
+        if (holderType.getSuperclass() != null) {
+            return grabFieldByType(fieldType, holderType.getSuperclass());
+        }
+
+        return null;
+    }
+
+    private ReflectionHelper() {
+        throw new IllegalStateException("Cannot create instance of utility class.");
+    }
+
+}

common/src/main/java/com/lishid/openinv/util/lang/LanguageManager.java

@@ -0,0 +1,319 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util.lang;
+
+import net.md_5.bungee.api.ChatMessageType;
+import net.md_5.bungee.api.chat.TextComponent;
+import org.bukkit.ChatColor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.configuration.Configuration;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.function.Predicate;
+import java.util.logging.Level;
+
+/**
+ * A simple language manager supporting both custom and bundled languages.
+ *
+ * @author Jikoo
+ */
+public class LanguageManager {
+
+    private final Plugin plugin;
+    private final File folder;
+    private final String defaultLocale;
+    private final Map<String, YamlConfiguration> locales;
+
+    public LanguageManager(@NotNull Plugin plugin, @NotNull String defaultLocale) {
+        this.plugin = plugin;
+        this.defaultLocale = defaultLocale;
+        this.locales = new HashMap<>();
+        this.folder = new File(plugin.getDataFolder(), "locale");
+
+        if (!folder.exists() && !folder.mkdirs()) {
+            plugin.getLogger().warning(() -> "Unable to create " + folder.getPath() + "! Languages may not be editable.");
+        }
+
+        reload();
+    }
+
+    public void reload() {
+        this.locales.clear();
+        getOrLoadLocale(defaultLocale);
+    }
+
+    private @NotNull YamlConfiguration getOrLoadLocale(@NotNull String locale) {
+        YamlConfiguration loaded = locales.get(locale);
+        if (loaded != null) {
+            return loaded;
+        }
+
+        LangLocation lang = bestMatch(locale, null);
+
+        // If a parent was a better match, check if it is already loaded.
+        if (!locale.equals(lang.locale)) {
+            loaded = locales.get(lang.locale);
+            if (loaded != null) {
+                locales.put(locale, loaded);
+                return loaded;
+            }
+        }
+
+        // Load locale config from disk and bundled locale defaults.
+        YamlConfiguration localeConfig = loadLocale(lang);
+
+        // If the locale is not the default locale, also handle any missing translations from the default locale.
+        if (!locale.equals(defaultLocale)) {
+            addTranslationFallthrough(lang, localeConfig);
+
+            if (plugin.getConfig().getBoolean("settings.secret.warn-about-guess-section", true)
+                    && localeConfig.isConfigurationSection("guess")) {
+                // Warn that guess section exists. This should run once per language per server restart
+                // when accessed by a user to hint to server owners that they can make UX improvements.
+                plugin.getLogger().info(() -> "[LanguageManager] Missing translations from " + lang.locale + ".yml! Check the guess section!");
+            }
+        }
+
+        locales.put(locale, localeConfig);
+        locales.put(lang.locale, localeConfig);
+
+        return localeConfig;
+    }
+
+    private @NotNull LangLocation bestMatch(@NotNull String locale, @Nullable LangLocation initial) {
+        File file = new File(folder, locale + ".yml");
+        InputStream bundled = plugin.getResource("locale/" + locale + ".yml");
+
+        if (file.exists() || bundled != null) {
+            return new LangLocation(locale, file, bundled);
+        }
+
+        if (initial == null) {
+            initial = new LangLocation(locale, file, null);
+        }
+
+        int lastSeparator = locale.lastIndexOf('_');
+
+        // Must be at least some content before separator.
+        if (lastSeparator < 1) {
+            return initial;
+        }
+
+        return bestMatch(locale.substring(0, lastSeparator), initial);
+    }
+
+    private @NotNull YamlConfiguration loadLocale(@NotNull LangLocation lang) {
+        YamlConfiguration localeConfigDefaults;
+        if (lang.bundled == null) {
+            localeConfigDefaults = new YamlConfiguration();
+        } else {
+            try (BufferedReader reader = new BufferedReader(new InputStreamReader(lang.bundled, StandardCharsets.UTF_8))) {
+                localeConfigDefaults = YamlConfiguration.loadConfiguration(reader);
+            } catch (IOException e) {
+                plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to load resource " + lang.locale + ".yml");
+                localeConfigDefaults = new YamlConfiguration();
+            }
+        }
+
+        if (!lang.file.exists()) {
+            // If the file does not exist on disk, save bundled defaults.
+            try {
+                localeConfigDefaults.save(lang.file);
+            } catch (IOException e) {
+                plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to save resource " + lang.locale + ".yml");
+            }
+            // Return loaded bundled locale.
+            return localeConfigDefaults;
+        }
+
+        // If the file does exist on disk, load it.
+        YamlConfiguration localeConfig = YamlConfiguration.loadConfiguration(lang.file);
+        // Check for missing translations from the bundled file.
+        List<String> newKeys = getMissingKeys(localeConfigDefaults, localeConfig::isSet);
+
+        if (newKeys.isEmpty()) {
+            return localeConfig;
+        }
+
+        // Get guess section for missing keys.
+        ConfigurationSection guess = localeConfig.getConfigurationSection("guess");
+
+        for (String newKey : newKeys) {
+            // Set all missing keys to defaults.
+            localeConfig.set(newKey, localeConfigDefaults.get(newKey));
+
+            // Delete relevant guess keys in case this is a new translation.
+            if (guess != null) {
+                guess.set(newKey, null);
+            }
+        }
+
+        // If guess section is empty, delete it.
+        if (guess != null && guess.getKeys(false).isEmpty()) {
+            localeConfig.set("guess", null);
+        }
+
+        plugin.getLogger().info(() -> "[LanguageManager] Added new translation keys to " + lang.locale + ".yml: " + String.join(", ", newKeys));
+
+        // Write new keys to disk.
+        try {
+            localeConfig.save(lang.file);
+        } catch (IOException e) {
+            plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to save resource " + lang.locale + ".yml");
+        }
+
+        return localeConfig;
+    }
+
+    private void addTranslationFallthrough(@NotNull LangLocation location, @NotNull YamlConfiguration localeConfig) {
+        YamlConfiguration defaultLocaleConfig = locales.get(defaultLocale);
+
+        // Get missing keys. Keys that already have a guess value are not new and don't need to trigger another write.
+        List<String> missingKeys = getMissingKeys(
+                defaultLocaleConfig,
+                key -> localeConfig.isSet(key) || localeConfig.isSet("guess." + key));
+
+        if (!missingKeys.isEmpty()) {
+            // Set up guess section for missing keys.
+            for (String key : missingKeys) {
+                localeConfig.set("guess." + key, defaultLocaleConfig.get(key));
+            }
+
+            // Write modified guess section to disk.
+            try {
+                localeConfig.save(location.file);
+            } catch (IOException e) {
+                plugin.getLogger().log(Level.WARNING, e, () -> "[LanguageManager] Unable to save resource " + location.locale + ".yml");
+            }
+        }
+
+        // Fall through to default locale.
+        localeConfig.setDefaults(defaultLocaleConfig);
+    }
+
+    private @NotNull List<String> getMissingKeys(
+            @NotNull Configuration configurationDefault,
+            @NotNull Predicate<String> nodeSetPredicate) {
+        List<String> missingKeys = new ArrayList<>();
+        for (String key : configurationDefault.getKeys(true)) {
+            if (!configurationDefault.isConfigurationSection(key) && !nodeSetPredicate.test(key)) {
+                // Missing keys are non-section keys that fail the predicate.
+                missingKeys.add(key);
+            }
+        }
+        return missingKeys;
+    }
+
+    public @Nullable String getValue(@NotNull String key, @Nullable String locale) {
+        String value = getOrLoadLocale(locale == null ? defaultLocale : locale.toLowerCase(Locale.ENGLISH)).getString(key);
+        if (value == null || value.isBlank()) {
+            return null;
+        }
+
+        value = ChatColor.translateAlternateColorCodes('&', value);
+
+        return value;
+    }
+
+    public @Nullable String getValue(@NotNull String key, @Nullable String locale, Replacement @NotNull ... replacements) {
+        String value = getValue(key, locale);
+
+        if (value == null) {
+            return null;
+        }
+
+        for (Replacement replacement : replacements) {
+            value = value.replace(replacement.placeholder(), replacement.value());
+        }
+
+        return value;
+    }
+
+    public @Nullable String getLocalizedMessage(@NotNull CommandSender sender, @NotNull String key) {
+        return getValue(key, getLocale(sender));
+    }
+
+    public @Nullable String getLocalizedMessage(
+        @NotNull CommandSender sender,
+        @NotNull String key,
+        Replacement @NotNull ... replacements) {
+        return getValue(key, getLocale(sender), replacements);
+    }
+
+    private @NotNull String getLocale(@NotNull CommandSender sender) {
+        if (sender instanceof Player) {
+            return ((Player) sender).getLocale();
+        } else {
+            return plugin.getConfig().getString("settings.locale", "en");
+        }
+    }
+
+    public void sendMessage(@NotNull CommandSender sender, @NotNull String key) {
+        String message = getLocalizedMessage(sender, key);
+
+        if (message != null && !message.isEmpty()) {
+            sender.sendMessage(message);
+        }
+    }
+
+    public void sendMessage(@NotNull CommandSender sender, @NotNull String key, Replacement @NotNull... replacements) {
+        String message = getLocalizedMessage(sender, key, replacements);
+
+        if (message != null && !message.isEmpty()) {
+            sender.sendMessage(message);
+        }
+    }
+
+    public void sendSystemMessage(@NotNull Player player, @NotNull String key) {
+        String message = getLocalizedMessage(player, key);
+
+        if (message == null) {
+            return;
+        }
+
+        int newline = message.indexOf('\n');
+        if (newline != -1) {
+            // No newlines in action bar chat.
+            message = message.substring(0, newline);
+        }
+
+        if (message.isEmpty()) {
+            return;
+        }
+
+        player.spigot().sendMessage(ChatMessageType.ACTION_BAR, TextComponent.fromLegacy(message));
+    }
+
+    private record LangLocation(@NotNull String locale, @NotNull File file, @Nullable InputStream bundled) {}
+
+}

common/src/main/java/com/lishid/openinv/util/lang/Replacement.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util.lang;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A data holder for string replacement in translations.
+ *
+ * @param placeholder the placeholder to be replaced
+ * @param value the value to insert
+ */
+public record Replacement(@NotNull String placeholder, @NotNull String value) {
+
+}

gradle.properties

@@ -0,0 +1,9 @@
+# Project meta
+group = com.lishid.openinv
+version = 5.1.7
+description = A Bukkit plugin for opening normally-inaccessible inventories.
+
+# Gradle configuration
+org.gradle.parallel=true
+org.gradle.caching=true
+org.gradle.configuration-cache=true

gradle/libs.versions.toml

@@ -0,0 +1,19 @@
+[versions]
+spigotapi = "1.21.4-R0.1-SNAPSHOT"
+spigot = "1.21.4-R0.1-SNAPSHOT"
+specialsource = "1.11.4"
+planarwrappers = "3.3.0"
+annotations = "26.0.2"
+paperweight = "2.0.0-beta.14"
+shadow = "8.3.5"
+
+[libraries]
+spigotapi = { module = "org.spigotmc:spigot-api", version.ref = "spigotapi" }
+spigot = { module = "org.spigotmc:spigot", version.ref = "spigot" }
+specialsource = { module = "net.md-5:SpecialSource", version.ref = "specialsource" }
+planarwrappers = { module = "com.github.jikoo:planarwrappers", version.ref = "planarwrappers" }
+annotations = { module = "org.jetbrains:annotations", version.ref = "annotations" }
+
+[plugins]
+paperweight = { id = "io.papermc.paperweight.userdev", version.ref = "paperweight" }
+shadow = { id = "com.gradleup.shadow", version.ref = "shadow" }

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

internal/common/build.gradle.kts

@@ -0,0 +1,51 @@
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+
+plugins {
+  `openinv-base`
+  alias(libs.plugins.paperweight)
+}
+
+configurations.all {
+  resolutionStrategy.capabilitiesResolution.withCapability("org.spigotmc:spigot-api") {
+    val paper = candidates.firstOrNull {
+      it.id.let {
+        id -> id is ModuleComponentIdentifier && id.module == "paper-api"
+      }
+    }
+    if (paper != null) {
+      select(paper)
+    }
+    because("module is written for Paper servers")
+  }
+}
+
+dependencies {
+  implementation(project(":openinvapi"))
+  implementation(project(":openinvcommon"))
+
+  paperweight.paperDevBundle("1.21.4-R0.1-SNAPSHOT")
+}
+
+val spigot = tasks.register<ShadowJar>("spigotRelocations") {
+  dependsOn(tasks.jar)
+  from(sourceSets.main.get().output)
+  relocate("com.lishid.openinv.internal.common", "com.lishid.openinv.internal.reobf")
+  // TODO pass from Spigot adapter somehow. Can tasks be added by another project? Can we fetch a global config?
+  relocate("org.bukkit.craftbukkit", "org.bukkit.craftbukkit.v1_21_R3")
+  archiveClassifier = "spigot"
+}
+
+configurations {
+  consumable("spigotRelocated") {
+    attributes {
+      attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.LIBRARY))
+      attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
+      attribute(Bundling.BUNDLING_ATTRIBUTE, objects.named(Bundling.EXTERNAL))
+      attribute(LibraryElements.LIBRARY_ELEMENTS_ATTRIBUTE, objects.named(LibraryElements.JAR))
+    }
+  }
+}
+
+artifacts {
+  add("spigotRelocated", spigot)
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/InternalAccessor.java

@@ -0,0 +1,81 @@
+package com.lishid.openinv.internal.common;
+
+import com.lishid.openinv.internal.Accessor;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.internal.common.container.AnySilentContainer;
+import com.lishid.openinv.internal.common.container.OpenEnderChest;
+import com.lishid.openinv.internal.common.container.OpenInventory;
+import com.lishid.openinv.internal.common.container.Placeholders;
+import com.lishid.openinv.internal.common.player.PlayerManager;
+import com.lishid.openinv.util.lang.LanguageManager;
+import net.minecraft.world.Container;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class InternalAccessor implements Accessor {
+
+  private final @NotNull Logger logger;
+  private final @NotNull PlayerManager manager;
+  private final @NotNull AnySilentContainer anySilentContainer;
+
+  public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
+    this.logger = logger;
+    manager = new PlayerManager(logger);
+    anySilentContainer = new AnySilentContainer(logger, lang);
+  }
+
+  @Override
+  public @NotNull PlayerManager getPlayerManager() {
+    return manager;
+  }
+
+  @Override
+  public @NotNull IAnySilentContainer getAnySilentContainer() {
+    return anySilentContainer;
+  }
+
+  @Override
+  public @NotNull ISpecialPlayerInventory createPlayerInventory(@NotNull Player player) {
+    return new OpenInventory(player);
+  }
+
+  @Override
+  public @NotNull ISpecialEnderChest createEnderChest(@NotNull Player player) {
+    return new OpenEnderChest(player);
+  }
+
+  @Override
+  public <T extends ISpecialInventory> @Nullable T get(@NotNull Inventory bukkitInventory, @NotNull Class<T> clazz) {
+    if (!(bukkitInventory instanceof CraftInventory craftInventory)) {
+      return null;
+    }
+    Container container = craftInventory.getInventory();
+    if (clazz.isInstance(container)) {
+      return clazz.cast(container);
+    }
+    return null;
+  }
+
+  @Override
+  public void reload(@NotNull ConfigurationSection config) {
+    ConfigurationSection placeholders = config.getConfigurationSection("placeholders");
+    if (placeholders != null) {
+      try {
+        Placeholders.load(placeholders);
+      } catch (Exception e) {
+        logger.log(Level.WARNING, "Caught exception loading placeholder overrides!", e);
+      }
+    }
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/AnySilentContainer.java

@@ -0,0 +1,210 @@
+/*
+ * Copyright (C) 2011-2023 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.internal.common.container;
+
+import com.lishid.openinv.internal.AnySilentContainerBase;
+import com.lishid.openinv.internal.common.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.common.player.PlayerManager;
+import com.lishid.openinv.util.ReflectionHelper;
+import com.lishid.openinv.util.lang.LanguageManager;
+import net.minecraft.core.BlockPos;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.server.level.ServerPlayerGameMode;
+import net.minecraft.world.MenuProvider;
+import net.minecraft.world.SimpleMenuProvider;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.PlayerEnderChestContainer;
+import net.minecraft.world.level.GameType;
+import net.minecraft.world.level.block.BarrelBlock;
+import net.minecraft.world.level.block.Block;
+import net.minecraft.world.level.block.ChestBlock;
+import net.minecraft.world.level.block.ShulkerBoxBlock;
+import net.minecraft.world.level.block.TrappedChestBlock;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.entity.EnderChestBlockEntity;
+import net.minecraft.world.level.block.entity.RandomizableContainerBlockEntity;
+import net.minecraft.world.level.block.state.BlockState;
+import org.bukkit.GameMode;
+import org.bukkit.Material;
+import org.bukkit.Statistic;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Field;
+import java.util.logging.Logger;
+
+public class AnySilentContainer extends AnySilentContainerBase {
+
+    private final @NotNull Logger logger;
+    private final @NotNull LanguageManager lang;
+    private @Nullable Field serverPlayerGameModeGameType;
+
+    public AnySilentContainer(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        this.logger = logger;
+        this.lang = lang;
+        try {
+            try {
+                this.serverPlayerGameModeGameType = ServerPlayerGameMode.class.getDeclaredField("gameModeForPlayer");
+                this.serverPlayerGameModeGameType.setAccessible(true);
+            } catch (NoSuchFieldException e) {
+                logger.warning("The field ServerPlayerGameMode#gameModeForPlayer is no longer present!");
+                logger.warning("Please report this at https://github.com/Jikoo/OpenInv/issues");
+                logger.warning("Attempting to fall through using reflection. Please verify that SilentContainer does not fail.");
+                // N.B. gameModeForPlayer is (for now) declared before previousGameModeForPlayer so silent shouldn't break.
+                this.serverPlayerGameModeGameType = ReflectionHelper.grabFieldByType(ServerPlayerGameMode.class, GameType.class);
+            }
+        } catch (SecurityException e) {
+            logger.warning("Unable to directly write player game mode! SilentContainer will fail.");
+            logger.log(java.util.logging.Level.WARNING, "Error obtaining GameType field", e);
+        }
+    }
+
+    @Override
+    public boolean activateContainer(
+            @NotNull final Player bukkitPlayer,
+            final boolean silentchest,
+            @NotNull final org.bukkit.block.Block bukkitBlock) {
+
+        // Silent ender chest is API-only
+        if (silentchest && bukkitBlock.getType() == Material.ENDER_CHEST) {
+            bukkitPlayer.openInventory(bukkitPlayer.getEnderChest());
+            bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
+            return true;
+        }
+
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
+
+        final net.minecraft.world.level.Level level = player.level();
+        final BlockPos blockPos = new BlockPos(bukkitBlock.getX(), bukkitBlock.getY(), bukkitBlock.getZ());
+        final BlockEntity blockEntity = level.getBlockEntity(blockPos);
+
+        if (blockEntity == null) {
+            return false;
+        }
+
+        if (blockEntity instanceof EnderChestBlockEntity enderChestTile) {
+            // Anychest ender chest. See net.minecraft.world.level.block.EnderChestBlock
+            PlayerEnderChestContainer enderChest = player.getEnderChestInventory();
+            enderChest.setActiveChest(enderChestTile);
+            player.openMenu(new SimpleMenuProvider((containerCounter, playerInventory, ignored) -> {
+                MenuType<?> containers = OpenChestMenu.getChestMenuType(enderChest.getContainerSize());
+                int rows = enderChest.getContainerSize() / 9;
+                return new ChestMenu(containers, containerCounter, playerInventory, enderChest, rows);
+            }, Component.translatable("container.enderchest")));
+            bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
+            return true;
+        }
+
+        if (!(blockEntity instanceof MenuProvider menuProvider)) {
+            return false;
+        }
+
+        BlockState blockState = level.getBlockState(blockPos);
+        Block block = blockState.getBlock();
+
+        if (block instanceof ChestBlock chestBlock) {
+
+            // boolean flag: do not check if chest is blocked
+            menuProvider = chestBlock.getMenuProvider(blockState, level, blockPos, true);
+
+            if (menuProvider == null) {
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                return false;
+            }
+
+            if (block instanceof TrappedChestBlock) {
+                bukkitPlayer.incrementStatistic(Statistic.TRAPPED_CHEST_TRIGGERED);
+            } else {
+                bukkitPlayer.incrementStatistic(Statistic.CHEST_OPENED);
+            }
+        }
+
+        if (block instanceof ShulkerBoxBlock) {
+            bukkitPlayer.incrementStatistic(Statistic.SHULKER_BOX_OPENED);
+        }
+
+        if (block instanceof BarrelBlock) {
+            bukkitPlayer.incrementStatistic(Statistic.OPEN_BARREL);
+        }
+
+        // AnyChest only - SilentChest not active, container unsupported, or unnecessary.
+        if (!silentchest || player.gameMode.getGameModeForPlayer() == GameType.SPECTATOR) {
+            player.openMenu(menuProvider);
+            return true;
+        }
+
+        // SilentChest requires access to setting players' game mode directly.
+        if (this.serverPlayerGameModeGameType == null) {
+            return false;
+        }
+
+        if (blockEntity instanceof RandomizableContainerBlockEntity lootable) {
+            if (lootable.lootTable != null) {
+                lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+                return false;
+            }
+        }
+
+        GameType gameType = player.gameMode.getGameModeForPlayer();
+        this.forceGameType(player, GameType.SPECTATOR);
+        player.openMenu(menuProvider);
+        this.forceGameType(player, gameType);
+        return true;
+    }
+
+    @Override
+    public void deactivateContainer(@NotNull final Player bukkitPlayer) {
+        if (this.serverPlayerGameModeGameType == null || bukkitPlayer.getGameMode() == GameMode.SPECTATOR) {
+            return;
+        }
+
+        ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
+
+        // Force game mode change without informing plugins or players.
+        // Regular game mode set calls GameModeChangeEvent and is cancellable.
+        GameType gameType = player.gameMode.getGameModeForPlayer();
+        this.forceGameType(player, GameType.SPECTATOR);
+
+        // ServerPlayer#closeContainer cannot be called without entering an
+        // infinite loop because this method is called during inventory close.
+        // From ServerPlayer#closeContainer -> CraftEventFactory#handleInventoryCloseEvent
+        player.containerMenu.transferTo(player.inventoryMenu, player.getBukkitEntity());
+        // From ServerPlayer#closeContainer
+        player.doCloseContainer();
+        // Regular inventory close will handle the rest - packet sending, etc.
+
+        // Revert forced game mode.
+        this.forceGameType(player, gameType);
+    }
+
+    private void forceGameType(final ServerPlayer player, final GameType gameMode) {
+        if (this.serverPlayerGameModeGameType == null) {
+            // No need to warn repeatedly, error on startup and lack of function should be enough.
+            return;
+        }
+        try {
+            this.serverPlayerGameModeGameType.setAccessible(true);
+            this.serverPlayerGameModeGameType.set(player.gameMode, gameMode);
+        } catch (IllegalArgumentException | IllegalAccessException e) {
+            logger.log(java.util.logging.Level.WARNING, "Error bypassing GameModeChangeEvent", e);
+        }
+    }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/OpenEnderChest.java

@@ -0,0 +1,196 @@
+package com.lishid.openinv.internal.common.container;
+
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.InternalOwned;
+import com.lishid.openinv.internal.common.container.menu.OpenEnderChestMenu;
+import com.lishid.openinv.internal.common.player.PlayerManager;
+import net.minecraft.core.NonNullList;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.entity.player.StackedItemContents;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.StackedContentsCompatible;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class OpenEnderChest implements Container, StackedContentsCompatible, InternalOwned<ServerPlayer>,
+    ISpecialEnderChest {
+
+  private CraftInventory inventory;
+  private @NotNull ServerPlayer owner;
+  private NonNullList<ItemStack> items;
+  private int maxStack = 64;
+  private final List<HumanEntity> transaction = new ArrayList<>();
+
+  public OpenEnderChest(@NotNull org.bukkit.entity.Player player) {
+    this.owner = PlayerManager.getHandle(player);
+    this.items = owner.getEnderChestInventory().items;
+  }
+
+  @Override
+  public @NotNull ServerPlayer getOwnerHandle() {
+    return owner;
+  }
+
+  @Override
+  public @NotNull org.bukkit.inventory.Inventory getBukkitInventory() {
+    if (inventory == null) {
+      inventory = new CraftInventory(this) {
+        @Override
+        public @NotNull InventoryType getType() {
+          return InventoryType.ENDER_CHEST;
+        }
+      };
+    }
+    return inventory;
+  }
+
+  @Override
+  public void setPlayerOnline(@NotNull org.bukkit.entity.Player player) {
+    owner = PlayerManager.getHandle(player);
+    NonNullList<ItemStack> activeItems = owner.getEnderChestInventory().items;
+
+    // Guard against size changing. Theoretically on Purpur all row variations still have 6 rows internally.
+    int max = Math.min(items.size(), activeItems.size());
+    for (int index = 0; index < max; ++index) {
+      activeItems.set(index, items.get(index));
+    }
+
+    items = activeItems;
+  }
+
+  @Override
+  public void setPlayerOffline() {}
+
+  @Override
+  public @NotNull org.bukkit.entity.Player getPlayer() {
+    return owner.getBukkitEntity();
+  }
+
+  @Override
+  public int getContainerSize() {
+    return items.size();
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return items.stream().allMatch(ItemStack::isEmpty);
+  }
+
+  @Override
+  public @NotNull ItemStack getItem(int index) {
+    return index >= 0 && index < items.size() ? items.get(index) : ItemStack.EMPTY;
+  }
+
+  @Override
+  public @NotNull ItemStack removeItem(int index, int amount) {
+    ItemStack itemstack = ContainerHelper.removeItem(items, index, amount);
+
+    if (!itemstack.isEmpty()) {
+      setChanged();
+    }
+
+    return itemstack;
+  }
+
+  @Override
+  public @NotNull ItemStack removeItemNoUpdate(int index) {
+    return index >= 0 && index < items.size() ? items.set(index, ItemStack.EMPTY) : ItemStack.EMPTY;
+  }
+
+  @Override
+  public void setItem(int index, @NotNull ItemStack itemStack) {
+    if (index >= 0 && index < items.size()) {
+      items.set(index, itemStack);
+    }
+  }
+
+  @Override
+  public int getMaxStackSize() {
+    return maxStack;
+  }
+
+  @Override
+  public void setChanged() {
+    this.owner.getEnderChestInventory().setChanged();
+  }
+
+  @Override
+  public boolean stillValid(@NotNull Player player) {
+    return true;
+  }
+
+  @Override
+  public @NotNull List<ItemStack> getContents() {
+    return items;
+  }
+
+  @Override
+  public void onOpen(@NotNull CraftHumanEntity craftHumanEntity) {
+    transaction.add(craftHumanEntity);
+  }
+
+  @Override
+  public void onClose(@NotNull CraftHumanEntity craftHumanEntity) {
+    transaction.remove(craftHumanEntity);
+  }
+
+  @Override
+  public @NotNull List<HumanEntity> getViewers() {
+    return transaction;
+  }
+
+  @Override
+  public org.bukkit.entity.Player getOwner() {
+    return getPlayer();
+  }
+
+  @Override
+  public void setMaxStackSize(int size) {
+    maxStack = size;
+  }
+
+  @Override
+  public @Nullable Location getLocation() {
+    return null;
+  }
+
+  @Override
+  public void clearContent() {
+    items.clear();
+    setChanged();
+  }
+
+  @Override
+  public void fillStackedContents(@NotNull StackedItemContents stackedContents) {
+    for (ItemStack itemstack : items) {
+      stackedContents.accountStack(itemstack);
+    }
+  }
+
+  public Component getTitle() {
+    return Component.translatableWithFallback("openinv.container.enderchest.prefix", "", owner.getName())
+        .append(Component.translatable("container.enderchest"))
+        .append(Component.translatableWithFallback("openinv.container.enderchest.suffix", " - %s", owner.getName()));
+  }
+
+  public @Nullable AbstractContainerMenu createMenu(Player player, int i, boolean viewOnly) {
+    if (player instanceof ServerPlayer serverPlayer) {
+      return new OpenEnderChestMenu(this, serverPlayer, i, viewOnly);
+    }
+    return null;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/OpenInventory.java

@@ -0,0 +1,364 @@
+package com.lishid.openinv.internal.common.container;
+
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.internal.InternalOwned;
+import com.lishid.openinv.internal.common.container.bukkit.OpenPlayerInventory;
+import com.lishid.openinv.internal.common.container.menu.OpenInventoryMenu;
+import com.lishid.openinv.internal.common.container.slot.Content;
+import com.lishid.openinv.internal.common.container.slot.ContentCrafting;
+import com.lishid.openinv.internal.common.container.slot.ContentCraftingResult;
+import com.lishid.openinv.internal.common.container.slot.ContentCursor;
+import com.lishid.openinv.internal.common.container.slot.ContentDrop;
+import com.lishid.openinv.internal.common.container.slot.ContentEquipment;
+import com.lishid.openinv.internal.common.container.slot.ContentList;
+import com.lishid.openinv.internal.common.container.slot.ContentOffHand;
+import com.lishid.openinv.internal.common.container.slot.ContentViewOnly;
+import com.lishid.openinv.internal.common.container.slot.SlotViewOnly;
+import com.lishid.openinv.internal.common.player.PlayerManager;
+import net.minecraft.ChatFormatting;
+import net.minecraft.core.NonNullList;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.chat.MutableComponent;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class OpenInventory implements Container, InternalOwned<ServerPlayer>, ISpecialPlayerInventory {
+
+  private final List<Content> slots;
+  private final int size;
+  private ServerPlayer owner;
+  private int maxStackSize = 99;
+  private CraftInventory bukkitEntity;
+  public List<HumanEntity> transaction = new ArrayList<>();
+
+  public OpenInventory(@NotNull org.bukkit.entity.Player bukkitPlayer) {
+    owner = PlayerManager.getHandle(bukkitPlayer);
+
+    // Get total size, rounding up to nearest 9 for client compatibility.
+    int rawSize = owner.getInventory().getContainerSize() + owner.inventoryMenu.getCraftSlots().getContainerSize() + 1;
+    size = ((int) Math.ceil(rawSize / 9.0)) * 9;
+
+    slots = NonNullList.withSize(size, new ContentViewOnly(owner));
+    setupSlots();
+  }
+
+  private void setupSlots() {
+    // Top of inventory: Regular contents.
+    int nextIndex = addMainInventory();
+
+    // If inventory is expected size, we can arrange slots to be pretty.
+    Inventory ownerInv = owner.getInventory();
+    if (ownerInv.items.size() == 36
+        && ownerInv.armor.size() == 4
+        && ownerInv.offhand.size() == 1
+        && owner.inventoryMenu.getCraftSlots().getContainerSize() == 4) {
+      // Armor slots: Bottom left.
+      addArmor(36);
+      // Off-hand: Below chestplate.
+      addOffHand(46);
+      // Drop slot: Bottom right.
+      slots.set(53, new ContentDrop(owner));
+      // Cursor slot: Above drop.
+      slots.set(44, new ContentCursor(owner));
+
+      // Crafting is displayed in the bottom right corner.
+      // As we're using the pretty view, this is a 3x2.
+      addCrafting(41, true);
+      return;
+    }
+
+    // Otherwise we'll just add elements linearly.
+    nextIndex = addArmor(nextIndex);
+    nextIndex = addOffHand(nextIndex);
+    nextIndex = addCrafting(nextIndex, false);
+    slots.set(nextIndex, new ContentCursor(owner));
+    // Drop slot last.
+    slots.set(slots.size() - 1, new ContentDrop(owner));
+  }
+
+  private int addMainInventory() {
+    int listSize = owner.getInventory().items.size();
+    // Hotbar slots are 0-8. We want those to appear on the bottom of the inventory like a normal player inventory,
+    // so everything else needs to move up a row.
+    int hotbarDiff = listSize - 9;
+    for (int localIndex = 0; localIndex < listSize; ++localIndex) {
+      InventoryType.SlotType type;
+      int invIndex;
+      if (localIndex < hotbarDiff) {
+        invIndex = localIndex + 9;
+        type = InventoryType.SlotType.CONTAINER;
+      } else {
+        type = InventoryType.SlotType.QUICKBAR;
+        invIndex = localIndex - hotbarDiff;
+      }
+
+      slots.set(localIndex, new ContentList(owner, invIndex, type) {
+        @Override
+        public void setHolder(@NotNull ServerPlayer holder) {
+          items = holder.getInventory().items;
+        }
+      });
+    }
+    return listSize;
+  }
+
+  private int addArmor(int startIndex) {
+    int listSize = owner.getInventory().armor.size();
+
+    for (int i = 0; i < listSize; ++i) {
+      // Armor slots go bottom to top; boots are slot 0, helmet is slot 3.
+      // Since we have to display horizontally due to space restrictions,
+      // making the left side the "top" is more user-friendly.
+      int armorIndex;
+      EquipmentSlot slot;
+      switch (i) {
+        case 3 -> {
+          armorIndex = 0;
+          slot = EquipmentSlot.FEET;
+        }
+        case 2 -> {
+          armorIndex = 1;
+          slot = EquipmentSlot.LEGS;
+        }
+        case 1 -> {
+          armorIndex = 2;
+          slot = EquipmentSlot.CHEST;
+        }
+        case 0 -> {
+          armorIndex = 3;
+          slot = EquipmentSlot.HEAD;
+        }
+        default -> {
+          // In the event that new armor slots are added, they can be placed at the end.
+          armorIndex = i;
+          slot = EquipmentSlot.MAINHAND;
+        }
+      }
+
+      slots.set(startIndex + i, new ContentEquipment(owner, armorIndex, slot));
+    }
+
+    return startIndex + listSize;
+  }
+
+  private int addOffHand(int startIndex) {
+    int listSize = owner.getInventory().offhand.size();
+    for (int localIndex = 0; localIndex < listSize; ++localIndex) {
+      slots.set(startIndex + localIndex, new ContentOffHand(owner, localIndex));
+    }
+    return startIndex + listSize;
+  }
+
+  private int addCrafting(int startIndex, boolean pretty) {
+    int listSize = owner.inventoryMenu.getCraftSlots().getContents().size();
+    pretty &= listSize == 4;
+
+    for (int localIndex = 0; localIndex < listSize; ++localIndex) {
+      // Pretty display is a 2x2 rather than linear.
+      // If index is in top row, grid is not 2x2, or pretty is disabled, just use current index.
+      // Otherwise, subtract 2 and add 9 to start in the same position on the next row.
+      int modIndex = startIndex + (localIndex < 2 || !pretty ? localIndex : localIndex + 7);
+
+      slots.set(modIndex, new ContentCrafting(owner, localIndex));
+    }
+
+    if (pretty) {
+      slots.set(startIndex + 2, new ContentViewOnly(owner) {
+        @Override
+        public Slot asSlot(Container container, int slot, int x, int y) {
+          return new SlotViewOnly(container, slot, x, y) {
+            @Override
+            public ItemStack getOrDefault() {
+              return Placeholders.craftingOutput;
+            }
+          };
+        }
+      });
+      slots.set(startIndex + 11, new ContentCraftingResult(owner));
+    }
+
+    return startIndex + listSize;
+  }
+
+  public Slot getMenuSlot(int index, int x, int y) {
+    return slots.get(index).asSlot(this, index, x, y);
+  }
+
+  public InventoryType.SlotType getSlotType(int index) {
+    return slots.get(index).getSlotType();
+  }
+
+  public @NotNull Component getTitle(@Nullable ServerPlayer viewer) {
+    MutableComponent component = Component.empty();
+    // Prefix for use with custom bitmap image fonts.
+    if (owner.equals(viewer)) {
+      component.append(
+          Component.translatableWithFallback("openinv.container.inventory.self", "")
+              .withStyle(style -> style
+                  .withFont(ResourceLocation.parse("openinv:font/inventory"))
+                  .withColor(ChatFormatting.WHITE)));
+    } else {
+      component.append(
+          Component.translatableWithFallback("openinv.container.inventory.other", "")
+              .withStyle(style -> style
+                  .withFont(ResourceLocation.parse("openinv:font/inventory"))
+                  .withColor(ChatFormatting.WHITE)));
+    }
+    // Normal title: "Inventory - OwnerName"
+    component.append(Component.translatableWithFallback("openinv.container.inventory.prefix", "", owner.getName()))
+        .append(Component.translatable("container.inventory"))
+        .append(Component.translatableWithFallback("openinv.container.inventory.suffix", " - %s", owner.getName()));
+    return component;
+  }
+
+  @Override
+  public ServerPlayer getOwnerHandle() {
+    return owner;
+  }
+
+  @Override
+  public @NotNull org.bukkit.inventory.Inventory getBukkitInventory() {
+    if (bukkitEntity == null) {
+      bukkitEntity = new OpenPlayerInventory(this);
+    }
+    return bukkitEntity;
+  }
+
+  @Override
+  public void setPlayerOnline(@NotNull org.bukkit.entity.Player player) {
+    ServerPlayer newOwner = PlayerManager.getHandle(player);
+    // Only transfer regular inventory - crafting and cursor slots are transient.
+    newOwner.getInventory().replaceWith(owner.getInventory());
+    owner = newOwner;
+    // Update slots to point to new inventory.
+    slots.forEach(slot -> slot.setHolder(newOwner));
+  }
+
+  @Override
+  public void setPlayerOffline() {}
+
+  @Override
+  public boolean isInUse() {
+    return !transaction.isEmpty();
+  }
+
+  @Override
+  public @NotNull org.bukkit.entity.Player getPlayer() {
+    return getOwner();
+  }
+
+  @Override
+  public int getContainerSize() {
+    return size;
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return slots.stream().map(Content::get).allMatch(ItemStack::isEmpty);
+  }
+
+  @Override
+  public ItemStack getItem(int index) {
+    return slots.get(index).get();
+  }
+
+  @Override
+  public ItemStack removeItem(int index, int amount) {
+    return slots.get(index).removePartial(amount);
+  }
+
+  @Override
+  public ItemStack removeItemNoUpdate(int index) {
+    return slots.get(index).remove();
+  }
+
+  @Override
+  public void setItem(int index, ItemStack itemStack) {
+    slots.get(index).set(itemStack);
+  }
+
+  @Override
+  public int getMaxStackSize() {
+    return maxStackSize;
+  }
+
+  @Override
+  public void setMaxStackSize(int maxStackSize) {
+    this.maxStackSize = maxStackSize;
+  }
+
+  @Override
+  public void setChanged() {}
+
+  @Override
+  public boolean stillValid(@NotNull Player player) {
+    return true;
+  }
+
+  @Override
+  public @NotNull List<ItemStack> getContents() {
+    NonNullList<ItemStack> contents = NonNullList.withSize(getContainerSize(), ItemStack.EMPTY);
+    for (int i = 0; i < getContainerSize(); ++i) {
+      contents.set(i, getItem(i));
+    }
+    return contents;
+  }
+
+  @Override
+  public void onOpen(CraftHumanEntity viewer) {
+    transaction.add(viewer);
+  }
+
+  @Override
+  public void onClose(CraftHumanEntity viewer) {
+    transaction.remove(viewer);
+  }
+
+  @Override
+  public List<HumanEntity> getViewers() {
+    return transaction;
+  }
+
+  @Override
+  public @NotNull org.bukkit.entity.Player getOwner() {
+    return owner.getBukkitEntity();
+  }
+
+  @Override
+  public Location getLocation() {
+    return owner.getBukkitEntity().getLocation();
+  }
+
+  @Override
+  public void clearContent() {
+    owner.getInventory().clearContent();
+    owner.inventoryMenu.getCraftSlots().clearContent();
+    owner.inventoryMenu.slotsChanged(owner.inventoryMenu.getCraftSlots());
+    owner.containerMenu.setCarried(ItemStack.EMPTY);
+  }
+
+  public @Nullable AbstractContainerMenu createMenu(Player player, int i, boolean viewOnly) {
+    if (player instanceof ServerPlayer serverPlayer) {
+      return new OpenInventoryMenu(this, serverPlayer, i, viewOnly);
+    }
+    return null;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/Placeholders.java

@@ -0,0 +1,184 @@
+package com.lishid.openinv.internal.common.container;
+
+import com.lishid.openinv.internal.common.player.OpenPlayer;
+import net.minecraft.core.Registry;
+import net.minecraft.core.RegistryAccess;
+import net.minecraft.core.component.DataComponents;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.TagParser;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.Unit;
+import net.minecraft.world.item.DyeColor;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+import net.minecraft.world.item.component.CustomModelData;
+import net.minecraft.world.item.component.DyedItemColor;
+import net.minecraft.world.level.GameType;
+import net.minecraft.world.level.ItemLike;
+import net.minecraft.world.level.block.entity.BannerPattern;
+import net.minecraft.world.level.block.entity.BannerPatternLayers;
+import net.minecraft.world.level.block.entity.BannerPatterns;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.craftbukkit.CraftRegistry;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.EnumMap;
+import java.util.List;
+import java.util.Optional;
+
+public final class Placeholders {
+
+  private static final CustomModelData DEFAULT_CUSTOM_MODEL_DATA = new CustomModelData(List.of(), List.of(), List.of("openinv:custom"), List.of());
+  public static final @NotNull EnumMap<GameType, ItemStack> BLOCKED_GAME_TYPE = new EnumMap<>(GameType.class);
+  public static @NotNull ItemStack craftingOutput = defaultCraftingOutput();
+  public static @NotNull ItemStack cursor = defaultCursor();
+  public static @NotNull ItemStack drop = defaultDrop();
+  public static @NotNull ItemStack emptyHelmet = getEmptyArmor(Items.LEATHER_HELMET);
+  public static @NotNull ItemStack emptyChestplate = getEmptyArmor(Items.LEATHER_CHESTPLATE);
+  public static @NotNull ItemStack emptyLeggings = getEmptyArmor(Items.LEATHER_LEGGINGS);
+  public static @NotNull ItemStack emptyBoots = getEmptyArmor(Items.LEATHER_BOOTS);
+  public static @NotNull ItemStack emptyOffHand = getEmptyShield();
+  public static @NotNull ItemStack notSlot = defaultNotSlot();
+  public static @NotNull ItemStack blockedOffline = defaultBlockedOffline();
+
+  static {
+    for (GameType type : GameType.values()) {
+      // Barrier: "Not available - Creative" etc.
+      ItemStack typeItem = new ItemStack(Items.BARRIER);
+      typeItem.set(
+          DataComponents.ITEM_NAME,
+          Component.translatable("options.narrator.notavailable").append(" - ").append(type.getShortDisplayName()));
+      BLOCKED_GAME_TYPE.put(type, typeItem);
+    }
+  }
+
+  public static void load(@NotNull ConfigurationSection section) throws Exception {
+    craftingOutput = parse(section, "crafting-output", craftingOutput);
+    cursor = parse(section, "cursor", cursor);
+    drop = parse(section, "drop", drop);
+    emptyHelmet = parse(section, "empty-helmet", emptyHelmet);
+    emptyChestplate = parse(section, "empty-chestplate", emptyChestplate);
+    emptyLeggings = parse(section, "empty-leggings", emptyLeggings);
+    emptyBoots = parse(section, "empty-boots", emptyBoots);
+    emptyOffHand = parse(section, "empty-off-hand", emptyOffHand);
+    notSlot = parse(section, "not-a-slot", notSlot);
+    blockedOffline = parse(section, "blocked.offline", blockedOffline);
+    BLOCKED_GAME_TYPE.put(GameType.CREATIVE, parse(section, "blocked.creative", BLOCKED_GAME_TYPE.get(GameType.CREATIVE)));
+    BLOCKED_GAME_TYPE.put(GameType.SPECTATOR, parse(section, "blocked.spectator", BLOCKED_GAME_TYPE.get(GameType.SPECTATOR)));
+  }
+
+  private static @NotNull ItemStack parse(
+      @NotNull ConfigurationSection section,
+      @NotNull String path,
+      @NotNull ItemStack defaultStack) throws Exception {
+    String itemText = section.getString(path);
+
+    if (itemText == null) {
+      return defaultStack;
+    }
+
+    CompoundTag compoundTag = TagParser.parseTag(itemText);
+    Optional<ItemStack> parsed = ItemStack.parse(CraftRegistry.getMinecraftRegistry(), compoundTag);
+    return parsed.filter(itemStack -> !itemStack.isEmpty()).orElse(defaultStack);
+  }
+
+  public static ItemStack survivalOnly(@NotNull ServerPlayer serverPlayer) {
+    if (!OpenPlayer.isConnected(serverPlayer.connection)) {
+      return blockedOffline;
+    }
+
+    return BLOCKED_GAME_TYPE.getOrDefault(serverPlayer.gameMode.getGameModeForPlayer(), ItemStack.EMPTY);
+  }
+
+  private static ItemStack defaultCraftingOutput() {
+    // Crafting table: "Crafting"
+    ItemStack itemStack = new ItemStack(Items.CRAFTING_TABLE);
+    itemStack.set(DataComponents.ITEM_NAME, Component.translatable("container.crafting"));
+    itemStack.set(DataComponents.CUSTOM_MODEL_DATA, DEFAULT_CUSTOM_MODEL_DATA);
+    return itemStack;
+  }
+
+  private static ItemStack defaultCursor() {
+    // Cursor-like banner with no tooltip
+    ItemStack itemStack = new ItemStack(Items.WHITE_BANNER);
+    RegistryAccess minecraftRegistry = CraftRegistry.getMinecraftRegistry();
+    Registry<BannerPattern> bannerPatterns = minecraftRegistry.lookupOrThrow(Registries.BANNER_PATTERN);
+    BannerPattern halfDiagBottomRight = bannerPatterns.getOrThrow(BannerPatterns.DIAGONAL_RIGHT).value();
+    BannerPattern downRight = bannerPatterns.getOrThrow(BannerPatterns.STRIPE_DOWNRIGHT).value();
+    BannerPattern border = bannerPatterns.getOrThrow(BannerPatterns.BORDER).value();
+    itemStack.set(DataComponents.BANNER_PATTERNS,
+        new BannerPatternLayers(List.of(
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(halfDiagBottomRight), DyeColor.GRAY),
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(downRight), DyeColor.WHITE),
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(border), DyeColor.GRAY))));
+    itemStack.set(DataComponents.CUSTOM_MODEL_DATA, DEFAULT_CUSTOM_MODEL_DATA);
+    itemStack.set(DataComponents.HIDE_TOOLTIP, Unit.INSTANCE);
+    return itemStack;
+  }
+
+  private static ItemStack defaultDrop() {
+    // Dropper: "Drop Selected Item"
+    ItemStack itemStack = new ItemStack(Items.DROPPER);
+    // Note: translatable component, not keybind component! We want the text identifying the keybind, not the key.
+    itemStack.set(DataComponents.ITEM_NAME, Component.translatable("key.drop"));
+    itemStack.set(DataComponents.CUSTOM_MODEL_DATA, DEFAULT_CUSTOM_MODEL_DATA);
+    return itemStack;
+  }
+
+  private static ItemStack getEmptyArmor(ItemLike item) {
+    // Inventory-background-grey-ish leather armor with no tooltip
+    ItemStack itemStack = new ItemStack(item);
+    DyedItemColor color = new DyedItemColor(0xC8C8C8, false);
+    itemStack.set(DataComponents.DYED_COLOR, color);
+    itemStack.set(DataComponents.HIDE_TOOLTIP, Unit.INSTANCE);
+    itemStack.set(DataComponents.CUSTOM_MODEL_DATA, DEFAULT_CUSTOM_MODEL_DATA);
+    return itemStack;
+  }
+
+  private static ItemStack getEmptyShield() {
+    ItemStack itemStack = new ItemStack(Items.SHIELD);
+    itemStack.set(DataComponents.BASE_COLOR, DyeColor.MAGENTA);
+    RegistryAccess minecraftRegistry = CraftRegistry.getMinecraftRegistry();
+    Registry<BannerPattern> bannerPatterns = minecraftRegistry.lookupOrThrow(Registries.BANNER_PATTERN);
+    BannerPattern halfLeft = bannerPatterns.getOrThrow(BannerPatterns.HALF_VERTICAL).value();
+    BannerPattern topLeft = bannerPatterns.getOrThrow(BannerPatterns.SQUARE_TOP_LEFT).value();
+    BannerPattern topRight = bannerPatterns.getOrThrow(BannerPatterns.SQUARE_TOP_RIGHT).value();
+    BannerPattern bottomLeft = bannerPatterns.getOrThrow(BannerPatterns.SQUARE_BOTTOM_LEFT).value();
+    BannerPattern bottomRight = bannerPatterns.getOrThrow(BannerPatterns.SQUARE_BOTTOM_RIGHT).value();
+    itemStack.set(DataComponents.BANNER_PATTERNS,
+        new BannerPatternLayers(List.of(
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(halfLeft), DyeColor.BLACK),
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(topLeft), DyeColor.MAGENTA),
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(bottomLeft), DyeColor.MAGENTA),
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(topRight), DyeColor.BLACK),
+            new BannerPatternLayers.Layer(bannerPatterns.wrapAsHolder(bottomRight), DyeColor.BLACK))));
+    itemStack.set(DataComponents.HIDE_TOOLTIP, Unit.INSTANCE);
+    itemStack.set(DataComponents.CUSTOM_MODEL_DATA, DEFAULT_CUSTOM_MODEL_DATA);
+    return itemStack;
+  }
+
+  private static ItemStack defaultNotSlot() {
+    // White pane with no tooltip
+    ItemStack itemStack = new ItemStack(Items.WHITE_STAINED_GLASS_PANE);
+    itemStack.set(DataComponents.HIDE_TOOLTIP, Unit.INSTANCE);
+    itemStack.set(DataComponents.CUSTOM_MODEL_DATA, DEFAULT_CUSTOM_MODEL_DATA);
+    return itemStack;
+  }
+
+  private static ItemStack defaultBlockedOffline() {
+    // Barrier: "Not available - Offline"
+    ItemStack itemStack = new ItemStack(Items.BARRIER);
+    itemStack.set(DataComponents.ITEM_NAME,
+        Component.translatable("options.narrator.notavailable")
+            .append(Component.literal(" - "))
+            .append(Component.translatable("gui.socialInteractions.status_offline")));
+    return itemStack;
+  }
+
+  private Placeholders() {
+    throw new IllegalStateException("Cannot create instance of utility class.");
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/bukkit/OpenDummyInventory.java

@@ -0,0 +1,172 @@
+package com.lishid.openinv.internal.common.container.bukkit;
+
+import com.lishid.openinv.internal.ViewOnly;
+import net.minecraft.world.Container;
+import org.bukkit.Material;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.ListIterator;
+
+/**
+ * A locked down "empty" inventory that rejects plugin interaction.
+ */
+public class OpenDummyInventory extends CraftInventory implements ViewOnly {
+
+  private final InventoryType type;
+
+  public OpenDummyInventory(Container inventory, InventoryType type) {
+    super(inventory);
+    this.type = type;
+  }
+
+  @Override
+  public @NotNull InventoryType getType() {
+    return type;
+  }
+
+  @Override
+  public @Nullable ItemStack getItem(int index) {
+    return null;
+  }
+
+  @Override
+  public void setItem(int index, @Nullable ItemStack item) {
+
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public @NotNull HashMap<Integer, ItemStack> addItem(@NotNull ItemStack... items) throws IllegalArgumentException {
+    return arrayToHashMap(items);
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public @NotNull HashMap<Integer, ItemStack> removeItem(@NotNull ItemStack... items) throws IllegalArgumentException {
+    return arrayToHashMap(items);
+  }
+
+  @SuppressWarnings("NonApiType")
+  private static @NotNull HashMap<Integer, ItemStack> arrayToHashMap(@NotNull ItemStack[] items) {
+    HashMap<Integer, ItemStack> ignored = new HashMap<>();
+    for (int index = 0; index < items.length; ++index) {
+      ignored.put(index, items[index]);
+    }
+    return ignored;
+  }
+
+  @Override
+  public ItemStack[] getContents() {
+    return new ItemStack[getSize()];
+  }
+
+  @Override
+  public void setContents(@NotNull ItemStack[] items) throws IllegalArgumentException {
+
+  }
+
+  @Override
+  public @NotNull ItemStack[] getStorageContents() {
+    return new ItemStack[getSize()];
+  }
+
+  @Override
+  public void setStorageContents(@NotNull ItemStack[] items) throws IllegalArgumentException {
+
+  }
+
+  @Override
+  public boolean contains(@NotNull Material material) throws IllegalArgumentException {
+    return false;
+  }
+
+  @Override
+  public boolean contains(@Nullable ItemStack item) {
+    return false;
+  }
+
+  @Override
+  public boolean contains(@NotNull Material material, int amount) throws IllegalArgumentException {
+    return false;
+  }
+
+  @Override
+  public boolean contains(@Nullable ItemStack item, int amount) {
+    return false;
+  }
+
+  @Override
+  public boolean containsAtLeast(@Nullable ItemStack item, int amount) {
+    return false;
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public @NotNull HashMap<Integer, ItemStack> all(
+      @NotNull Material material) throws IllegalArgumentException {
+    return new HashMap<>();
+  }
+
+  @SuppressWarnings("NonApiType")
+  @Override
+  public @NotNull HashMap<Integer, ItemStack> all(@Nullable ItemStack item) {
+    return new HashMap<>();
+  }
+
+  @Override
+  public int first(@NotNull Material material) throws IllegalArgumentException {
+    return -1;
+  }
+
+  @Override
+  public int first(@NotNull ItemStack item) {
+    return -1;
+  }
+
+  @Override
+  public int firstEmpty() {
+    return -1;
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return true;
+  }
+
+  @Override
+  public void remove(@NotNull Material material) throws IllegalArgumentException {
+
+  }
+
+  @Override
+  public void remove(@NotNull ItemStack item) {
+
+  }
+
+  @Override
+  public void clear(int index) {
+
+  }
+
+  @Override
+  public void clear() {
+
+  }
+
+  @Override
+  public @NotNull ListIterator<ItemStack> iterator() {
+    return Collections.emptyListIterator();
+  }
+
+  @Override
+  public @NotNull ListIterator<ItemStack> iterator(int index) {
+    return Collections.emptyListIterator();
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/bukkit/OpenDummyPlayerInventory.java

@@ -0,0 +1,134 @@
+package com.lishid.openinv.internal.common.container.bukkit;
+
+import net.minecraft.world.Container;
+import org.bukkit.Material;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.EquipmentSlot;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.PlayerInventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class OpenDummyPlayerInventory extends OpenDummyInventory implements PlayerInventory {
+
+  public OpenDummyPlayerInventory(Container inventory) {
+    super(inventory, InventoryType.PLAYER);
+  }
+
+  @Override
+  public HumanEntity getHolder() {
+    return (HumanEntity) super.getHolder();
+  }
+
+  @Override
+  public @NotNull ItemStack[] getArmorContents() {
+    return new ItemStack[4];
+  }
+
+  @Override
+  public @NotNull ItemStack[] getExtraContents() {
+    return new ItemStack[4];
+  }
+
+  @Override
+  public @Nullable ItemStack getHelmet() {
+    return null;
+  }
+
+  @Override
+  public @Nullable ItemStack getChestplate() {
+    return null;
+  }
+
+  @Override
+  public @Nullable ItemStack getLeggings() {
+    return null;
+  }
+
+  @Override
+  public @Nullable ItemStack getBoots() {
+    return null;
+  }
+
+  @Override
+  public void setItem(@NotNull EquipmentSlot slot, @Nullable ItemStack item) {
+
+  }
+
+  @Override
+  public @Nullable ItemStack getItem(@NotNull EquipmentSlot slot) {
+    return null;
+  }
+
+  @Override
+  public void setArmorContents(@Nullable ItemStack[] items) {
+
+  }
+
+  @Override
+  public void setExtraContents(@Nullable ItemStack[] items) {
+
+  }
+
+  @Override
+  public void setHelmet(@Nullable ItemStack helmet) {
+
+  }
+
+  @Override
+  public void setChestplate(@Nullable ItemStack chestplate) {
+
+  }
+
+  @Override
+  public void setLeggings(@Nullable ItemStack leggings) {
+
+  }
+
+  @Override
+  public void setBoots(@Nullable ItemStack boots) {
+
+  }
+
+  @Override
+  public @NotNull ItemStack getItemInMainHand() {
+    return new ItemStack(Material.AIR);
+  }
+
+  @Override
+  public void setItemInMainHand(@Nullable ItemStack item) {
+
+  }
+
+  @Override
+  public @NotNull ItemStack getItemInOffHand() {
+    return new ItemStack(Material.AIR);
+  }
+
+  @Override
+  public void setItemInOffHand(@Nullable ItemStack item) {
+
+  }
+
+  @Override
+  public @NotNull ItemStack getItemInHand() {
+    return new ItemStack(Material.AIR);
+  }
+
+  @Override
+  public void setItemInHand(@Nullable ItemStack stack) {
+
+  }
+
+  @Override
+  public int getHeldItemSlot() {
+    return 0;
+  }
+
+  @Override
+  public void setHeldItemSlot(int slot) {
+
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/bukkit/OpenPlayerInventory.java

@@ -0,0 +1,221 @@
+package com.lishid.openinv.internal.common.container.bukkit;
+
+import com.google.common.base.Preconditions;
+import com.lishid.openinv.internal.common.container.OpenInventory;
+import net.minecraft.core.NonNullList;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Inventory;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.entity.Player;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.PlayerInventory;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class OpenPlayerInventory extends CraftInventory implements PlayerInventory {
+
+  public OpenPlayerInventory(@NotNull OpenInventory inventory) {
+    super(inventory);
+  }
+
+  @Override
+  public @NotNull OpenInventory getInventory() {
+    return (OpenInventory) super.getInventory();
+  }
+
+  @Override
+  public ItemStack[] getContents() {
+    return asCraftMirror(getInventory().getOwnerHandle().getInventory().getContents());
+  }
+
+  @Override
+  public void setContents(ItemStack[] items) {
+    Inventory internal = getInventory().getOwnerHandle().getInventory();
+    int size = internal.getContainerSize();
+    Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
+
+    for (int index = 0; index < size; ++index) {
+      if (index < items.length) {
+        internal.setItem(index, CraftItemStack.asNMSCopy(items[index]));
+      } else {
+        internal.setItem(index, net.minecraft.world.item.ItemStack.EMPTY);
+      }
+    }
+  }
+
+  @Override
+  public ItemStack[] getStorageContents() {
+    return asCraftMirror(getInventory().getOwnerHandle().getInventory().items);
+  }
+
+  @Override
+  public void setStorageContents(ItemStack[] items) throws IllegalArgumentException {
+    NonNullList<net.minecraft.world.item.ItemStack> list = getInventory().getOwnerHandle().getInventory().items;
+    int size = list.size();
+    Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
+    for (int index = 0; index < items.length; ++index) {
+      list.set(index, CraftItemStack.asNMSCopy(items[index]));
+    }
+  }
+
+  @Override
+  public @NotNull InventoryType getType() {
+    return InventoryType.PLAYER;
+  }
+
+  @Override
+  public @NotNull Player getHolder() {
+    return getInventory().getOwner();
+  }
+
+  @Override
+  public @NotNull ItemStack[] getArmorContents() {
+    return asCraftMirror(getInventory().getOwnerHandle().getInventory().armor);
+  }
+
+  @Override
+  public void setArmorContents(@Nullable ItemStack[] items) {
+    NonNullList<net.minecraft.world.item.ItemStack> list = getInventory().getOwnerHandle().getInventory().armor;
+    int size = list.size();
+    Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
+    for (int index = 0; index < items.length; ++index) {
+      list.set(index, CraftItemStack.asNMSCopy(items[index]));
+    }
+  }
+
+  @Override
+  public @NotNull ItemStack[] getExtraContents() {
+    return asCraftMirror(getInventory().getOwnerHandle().getInventory().offhand);
+  }
+
+  @Override
+  public void setExtraContents(@Nullable ItemStack[] items) {
+    NonNullList<net.minecraft.world.item.ItemStack> list = getInventory().getOwnerHandle().getInventory().offhand;
+    int size = list.size();
+    Preconditions.checkArgument(items.length <= size, "items.length must be <= %s", size);
+    for (int index = 0; index < items.length; ++index) {
+      list.set(index, CraftItemStack.asNMSCopy(items[index]));
+    }
+  }
+
+  @Override
+  public @Nullable ItemStack getHelmet() {
+    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory()
+        .getArmor(EquipmentSlot.HEAD.getIndex()));
+  }
+
+  @Override
+  public void setHelmet(@Nullable ItemStack helmet) {
+    getInventory().getOwnerHandle().getInventory().armor
+        .set(EquipmentSlot.HEAD.getIndex(), CraftItemStack.asNMSCopy(helmet));
+  }
+
+  @Override
+  public @Nullable ItemStack getChestplate() {
+    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory()
+        .getArmor(EquipmentSlot.HEAD.getIndex()));
+  }
+
+  @Override
+  public void setChestplate(@Nullable ItemStack chestplate) {
+    getInventory().getOwnerHandle().getInventory().armor
+        .set(EquipmentSlot.CHEST.getIndex(), CraftItemStack.asNMSCopy(chestplate));
+  }
+
+  @Override
+  public @Nullable ItemStack getLeggings() {
+    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory()
+        .getArmor(EquipmentSlot.LEGS.getIndex()));
+  }
+
+  @Override
+  public void setLeggings(@Nullable ItemStack leggings) {
+    getInventory().getOwnerHandle().getInventory().armor
+        .set(EquipmentSlot.LEGS.getIndex(), CraftItemStack.asNMSCopy(leggings));
+  }
+
+  @Override
+  public @Nullable ItemStack getBoots() {
+    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory()
+        .getArmor(EquipmentSlot.FEET.getIndex()));
+  }
+
+  @Override
+  public void setBoots(@Nullable ItemStack boots) {
+    getInventory().getOwnerHandle().getInventory().armor
+        .set(EquipmentSlot.FEET.getIndex(), CraftItemStack.asNMSCopy(boots));
+  }
+
+  @Override
+  public @NotNull ItemStack getItemInMainHand() {
+    Inventory internal = getInventory().getOwnerHandle().getInventory();
+    return CraftItemStack.asCraftMirror(internal.getItem(internal.selected));
+  }
+
+  @Override
+  public void setItemInMainHand(@Nullable ItemStack item) {
+    Inventory internal = getInventory().getOwnerHandle().getInventory();
+    internal.setItem(internal.selected, CraftItemStack.asNMSCopy(item));
+  }
+
+  @Override
+  public @NotNull ItemStack getItemInOffHand() {
+    return CraftItemStack.asCraftMirror(getInventory().getOwnerHandle().getInventory().offhand.getFirst());
+  }
+
+  @Override
+  public void setItemInOffHand(@Nullable ItemStack item) {
+    getInventory().getOwnerHandle().getInventory().offhand.set(0, CraftItemStack.asNMSCopy(item));
+  }
+
+  @Override
+  public @NotNull ItemStack getItemInHand() {
+    return getItemInMainHand();
+  }
+
+  @Override
+  public void setItemInHand(@Nullable ItemStack stack) {
+    setItemInMainHand(stack);
+  }
+
+  @Override
+  public int getHeldItemSlot() {
+    Inventory internal = getInventory().getOwnerHandle().getInventory();
+    return internal.items.size() - 9 + internal.selected;
+  }
+
+  @Override
+  public void setHeldItemSlot(int slot) {
+    slot %= 9;
+    getInventory().getOwnerHandle().getInventory().selected = slot;
+  }
+
+  @Override
+  public @Nullable ItemStack getItem(@NotNull org.bukkit.inventory.EquipmentSlot slot) {
+    return switch (slot) {
+      case HAND -> getItemInMainHand();
+      case OFF_HAND -> getItemInOffHand();
+      case FEET -> getBoots();
+      case LEGS -> getLeggings();
+      case CHEST -> getChestplate();
+      case HEAD -> getHelmet();
+      default -> throw new IllegalArgumentException("Unsupported EquipmentSlot " + slot);
+    };
+  }
+
+  @Override
+  public void setItem(@NotNull org.bukkit.inventory.EquipmentSlot slot, @Nullable ItemStack item) {
+    switch (slot) {
+      case HAND -> setItemInMainHand(item);
+      case OFF_HAND -> setItemInOffHand(item);
+      case FEET -> setBoots(item);
+      case LEGS -> setLeggings(item);
+      case CHEST -> setChestplate(item);
+      case HEAD -> setHelmet(item);
+      default -> throw new IllegalArgumentException("Unsupported EquipmentSlot " + slot);
+    }
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/bukkit/OpenPlayerInventorySelf.java

@@ -0,0 +1,26 @@
+package com.lishid.openinv.internal.common.container.bukkit;
+
+import com.lishid.openinv.internal.common.container.OpenInventory;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+public class OpenPlayerInventorySelf extends OpenPlayerInventory {
+
+  private final int offset;
+
+  public OpenPlayerInventorySelf(@NotNull OpenInventory inventory, int offset) {
+    super(inventory);
+    this.offset = offset;
+  }
+
+  @Override
+  public ItemStack getItem(int index) {
+    return super.getItem(offset + index);
+  }
+
+  @Override
+  public void setItem(int index, ItemStack item) {
+    super.setItem(offset + index, item);
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/menu/OpenChestMenu.java

@@ -0,0 +1,477 @@
+package com.lishid.openinv.internal.common.container.menu;
+
+import com.google.common.base.Suppliers;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.InternalOwned;
+import com.lishid.openinv.internal.common.container.bukkit.OpenDummyInventory;
+import com.lishid.openinv.internal.common.container.slot.SlotPlaceholder;
+import com.lishid.openinv.internal.common.container.slot.SlotViewOnly;
+import it.unimi.dsi.fastutil.ints.IntArrayList;
+import it.unimi.dsi.fastutil.ints.IntList;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.ClickType;
+import net.minecraft.world.inventory.ContainerData;
+import net.minecraft.world.inventory.ContainerListener;
+import net.minecraft.world.inventory.ContainerSynchronizer;
+import net.minecraft.world.inventory.DataSlot;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftInventoryView;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Supplier;
+
+/**
+ * An extension of {@link AbstractContainerMenu} that supports {@link SlotPlaceholder placeholders}.
+ */
+public abstract class OpenChestMenu<T extends Container & ISpecialInventory & InternalOwned<ServerPlayer>>
+    extends AbstractContainerMenu {
+
+  protected static final int BOTTOM_INVENTORY_SIZE = 36;
+
+  protected final T container;
+  protected final ServerPlayer viewer;
+  protected final boolean viewOnly;
+  protected final boolean ownContainer;
+  protected final int topSize;
+  private CraftInventoryView<OpenChestMenu<T>, Inventory> bukkitEntity;
+  // Syncher fields
+  private @Nullable ContainerSynchronizer synchronizer;
+  private final List<DataSlot> dataSlots = new ArrayList<>();
+  private final IntList remoteDataSlots = new IntArrayList();
+  private final List<ContainerListener> containerListeners = new ArrayList<>();
+  private ItemStack remoteCarried = ItemStack.EMPTY;
+  private boolean suppressRemoteUpdates;
+
+  protected OpenChestMenu(
+      @NotNull MenuType<ChestMenu> type,
+      int containerCounter,
+      @NotNull T container,
+      @NotNull ServerPlayer viewer,
+      boolean viewOnly) {
+    super(type, containerCounter);
+    this.container = container;
+    this.viewer = viewer;
+    this.viewOnly = viewOnly;
+    ownContainer = container.getOwnerHandle().equals(viewer);
+    topSize = getTopSize(viewer);
+
+    preSlotSetup();
+
+    int upperRows = topSize / 9;
+    // View's upper inventory - our container
+    for (int row = 0; row < upperRows; ++row) {
+      for (int col = 0; col < 9; ++col) {
+        // x and y for client purposes, but hey, we're thorough here.
+        // Adapted from net.minecraft.world.inventory.ChestMenu
+        int x = 8 + col * 18;
+        int y = 18 + row * 18;
+        int index = row * 9 + col;
+
+        // Guard against weird inventory sizes.
+        if (index >= container.getContainerSize()) {
+          addSlot(new SlotViewOnly(container, index, x, y));
+          continue;
+        }
+
+        Slot slot = getUpperSlot(index, x, y);
+
+        addSlot(slot);
+      }
+    }
+
+    // View's lower inventory - viewer inventory
+    int playerInvPad = (upperRows - 4) * 18;
+    for (int row = 0; row < 3; ++row) {
+      for (int col = 0; col < 9; ++col) {
+        int x = 8 + col * 18;
+        int y = playerInvPad + row * 18 + 103;
+        addSlot(new Slot(viewer.getInventory(), row * 9 + col + 9, x, y));
+      }
+    }
+    // Hotbar
+    for (int col = 0; col < 9; ++col) {
+      int x = 8 + col * 18;
+      int y = playerInvPad + 161;
+      addSlot(new Slot(viewer.getInventory(), col, x, y));
+    }
+  }
+
+  public static @NotNull MenuType<ChestMenu> getChestMenuType(int inventorySize) {
+    inventorySize = ((int) Math.ceil(inventorySize / 9.0)) * 9;
+    return switch (inventorySize) {
+      case 9 -> MenuType.GENERIC_9x1;
+      case 18 -> MenuType.GENERIC_9x2;
+      case 27 -> MenuType.GENERIC_9x3;
+      case 36 -> MenuType.GENERIC_9x4;
+      case 45 -> MenuType.GENERIC_9x5;
+      case 54 -> MenuType.GENERIC_9x6;
+      default -> throw new IllegalArgumentException("Inventory size unsupported: " + inventorySize);
+    };
+  }
+
+  protected void preSlotSetup() {}
+
+  protected @NotNull Slot getUpperSlot(int index, int x, int y) {
+    Slot slot = new Slot(container, index, x, y);
+    if (viewOnly) {
+      return SlotViewOnly.wrap(slot);
+    }
+    return slot;
+  }
+
+
+  @Override
+  public final @NotNull CraftInventoryView<OpenChestMenu<T>, Inventory> getBukkitView() {
+    if (bukkitEntity == null) {
+      bukkitEntity = createBukkitEntity();
+    }
+
+    return bukkitEntity;
+  }
+
+  protected @NotNull CraftInventoryView<OpenChestMenu<T>, Inventory> createBukkitEntity() {
+    Inventory top;
+    if (viewOnly) {
+      top = new OpenDummyInventory(container, container.getBukkitType());
+    } else {
+      top = container.getBukkitInventory();
+    }
+    return new CraftInventoryView<>(viewer.getBukkitEntity(), top, this) {
+      @Override
+      public @Nullable Inventory getInventory(int rawSlot) {
+        if (viewOnly) {
+          return null;
+        }
+        return super.getInventory(rawSlot);
+      }
+
+      @Override
+      public int convertSlot(int rawSlot) {
+        if (viewOnly) {
+          return InventoryView.OUTSIDE;
+        }
+        return super.convertSlot(rawSlot);
+      }
+
+      @Override
+      public @NotNull InventoryType.SlotType getSlotType(int slot) {
+        if (viewOnly) {
+          return InventoryType.SlotType.OUTSIDE;
+        }
+        return super.getSlotType(slot);
+      }
+    };
+  }
+
+  private int getTopSize(ServerPlayer viewer) {
+    MenuType<?> menuType = getType();
+    if (menuType == MenuType.GENERIC_9x1) {
+      return 9;
+    } else if (menuType == MenuType.GENERIC_9x2) {
+      return 18;
+    } else if (menuType == MenuType.GENERIC_9x3) {
+      return 27;
+    } else if (menuType == MenuType.GENERIC_9x4) {
+      return 36;
+    } else if (menuType == MenuType.GENERIC_9x5) {
+      return 45;
+    } else if (menuType == MenuType.GENERIC_9x6) {
+      return 54;
+    }
+    // This is a bit gross, but allows us a safe fallthrough.
+    return menuType.create(-1, viewer.getInventory()).slots.size() - BOTTOM_INVENTORY_SIZE;
+  }
+
+  /**
+   * Reimplementation of {@link AbstractContainerMenu#moveItemStackTo(ItemStack, int, int, boolean)} that ignores fake
+   * slots and respects {@link Slot#hasItem()}.
+   *
+   * @param itemStack the stack to quick-move
+   * @param rangeLow the start of the range of slots that can be moved to, inclusive
+   * @param rangeHigh the end of the range of slots that can be moved to, exclusive
+   * @param topDown whether to start at the top of the range or bottom
+   * @return whether the stack was modified as a result of being quick-moved
+   */
+  @Override
+  protected boolean moveItemStackTo(ItemStack itemStack, int rangeLow, int rangeHigh, boolean topDown) {
+    boolean modified = false;
+    boolean stackable = itemStack.isStackable();
+    Slot firstEmpty = null;
+
+    for (int index = topDown ? rangeHigh - 1 : rangeLow;
+         !itemStack.isEmpty() && (topDown ? index >= rangeLow : index < rangeHigh);
+         index += topDown ? -1 : 1
+    ) {
+      Slot slot = slots.get(index);
+      // If the slot cannot be added to, check the next slot.
+      if (slot.isFake() || !slot.mayPlace(itemStack)) {
+        continue;
+      }
+
+      if (slot.hasItem()) {
+        // If the item isn't stackable, check the next slot.
+        if (!stackable) {
+          continue;
+        }
+        // Otherwise, add as many as we can from our stack to the slot.
+        modified |= addToExistingStack(itemStack, slot);
+      } else {
+        // If this is the first empty slot, keep track of it for later use.
+        if (firstEmpty == null) {
+          firstEmpty = slot;
+        }
+        // If the item isn't stackable, we've located the slot we're adding it to, so we're done.
+        if (!stackable) {
+          break;
+        }
+      }
+    }
+
+    // If the item hasn't been fully added yet, add as many as we can to the first open slot.
+    if (!itemStack.isEmpty() && firstEmpty != null) {
+      firstEmpty.setByPlayer(itemStack.split(Math.min(itemStack.getCount(), firstEmpty.getMaxStackSize(itemStack))));
+      firstEmpty.setChanged();
+      modified = true;
+    }
+
+    return modified;
+  }
+
+  private static boolean addToExistingStack(ItemStack itemStack, Slot slot) {
+    ItemStack existing = slot.getItem();
+
+    // If the items aren't the same, we can't add our item.
+    if (!ItemStack.isSameItemSameComponents(itemStack, existing)) {
+      return false;
+    }
+
+    int max = slot.getMaxStackSize(existing);
+    int existingCount = existing.getCount();
+
+    // If the stack is already full, we can't add more.
+    if (existingCount >= max) {
+      return false;
+    }
+
+    int total = existingCount + itemStack.getCount();
+
+    // If the existing item can accept the entirety of our item, we're done!
+    if (total <= max) {
+      itemStack.setCount(0);
+      existing.setCount(total);
+      slot.setChanged();
+      return true;
+    }
+
+    // Otherwise, add as many as we can.
+    itemStack.shrink(max - existingCount);
+    existing.setCount(max);
+    slot.setChanged();
+    return true;
+  }
+
+  @Override
+  public void clicked(int i, int j, @NotNull ClickType clickType, @NotNull Player player) {
+    if (viewOnly) {
+      if (clickType == ClickType.QUICK_CRAFT) {
+        sendAllDataToRemote();
+      }
+      return;
+    }
+    super.clicked(i, j, clickType, player);
+  }
+
+  @Override
+  public boolean stillValid(@NotNull Player player) {
+    return true;
+  }
+
+  // Overrides from here on are purely to modify the sync process to send placeholder items.
+  @Override
+  protected @NotNull Slot addSlot(@NotNull Slot slot) {
+    slot.index = this.slots.size();
+    this.slots.add(slot);
+    this.lastSlots.add(ItemStack.EMPTY);
+    this.remoteSlots.add(ItemStack.EMPTY);
+    return slot;
+  }
+
+  @Override
+  protected @NotNull DataSlot addDataSlot(@NotNull DataSlot dataSlot) {
+    this.dataSlots.add(dataSlot);
+    this.remoteDataSlots.add(0);
+    return dataSlot;
+  }
+
+  @Override
+  protected void addDataSlots(ContainerData containerData) {
+    for (int i = 0; i < containerData.getCount(); i++) {
+      this.addDataSlot(DataSlot.forContainer(containerData, i));
+    }
+  }
+
+  @Override
+  public void addSlotListener(@NotNull ContainerListener containerListener) {
+    if (!this.containerListeners.contains(containerListener)) {
+      this.containerListeners.add(containerListener);
+      this.broadcastChanges();
+    }
+  }
+
+  @Override
+  public void setSynchronizer(@NotNull ContainerSynchronizer containerSynchronizer) {
+    this.synchronizer = containerSynchronizer;
+    this.sendAllDataToRemote();
+  }
+
+  @Override
+  public void sendAllDataToRemote() {
+    for (int index = 0; index < slots.size(); ++index) {
+      Slot slot = slots.get(index);
+      this.remoteSlots.set(index, (slot instanceof SlotPlaceholder placeholder ? placeholder.getOrDefault() : slot.getItem()).copy());
+    }
+
+    remoteCarried = getCarried().copy();
+
+    for (int index = 0; index < this.dataSlots.size(); ++index) {
+      this.remoteDataSlots.set(index, this.dataSlots.get(index).get());
+    }
+
+    if (this.synchronizer != null) {
+      this.synchronizer.sendInitialData(this, this.remoteSlots, this.remoteCarried, this.remoteDataSlots.toIntArray());
+    }
+  }
+
+  @Override
+  public void broadcastCarriedItem() {
+    this.remoteCarried = this.getCarried().copy();
+    if (this.synchronizer != null) {
+      this.synchronizer.sendCarriedChange(this, this.remoteCarried);
+    }
+  }
+
+  @Override
+  public void removeSlotListener(@NotNull ContainerListener containerListener) {
+    this.containerListeners.remove(containerListener);
+  }
+
+  @Override
+  public void broadcastChanges() {
+    for (int index = 0; index < this.slots.size(); ++index) {
+      Slot slot = this.slots.get(index);
+      ItemStack itemstack = slot instanceof SlotPlaceholder placeholder ? placeholder.getOrDefault() : slot.getItem();
+      Supplier<ItemStack> supplier = Suppliers.memoize(itemstack::copy);
+      this.triggerSlotListeners(index, itemstack, supplier);
+      this.synchronizeSlotToRemote(index, itemstack, supplier);
+    }
+
+    this.synchronizeCarriedToRemote();
+
+    for (int index = 0; index < this.dataSlots.size(); ++index) {
+      DataSlot dataSlot = this.dataSlots.get(index);
+      int j = dataSlot.get();
+      if (dataSlot.checkAndClearUpdateFlag()) {
+        this.updateDataSlotListeners(index, j);
+      }
+
+      this.synchronizeDataSlotToRemote(index, j);
+    }
+  }
+
+  @Override
+  public void broadcastFullState() {
+    for (int index = 0; index < this.slots.size(); ++index) {
+      ItemStack itemstack = this.slots.get(index).getItem();
+      this.triggerSlotListeners(index, itemstack, itemstack::copy);
+    }
+
+    for (int index = 0; index < this.dataSlots.size(); ++index) {
+      DataSlot containerproperty = this.dataSlots.get(index);
+      if (containerproperty.checkAndClearUpdateFlag()) {
+        this.updateDataSlotListeners(index, containerproperty.get());
+      }
+    }
+
+    this.sendAllDataToRemote();
+  }
+
+  private void updateDataSlotListeners(int i, int j) {
+    for (ContainerListener containerListener : this.containerListeners) {
+      containerListener.dataChanged(this, i, j);
+    }
+  }
+
+  private void triggerSlotListeners(int index, ItemStack itemStack, Supplier<ItemStack> supplier) {
+    ItemStack itemStack1 = this.lastSlots.get(index);
+    if (!ItemStack.matches(itemStack1, itemStack)) {
+      ItemStack itemStack2 = supplier.get();
+      this.lastSlots.set(index, itemStack2);
+
+      for (ContainerListener containerListener : this.containerListeners) {
+        containerListener.slotChanged(this, index, itemStack2);
+      }
+    }
+  }
+
+  private void synchronizeSlotToRemote(int i, ItemStack itemStack, Supplier<ItemStack> supplier) {
+    if (!this.suppressRemoteUpdates) {
+      ItemStack itemStack1 = this.remoteSlots.get(i);
+      if (!ItemStack.matches(itemStack1, itemStack)) {
+        ItemStack itemstack2 = supplier.get();
+        this.remoteSlots.set(i, itemstack2);
+        if (this.synchronizer != null) {
+          this.synchronizer.sendSlotChange(this, i, itemstack2);
+        }
+      }
+    }
+  }
+
+  private void synchronizeDataSlotToRemote(int index, int value) {
+    if (!this.suppressRemoteUpdates) {
+      int existing = this.remoteDataSlots.getInt(index);
+      if (existing != value) {
+        this.remoteDataSlots.set(index, value);
+        if (this.synchronizer != null) {
+          this.synchronizer.sendDataChange(this, index, value);
+        }
+      }
+    }
+  }
+
+  private void synchronizeCarriedToRemote() {
+    if (!this.suppressRemoteUpdates && !ItemStack.matches(this.getCarried(), this.remoteCarried)) {
+      this.remoteCarried = this.getCarried().copy();
+      if (this.synchronizer != null) {
+        this.synchronizer.sendCarriedChange(this, this.remoteCarried);
+      }
+    }
+  }
+
+  @Override
+  public void setRemoteCarried(ItemStack itemstack) {
+    this.remoteCarried = itemstack.copy();
+  }
+
+  @Override
+  public void suppressRemoteUpdates() {
+    this.suppressRemoteUpdates = true;
+  }
+
+  @Override
+  public void resumeRemoteUpdates() {
+    this.suppressRemoteUpdates = false;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/menu/OpenEnderChestMenu.java

@@ -0,0 +1,53 @@
+package com.lishid.openinv.internal.common.container.menu;
+
+import com.lishid.openinv.internal.common.container.OpenEnderChest;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+public class OpenEnderChestMenu extends OpenChestMenu<OpenEnderChest> {
+
+  public OpenEnderChestMenu(
+      @NotNull OpenEnderChest enderChest,
+      @NotNull ServerPlayer viewer,
+      int containerId,
+      boolean viewOnly) {
+    super(getChestMenuType(enderChest.getContainerSize()), containerId, enderChest, viewer, viewOnly);
+  }
+
+  @Override
+  public @NotNull ItemStack quickMoveStack(@NotNull Player player, int index) {
+    if (viewOnly) {
+      return ItemStack.EMPTY;
+    }
+
+    // See ChestMenu
+    Slot slot = this.slots.get(index);
+
+    if (slot.isFake() || !slot.hasItem()) {
+      return ItemStack.EMPTY;
+    }
+
+    ItemStack itemStack = slot.getItem();
+    ItemStack original = itemStack.copy();
+
+    if (index < topSize) {
+      if (!this.moveItemStackTo(itemStack, topSize, this.slots.size(), true)) {
+        return ItemStack.EMPTY;
+      }
+    } else if (!this.moveItemStackTo(itemStack, 0, topSize, false)) {
+      return ItemStack.EMPTY;
+    }
+
+    if (itemStack.isEmpty()) {
+      slot.setByPlayer(ItemStack.EMPTY);
+    } else {
+      slot.setChanged();
+    }
+
+    return original;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/menu/OpenInventoryMenu.java

@@ -0,0 +1,262 @@
+package com.lishid.openinv.internal.common.container.menu;
+
+import com.google.common.base.Preconditions;
+import com.lishid.openinv.internal.common.container.OpenInventory;
+import com.lishid.openinv.internal.common.container.bukkit.OpenDummyPlayerInventory;
+import com.lishid.openinv.internal.common.container.bukkit.OpenPlayerInventorySelf;
+import com.lishid.openinv.internal.common.container.slot.ContentDrop;
+import com.lishid.openinv.internal.common.container.slot.ContentEquipment;
+import com.lishid.openinv.internal.common.container.slot.SlotViewOnly;
+import com.lishid.openinv.util.Permissions;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.craftbukkit.inventory.CraftInventoryView;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class OpenInventoryMenu extends OpenChestMenu<OpenInventory> {
+
+  private int offset;
+
+  public OpenInventoryMenu(OpenInventory inventory, ServerPlayer viewer, int i, boolean viewOnly) {
+    super(getMenuType(inventory, viewer), i, inventory, viewer, viewOnly);
+  }
+
+  private static MenuType<ChestMenu> getMenuType(OpenInventory inventory, ServerPlayer viewer) {
+    int size = inventory.getContainerSize();
+    // Disallow duplicate access to own main inventory contents.
+    if (inventory.getOwnerHandle().equals(viewer)) {
+      size -= viewer.getInventory().items.size();
+      size = ((int) Math.ceil(size / 9.0)) * 9;
+    }
+
+    return getChestMenuType(size);
+  }
+
+  @Override
+  protected void preSlotSetup() {
+    offset = ownContainer ? viewer.getInventory().items.size() : 0;
+  }
+
+  @Override
+  protected @NotNull Slot getUpperSlot(int index, int x, int y) {
+    index += offset;
+    Slot slot = container.getMenuSlot(index, x, y);
+
+    // If the slot cannot be interacted with there's nothing to configure.
+    if (slot.getClass().equals(SlotViewOnly.class)) {
+      return slot;
+    }
+
+    // Remove drop slot if viewer is not allowed to use it.
+    if (slot instanceof ContentDrop.SlotDrop
+        && (viewOnly || !Permissions.INVENTORY_SLOT_DROP.hasPermission(viewer.getBukkitEntity()))) {
+      return new SlotViewOnly(container, index, x, y);
+    }
+
+    if (slot instanceof ContentEquipment.SlotEquipment equipment) {
+      if (viewOnly) {
+        return SlotViewOnly.wrap(slot);
+      }
+
+      Permissions perm = switch (equipment.getEquipmentSlot()) {
+        case HEAD -> Permissions.INVENTORY_SLOT_HEAD_ANY;
+        case CHEST -> Permissions.INVENTORY_SLOT_CHEST_ANY;
+        case LEGS -> Permissions.INVENTORY_SLOT_LEGS_ANY;
+        case FEET -> Permissions.INVENTORY_SLOT_FEET_ANY;
+        // Off-hand can hold anything, not just equipment.
+        default -> null;
+      };
+
+      // If the viewer doesn't have permission, only allow equipment the viewee can equip in the slot.
+      if (perm != null && !perm.hasPermission(viewer.getBukkitEntity())) {
+        equipment.onlyEquipmentFor(container.getOwnerHandle());
+      }
+
+      // Equipment slots are a core part of the inventory, so they will always be shown.
+      return slot;
+    }
+
+    // When viewing own inventory, only allow access to equipment and drop slots (equipment allowed above).
+    if (ownContainer && !(slot instanceof ContentDrop.SlotDrop)) {
+      return new SlotViewOnly(container, index, x, y);
+    }
+
+    if (viewOnly) {
+      return SlotViewOnly.wrap(slot);
+    }
+
+    return slot;
+  }
+
+  @Override
+  protected @NotNull CraftInventoryView<OpenChestMenu<OpenInventory>, Inventory> createBukkitEntity() {
+    org.bukkit.inventory.Inventory bukkitInventory;
+    if (viewOnly) {
+      bukkitInventory = new OpenDummyPlayerInventory(container);
+    } else if (ownContainer) {
+      bukkitInventory = new OpenPlayerInventorySelf(container, offset);
+    } else {
+      bukkitInventory = container.getBukkitInventory();
+    }
+
+    return new CraftInventoryView<>(viewer.getBukkitEntity(), bukkitInventory, this) {
+      @Override
+      public org.bukkit.inventory.ItemStack getItem(int index) {
+        if (viewOnly || index < 0) {
+          return null;
+        }
+
+        Slot slot = slots.get(index);
+        return CraftItemStack.asCraftMirror(slot.hasItem() ? slot.getItem() : ItemStack.EMPTY);
+      }
+
+      @Override
+      public boolean isInTop(int rawSlot) {
+        return rawSlot < topSize;
+      }
+
+      @Override
+      public @Nullable Inventory getInventory(int rawSlot) {
+        if (viewOnly) {
+          return null;
+        }
+        if (rawSlot == InventoryView.OUTSIDE || rawSlot == -1) {
+          return null;
+        }
+        Preconditions.checkArgument(rawSlot >= 0 && rawSlot < topSize + offset + BOTTOM_INVENTORY_SIZE,
+            "Slot %s outside of inventory", rawSlot);
+        if (rawSlot > topSize) {
+          return getBottomInventory();
+        }
+        Slot slot = slots.get(rawSlot);
+        if (slot.isFake()) {
+          return null;
+        }
+        return getTopInventory();
+      }
+
+      @Override
+      public int convertSlot(int rawSlot) {
+        if (viewOnly) {
+          return InventoryView.OUTSIDE;
+        }
+        if (rawSlot < 0) {
+          return rawSlot;
+        }
+        if (rawSlot < topSize) {
+          Slot slot = slots.get(rawSlot);
+          if (slot.isFake()) {
+            return InventoryView.OUTSIDE;
+          }
+          return rawSlot;
+        }
+
+        int slot = rawSlot - topSize;
+
+        if (slot >= 27) {
+          slot -= 27;
+        } else {
+          slot += 9;
+        }
+
+        return slot;
+      }
+
+      @Override
+      public @NotNull InventoryType.SlotType getSlotType(int slot) {
+        if (viewOnly || slot < 0) {
+          return InventoryType.SlotType.OUTSIDE;
+        }
+        if (slot >= topSize) {
+          slot -= topSize;
+          if (slot >= 27) {
+            return InventoryType.SlotType.QUICKBAR;
+          }
+          return InventoryType.SlotType.CONTAINER;
+        }
+        return OpenInventoryMenu.this.container.getSlotType(offset + slot);
+      }
+
+      @Override
+      public int countSlots() {
+        return topSize + BOTTOM_INVENTORY_SIZE;
+      }
+    };
+  }
+
+  @Override
+  public @NotNull ItemStack quickMoveStack(@NotNull Player player, int index) {
+    if (viewOnly) {
+      return ItemStack.EMPTY;
+    }
+
+    // See ChestMenu and InventoryMenu
+    Slot slot = this.slots.get(index);
+
+    if (!slot.hasItem() || slot.isFake()) {
+      return ItemStack.EMPTY;
+    }
+
+    ItemStack itemStack = slot.getItem();
+    ItemStack originalStack = itemStack.copy();
+
+    if (index < topSize) {
+      // If we're moving top to bottom, do a normal transfer.
+      if (!this.moveItemStackTo(itemStack, topSize, this.slots.size(), true)) {
+        return ItemStack.EMPTY;
+      }
+    } else {
+      EquipmentSlot equipmentSlot = player.getEquipmentSlotForItem(itemStack);
+      boolean movedGear = switch (equipmentSlot) {
+        // If this is gear, try to move it to the correct slot first.
+        case OFFHAND, FEET, LEGS, CHEST, HEAD -> {
+          // Locate the correct slot in the contents following the main inventory.
+          for (int extra = container.getOwnerHandle().getInventory().items.size() - offset; extra < topSize; ++extra) {
+            Slot extraSlot = getSlot(extra);
+            if (extraSlot instanceof ContentEquipment.SlotEquipment equipSlot
+                && equipSlot.getEquipmentSlot() == equipmentSlot) {
+              // If we've found a matching slot, try to move to it.
+              // If this succeeds, even partially, we will not attempt to move to other slots.
+              // Otherwise, armor is already occupied, so we'll fall through to main inventory.
+              yield this.moveItemStackTo(itemStack, extra, extra + 1, false);
+            }
+          }
+          yield false;
+        }
+        // Non-gear gets no special treatment.
+        default -> false;
+      };
+
+      // If main inventory is not available, there's nowhere else to move.
+      if (offset != 0) {
+        if (!movedGear) {
+          return ItemStack.EMPTY;
+        }
+      } else {
+        // If we didn't move to a gear slot, try to move to a main inventory slot.
+        if (!movedGear && !this.moveItemStackTo(itemStack, 0, container.getOwnerHandle().getInventory().items.size(), true)) {
+          return ItemStack.EMPTY;
+        }
+      }
+    }
+
+    if (itemStack.isEmpty()) {
+      slot.setByPlayer(ItemStack.EMPTY);
+    } else {
+      slot.setChanged();
+    }
+
+    return originalStack;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/Content.java

@@ -0,0 +1,69 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * An interface defining behaviors for entries in a {@link Container}. Used to reduce duplicate content reordering.
+ */
+public interface Content {
+
+  /**
+   * Update internal holder.
+   *
+   * @param holder the new holder
+   */
+  void setHolder(@NotNull ServerPlayer holder);
+
+  /**
+   * Get the current item.
+   *
+   * @return the current item
+   */
+  ItemStack get();
+
+  /**
+   * Remove the current item.
+   *
+   * @return the current item
+   */
+  ItemStack remove();
+
+  /**
+   * Remove some of the current item.
+   *
+   * @return the current item
+   */
+  ItemStack removePartial(int amount);
+
+  /**
+   * Set the current item. If slot is currently not usable, will drop item instead.
+   *
+   * @param itemStack the item to set
+   */
+  void set(ItemStack itemStack);
+
+  /**
+   * Get a {@link Slot} for use in a {@link net.minecraft.world.inventory.AbstractContainerMenu ContainerMenu}. Will
+   * impose any specific restrictions to insertion or removal.
+   *
+   * @param container the backing container
+   * @param slot the slot of the backing container represented
+   * @param x clientside x dimension from top left of inventory, not used
+   * @param y clientside y dimension from top left of inventory, not used
+   * @return a menu slot
+   */
+  Slot asSlot(Container container, int slot, int x, int y);
+
+  /**
+   * Get a loose Bukkit translation of what this slot stores. For example, any slot that drops items at the owner rather
+   * than insert them will report itself as being {@link org.bukkit.event.inventory.InventoryType.SlotType#OUTSIDE}.
+   *
+   * @return the closes Bukkit slot type
+   */
+  org.bukkit.event.inventory.InventoryType.SlotType getSlotType();
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentCrafting.java

@@ -0,0 +1,132 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import com.lishid.openinv.internal.common.container.Placeholders;
+import com.lishid.openinv.internal.common.player.OpenPlayer;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+/**
+ * A slot in a survival crafting inventory. Unavailable when not online in a survival mode.
+ */
+public class ContentCrafting implements Content {
+
+  private final int index;
+  private ServerPlayer holder;
+  private List<ItemStack> items;
+
+  public ContentCrafting(@NotNull ServerPlayer holder, int index) {
+    setHolder(holder);
+    this.index = index;
+  }
+
+  private boolean isAvailable() {
+    return isAvailable(holder);
+  }
+
+  static boolean isAvailable(@NotNull ServerPlayer holder) {
+    // Player must be online and not in creative - since the creative client is (semi-)authoritative,
+    // it ignores changes without extra help, and will delete the item as a result.
+    // Spectator mode is technically possible but may cause the item to be dropped if the client opens an inventory.
+    return OpenPlayer.isConnected(holder.connection) && holder.gameMode.isSurvival();
+  }
+
+  @Override
+  public void setHolder(@NotNull ServerPlayer holder) {
+    this.holder = holder;
+    // Note: CraftingContainer#getItems is immutable! Be careful with updates.
+    this.items = holder.inventoryMenu.getCraftSlots().getContents();
+  }
+
+  @Override
+  public ItemStack get() {
+    return isAvailable() ? items.get(index) : ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    if (!this.isAvailable()) {
+      return ItemStack.EMPTY;
+    }
+    ItemStack removed = items.remove(index);
+    if (removed.isEmpty()) {
+      return ItemStack.EMPTY;
+    }
+    holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+    return removed;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    if (!this.isAvailable()) {
+      return ItemStack.EMPTY;
+    }
+    ItemStack removed = ContainerHelper.removeItem(items, index, amount);
+    if (removed.isEmpty()) {
+      return ItemStack.EMPTY;
+    }
+    holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+    return removed;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    if (isAvailable()) {
+      items.set(index, itemStack);
+      holder.inventoryMenu.slotsChanged(holder.inventoryMenu.getCraftSlots());
+    } else {
+      holder.drop(itemStack, false);
+    }
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotCrafting(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return isAvailable() ? InventoryType.SlotType.CRAFTING : InventoryType.SlotType.OUTSIDE;
+  }
+
+  public class SlotCrafting extends SlotPlaceholder {
+
+    private SlotCrafting(Container container, int index, int x, int y) {
+      super(container, index, x, y);
+    }
+
+    @Override
+    public ItemStack getOrDefault() {
+      return isAvailable() ? items.get(ContentCrafting.this.index) : Placeholders.survivalOnly(holder);
+    }
+
+    @Override
+    public boolean mayPickup(@NotNull Player player) {
+      return isAvailable();
+    }
+
+    @Override
+    public boolean mayPlace(@NotNull ItemStack itemStack) {
+      return isAvailable();
+    }
+
+    @Override
+    public boolean hasItem() {
+      return isAvailable() && super.hasItem();
+    }
+
+    @Override
+    public boolean isFake() {
+      return !isAvailable();
+    }
+
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentCraftingResult.java

@@ -0,0 +1,48 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import com.lishid.openinv.internal.common.container.Placeholders;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.InventoryMenu;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A slot allowing viewing of the crafting result.
+ *
+ * <p>Unmodifiable because I said so. Use your own crafting grid.</p>
+ */
+public class ContentCraftingResult extends ContentViewOnly {
+
+  public ContentCraftingResult(@NotNull ServerPlayer holder) {
+    super(holder);
+  }
+
+  @Override
+  public ItemStack get() {
+    InventoryMenu inventoryMenu = holder.inventoryMenu;
+    return inventoryMenu.getResultSlot().getItem();
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotViewOnly(container, slot, x, y) {
+      @Override
+      public ItemStack getOrDefault() {
+        if (!ContentCrafting.isAvailable(holder)) {
+          return Placeholders.survivalOnly(holder);
+        }
+        InventoryMenu inventoryMenu = holder.inventoryMenu;
+        return inventoryMenu.getResultSlot().getItem();
+      }
+    };
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return InventoryType.SlotType.RESULT;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentCursor.java

@@ -0,0 +1,118 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import com.lishid.openinv.internal.common.container.Placeholders;
+import com.lishid.openinv.internal.common.player.OpenPlayer;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A slot wrapping the active menu's cursor. Unavailable when not online in a survival mode.
+ */
+public class ContentCursor implements Content {
+
+  private @NotNull ServerPlayer holder;
+
+  public ContentCursor(@NotNull ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public void setHolder(@NotNull ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public ItemStack get() {
+    return isAvailable() ? holder.containerMenu.getCarried() : ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    ItemStack carried = holder.containerMenu.getCarried();
+    holder.containerMenu.setCarried(ItemStack.EMPTY);
+    return carried;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    ItemStack carried = holder.containerMenu.getCarried();
+    if (!carried.isEmpty() && carried.getCount() >= amount) {
+      ItemStack value = carried.split(amount);
+      if (carried.isEmpty()) {
+        holder.containerMenu.setCarried(ItemStack.EMPTY);
+      }
+      return value;
+    }
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    if (isAvailable()) {
+      holder.containerMenu.setCarried(itemStack);
+    } else {
+      holder.drop(itemStack, false);
+    }
+  }
+
+  private boolean isAvailable() {
+    // Player must be online and not in creative - since the creative client is (semi-)authoritative,
+    // it ignores changes without extra help, and will delete the item as a result.
+    // Spectator mode is technically possible but may cause the item to be dropped if the client opens an inventory.
+    return OpenPlayer.isConnected(holder.connection) && holder.gameMode.isSurvival();
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotCursor(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    // As close as possible to "not real"
+    return InventoryType.SlotType.OUTSIDE;
+  }
+
+  public class SlotCursor extends SlotPlaceholder {
+
+    private SlotCursor(Container container, int index, int x, int y) {
+      super(container, index, x, y);
+    }
+
+    @Override
+    public ItemStack getOrDefault() {
+      if (!isAvailable()) {
+        return Placeholders.survivalOnly(holder);
+      }
+      ItemStack carried = holder.containerMenu.getCarried();
+      return carried.isEmpty() ? Placeholders.cursor : carried;
+    }
+
+    @Override
+    public boolean mayPickup(@NotNull Player player) {
+      return isAvailable();
+    }
+
+    @Override
+    public boolean mayPlace(@NotNull ItemStack itemStack) {
+      return isAvailable();
+    }
+
+    @Override
+    public boolean hasItem() {
+      return isAvailable() && super.hasItem();
+    }
+
+    @Override
+    public boolean isFake() {
+      return true;
+    }
+
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentDrop.java

@@ -0,0 +1,89 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import com.lishid.openinv.internal.common.container.Placeholders;
+import com.lishid.openinv.internal.common.player.OpenPlayer;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A fake slot used to drop items. Unavailable offline.
+ */
+public class ContentDrop implements Content {
+
+  private ServerPlayer holder;
+
+  public ContentDrop(@NotNull ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public void setHolder(@NotNull ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public ItemStack get() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    holder.drop(itemStack, true);
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotDrop(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    // Behaves like dropping an item outside the screen, just by the target player.
+    return InventoryType.SlotType.OUTSIDE;
+  }
+
+  public class SlotDrop extends SlotPlaceholder {
+
+    private SlotDrop(Container container, int index, int x, int y) {
+      super(container, index, x, y);
+    }
+
+    @Override
+    public ItemStack getOrDefault() {
+      return OpenPlayer.isConnected(holder.connection)
+          ? Placeholders.drop
+          : Placeholders.blockedOffline;
+    }
+
+    @Override
+    public boolean mayPlace(@NotNull ItemStack itemStack) {
+      return OpenPlayer.isConnected(holder.connection);
+    }
+
+    @Override
+    public boolean hasItem() {
+      return false;
+    }
+
+    @Override
+    public boolean isFake() {
+      return true;
+    }
+
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentEquipment.java

@@ -0,0 +1,78 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import com.lishid.openinv.internal.common.container.Placeholders;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A slot for equipment that displays placeholders if empty.
+ */
+public class ContentEquipment extends ContentList {
+
+  private final ItemStack placeholder;
+  private final EquipmentSlot equipmentSlot;
+
+  public ContentEquipment(ServerPlayer holder, int index, EquipmentSlot equipmentSlot) {
+    super(holder, index, InventoryType.SlotType.ARMOR);
+    placeholder = switch (equipmentSlot) {
+      case HEAD -> Placeholders.emptyHelmet;
+      case CHEST -> Placeholders.emptyChestplate;
+      case LEGS -> Placeholders.emptyLeggings;
+      case FEET -> Placeholders.emptyBoots;
+      default -> Placeholders.emptyOffHand;
+    };
+    this.equipmentSlot = equipmentSlot;
+  }
+
+  @Override
+  public void setHolder(@NotNull ServerPlayer holder) {
+    this.items = holder.getInventory().armor;
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotEquipment(container, slot, x, y);
+  }
+
+  public class SlotEquipment extends SlotPlaceholder {
+
+    private ServerPlayer viewer;
+
+    SlotEquipment(Container container, int index, int x, int y) {
+      super(container, index, x, y);
+    }
+
+    @Override
+    public ItemStack getOrDefault() {
+      ItemStack itemStack = getItem();
+      if (!itemStack.isEmpty()) {
+        return itemStack;
+      }
+      return placeholder;
+    }
+
+    public EquipmentSlot getEquipmentSlot() {
+      return equipmentSlot;
+    }
+
+    public void onlyEquipmentFor(ServerPlayer viewer) {
+      this.viewer = viewer;
+    }
+
+    @Override
+    public boolean mayPlace(@NotNull ItemStack itemStack) {
+      if (viewer == null) {
+        return true;
+      }
+
+      return equipmentSlot == EquipmentSlot.OFFHAND || viewer.getEquipmentSlotForItem(itemStack) == equipmentSlot;
+    }
+
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentList.java

@@ -0,0 +1,58 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.ContainerHelper;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+
+import java.util.List;
+
+/**
+ * A normal slot backed by an item list.
+ */
+public abstract class ContentList implements Content {
+
+  private final int index;
+  private final InventoryType.SlotType slotType;
+  protected List<ItemStack> items;
+
+  public ContentList(ServerPlayer holder, int index, InventoryType.SlotType slotType) {
+    this.index = index;
+    this.slotType = slotType;
+    setHolder(holder);
+  }
+
+  @Override
+  public ItemStack get() {
+    return items.get(index);
+  }
+
+  @Override
+  public ItemStack remove() {
+    ItemStack removed = items.remove(index);
+    return removed == null || removed.isEmpty() ? ItemStack.EMPTY : removed;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    return ContainerHelper.removeItem(items, index, amount);
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    items.set(index, itemStack);
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new Slot(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return slotType;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentOffHand.java

@@ -0,0 +1,52 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import com.lishid.openinv.internal.common.player.OpenPlayer;
+import net.minecraft.network.protocol.game.ClientboundContainerSetSlotPacket;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.inventory.InventoryMenu;
+import net.minecraft.world.inventory.Slot;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A slot for equipment that updates held items if necessary.
+ */
+public class ContentOffHand extends ContentEquipment {
+
+  private ServerPlayer holder;
+
+  public ContentOffHand(ServerPlayer holder, int localIndex) {
+    super(holder, localIndex, EquipmentSlot.OFFHAND);
+  }
+
+  @Override
+  public void setHolder(@NotNull ServerPlayer holder) {
+    this.items = holder.getInventory().offhand;
+    this.holder = holder;
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return InventoryType.SlotType.QUICKBAR;
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotEquipment(container, slot, x, y) {
+      @Override
+      public void setChanged() {
+        if (OpenPlayer.isConnected(holder.connection) && holder.containerMenu != holder.inventoryMenu) {
+          holder.connection.send(
+              new ClientboundContainerSetSlotPacket(
+                  holder.inventoryMenu.containerId,
+                  holder.inventoryMenu.incrementStateId(),
+                  InventoryMenu.SHIELD_SLOT,
+                  holder.getOffhandItem()));
+        }
+      }
+    };
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/ContentViewOnly.java

@@ -0,0 +1,56 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.bukkit.event.inventory.InventoryType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A view-only slot that can't be interacted with.
+ */
+public class ContentViewOnly implements Content {
+
+  @NotNull ServerPlayer holder;
+
+  public ContentViewOnly(@NotNull ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public void setHolder(@NotNull ServerPlayer holder) {
+    this.holder = holder;
+  }
+
+  @Override
+  public ItemStack get() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack remove() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public ItemStack removePartial(int amount) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public void set(ItemStack itemStack) {
+    this.holder.drop(itemStack, false);
+  }
+
+  @Override
+  public Slot asSlot(Container container, int slot, int x, int y) {
+    return new SlotViewOnly(container, slot, x, y);
+  }
+
+  @Override
+  public InventoryType.SlotType getSlotType() {
+    return InventoryType.SlotType.OUTSIDE;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/SlotPlaceholder.java

@@ -0,0 +1,20 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+
+/**
+ * An implementation of a slot as used by a menu that may have fake placeholder items.
+ *
+ * <p>Used to prevent plugins (particularly sorting plugins) from adding placeholders to inventories.</p>
+ */
+public abstract class SlotPlaceholder extends Slot {
+
+  public SlotPlaceholder(Container container, int index, int x, int y) {
+    super(container, index, x, y);
+  }
+
+  public abstract ItemStack getOrDefault();
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/container/slot/SlotViewOnly.java

@@ -0,0 +1,151 @@
+package com.lishid.openinv.internal.common.container.slot;
+
+import com.lishid.openinv.internal.common.container.Placeholders;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Optional;
+
+/**
+ * A view-only {@link Slot}. "Blank" by default, but can wrap another slot to display its content.
+ */
+public class SlotViewOnly extends SlotPlaceholder {
+
+  public static @NotNull SlotViewOnly wrap(@NotNull Slot wrapped) {
+    SlotViewOnly wrapper;
+    if (wrapped instanceof SlotPlaceholder placeholder) {
+      wrapper = new SlotViewOnly(wrapped.container, wrapped.slot, wrapped.x, wrapped.y) {
+        @Override
+        public ItemStack getOrDefault() {
+          return placeholder.getOrDefault();
+        }
+      };
+    } else {
+      wrapper = new SlotViewOnly(wrapped.container, wrapped.slot, wrapped.x, wrapped.y) {
+        @Override
+        public ItemStack getOrDefault() {
+          return wrapped.getItem();
+        }
+      };
+    }
+    wrapper.index = wrapped.index;
+    return wrapper;
+  }
+
+  public SlotViewOnly(Container container, int index, int x, int y) {
+    super(container, index, x, y);
+  }
+
+  @Override
+  public ItemStack getOrDefault() {
+    return Placeholders.notSlot;
+  }
+
+  @Override
+  public void onQuickCraft(@NotNull ItemStack itemStack1, @NotNull ItemStack itemStack2) {
+  }
+
+  @Override
+  public void onTake(@NotNull Player player, @NotNull ItemStack itemStack) {
+  }
+
+  @Override
+  public boolean mayPlace(@NotNull ItemStack itemStack) {
+    return false;
+  }
+
+  @Override
+  public @NotNull ItemStack getItem() {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public boolean hasItem() {
+    return false;
+  }
+
+  @Override
+  public void setByPlayer(@NotNull ItemStack newStack) {
+  }
+
+  @Override
+  public void setByPlayer(@NotNull ItemStack newStack, @NotNull ItemStack oldStack) {
+  }
+
+  @Override
+  public void set(@NotNull ItemStack itemStack) {
+  }
+
+  @Override
+  public void setChanged() {
+  }
+
+  @Override
+  public int getMaxStackSize() {
+    return 0;
+  }
+
+  @Override
+  public int getMaxStackSize(@NotNull ItemStack itemStack) {
+    return 0;
+  }
+
+  @Override
+  public @NotNull ItemStack remove(int amount) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public boolean mayPickup(@NotNull Player player) {
+    return false;
+  }
+
+  @Override
+  public boolean isActive() {
+    return false;
+  }
+
+  @Override
+  public @NotNull Optional<ItemStack> tryRemove(int var0, int var1, @NotNull Player player) {
+    return Optional.empty();
+  }
+
+  @Override
+  public @NotNull ItemStack safeTake(int var0, int var1, @NotNull Player player) {
+    return ItemStack.EMPTY;
+  }
+
+  @Override
+  public @NotNull ItemStack safeInsert(@NotNull ItemStack itemStack) {
+    return itemStack;
+  }
+
+  @Override
+  public @NotNull ItemStack safeInsert(@NotNull ItemStack itemStack, int amount) {
+    return itemStack;
+  }
+
+  @Override
+  public boolean allowModification(@NotNull Player player) {
+    return false;
+  }
+
+  @Override
+  public int getContainerSlot() {
+    return this.slot;
+  }
+
+  @Override
+  public boolean isHighlightable() {
+    return false;
+  }
+
+  @Override
+  public boolean isFake() {
+    return true;
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/player/OpenPlayer.java

@@ -0,0 +1,183 @@
+package com.lishid.openinv.internal.common.player;
+
+import com.lishid.openinv.event.OpenEvents;
+import com.mojang.logging.LogUtils;
+import net.minecraft.Util;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtIo;
+import net.minecraft.nbt.NumericTag;
+import net.minecraft.nbt.Tag;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.server.network.ServerGamePacketListenerImpl;
+import net.minecraft.world.level.storage.PlayerDataStorage;
+import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.craftbukkit.entity.CraftPlayer;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Set;
+
+public class OpenPlayer extends CraftPlayer {
+
+  /**
+   * List of tags to always reset when saving.
+   *
+   * @see net.minecraft.world.entity.Entity#saveWithoutId(CompoundTag)
+   * @see net.minecraft.server.level.ServerPlayer#addAdditionalSaveData(CompoundTag)
+   * @see net.minecraft.world.entity.player.Player#addAdditionalSaveData(CompoundTag)
+   * @see net.minecraft.world.entity.LivingEntity#addAdditionalSaveData(CompoundTag)
+   */
+  private static final Set<String> RESET_TAGS = Set.of(
+      // Entity#saveWithoutId(CompoundTag)
+      "CustomName",
+      "CustomNameVisible",
+      "Silent",
+      "NoGravity",
+      "Glowing",
+      "TicksFrozen",
+      "HasVisualFire",
+      "Tags",
+      "Passengers",
+      // ServerPlayer#addAdditionalSaveData(CompoundTag)
+      // Intentional omissions to prevent mount loss: Attach, Entity, and RootVehicle
+      "warden_spawn_tracker",
+      "enteredNetherPosition",
+      "SpawnX",
+      "SpawnY",
+      "SpawnZ",
+      "SpawnForced",
+      "SpawnAngle",
+      "SpawnDimension",
+      "raid_omen_position",
+      "ender_pearls",
+      // Player#addAdditionalSaveData(CompoundTag)
+      "ShoulderEntityLeft",
+      "ShoulderEntityRight",
+      "LastDeathLocation",
+      "current_explosion_impact_pos",
+      // LivingEntity#addAdditionalSaveData(CompoundTag)
+      "active_effects",
+      "SleepingX",
+      "SleepingY",
+      "SleepingZ",
+      "Brain"
+  );
+
+  private final PlayerManager manager;
+
+  OpenPlayer(CraftServer server, ServerPlayer entity, PlayerManager manager) {
+    super(server, entity);
+    this.manager = manager;
+  }
+
+  @Override
+  public void loadData() {
+    manager.loadData(getHandle());
+  }
+
+  @Override
+  public void saveData() {
+    if (OpenEvents.saveCancelled(this)) {
+      return;
+    }
+
+    ServerPlayer player = this.getHandle();
+    // See net.minecraft.world.level.storage.PlayerDataStorage#save(EntityHuman)
+    try {
+      PlayerDataStorage worldNBTStorage = player.server.getPlayerList().playerIo;
+
+      CompoundTag oldData = isOnline() ? null : worldNBTStorage.load(player.getName().getString(), player.getStringUUID()).orElse(null);
+      CompoundTag playerData = getWritableTag(oldData);
+      playerData = player.saveWithoutId(playerData);
+      setExtraData(playerData);
+
+      if (oldData != null) {
+        // Revert certain special data values when offline.
+        revertSpecialValues(playerData, oldData);
+      }
+
+      Path playerDataDir = worldNBTStorage.getPlayerDir().toPath();
+      Path tempFile = Files.createTempFile(playerDataDir, player.getStringUUID() + "-", ".dat");
+      NbtIo.writeCompressed(playerData, tempFile);
+      Path dataFile = playerDataDir.resolve(player.getStringUUID() + ".dat");
+      Path backupFile = playerDataDir.resolve(player.getStringUUID() + ".dat_old");
+      Util.safeReplaceFile(dataFile, tempFile, backupFile);
+    } catch (Exception e) {
+      LogUtils.getLogger().warn("Failed to save player data for {}: {}", player.getScoreboardName(), e);
+    }
+  }
+
+  @Contract("null -> new")
+  private @NotNull CompoundTag getWritableTag(@Nullable CompoundTag oldData) {
+    if (oldData == null) {
+      return new CompoundTag();
+    }
+
+    // Copy old data. This is a deep clone, so operating on it should be safe.
+    oldData = oldData.copy();
+
+    // Remove vanilla/server data that is not written every time.
+    oldData.getAllKeys()
+        .removeIf(key -> RESET_TAGS.contains(key) || key.startsWith("Bukkit"));
+
+    return oldData;
+  }
+
+  private void revertSpecialValues(@NotNull CompoundTag newData, @NotNull CompoundTag oldData) {
+    // Revert automatic updates to play timestamps.
+    copyValue(oldData, newData, "bukkit", "lastPlayed", NumericTag.class);
+    copyValue(oldData, newData, "Paper", "LastSeen", NumericTag.class);
+    copyValue(oldData, newData, "Paper", "LastLogin", NumericTag.class);
+  }
+
+  private <T extends Tag> void copyValue(
+      @NotNull CompoundTag source,
+      @NotNull CompoundTag target,
+      @NotNull String container,
+      @NotNull String key,
+      @SuppressWarnings("SameParameterValue") @NotNull Class<T> tagType) {
+    CompoundTag oldContainer = getTag(source, container, CompoundTag.class);
+    CompoundTag newContainer = getTag(target, container, CompoundTag.class);
+
+    // New container being null means the server implementation doesn't store this data.
+    if (newContainer == null) {
+      return;
+    }
+
+    // If old tag exists, copy it to new location, removing otherwise.
+    setTag(newContainer, key, getTag(oldContainer, key, tagType));
+  }
+
+  private <T extends Tag> @Nullable T getTag(
+      @Nullable CompoundTag container,
+      @NotNull String key,
+      @NotNull Class<T> dataType) {
+    if (container == null) {
+      return null;
+    }
+    Tag value = container.get(key);
+    if (value == null || !dataType.isAssignableFrom(value.getClass())) {
+      return null;
+    }
+    return dataType.cast(value);
+  }
+
+  private <T extends Tag> void setTag(
+      @NotNull CompoundTag container,
+      @NotNull String key,
+      @Nullable T data) {
+    if (data == null) {
+      container.remove(key);
+    } else {
+      container.put(key, data);
+    }
+  }
+
+  public static boolean isConnected(@Nullable ServerGamePacketListenerImpl connection) {
+    return connection != null && !connection.isDisconnected();
+  }
+
+}

internal/common/src/main/java/com/lishid/openinv/internal/common/player/PlayerManager.java

@@ -0,0 +1,276 @@
+package com.lishid.openinv.internal.common.player;
+
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.common.container.OpenEnderChest;
+import com.lishid.openinv.internal.common.container.OpenInventory;
+import com.mojang.authlib.GameProfile;
+import com.mojang.serialization.Dynamic;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtOps;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.protocol.game.ClientboundOpenScreenPacket;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.level.ClientInformation;
+import net.minecraft.server.level.ParticleStatus;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.player.ChatVisiblity;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.dimension.DimensionType;
+import org.bukkit.Bukkit;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.Server;
+import org.bukkit.World;
+import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.entity.CraftPlayer;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Field;
+import java.util.UUID;
+import java.util.logging.Logger;
+
+public class PlayerManager implements com.lishid.openinv.internal.PlayerManager {
+
+  private static boolean paper;
+
+  static {
+    try {
+      Class.forName("io.papermc.paper.configuration.Configuration");
+      paper = true;
+    } catch (ClassNotFoundException ignored) {
+      paper = false;
+    }
+  }
+
+  private final @NotNull Logger logger;
+  private @Nullable Field bukkitEntity;
+
+  public PlayerManager(@NotNull Logger logger) {
+    this.logger = logger;
+    try {
+      bukkitEntity = Entity.class.getDeclaredField("bukkitEntity");
+    } catch (NoSuchFieldException e) {
+      logger.warning("Unable to obtain field to inject custom save process - certain player data may be lost when saving!");
+      logger.log(java.util.logging.Level.WARNING, e.getMessage(), e);
+      bukkitEntity = null;
+    }
+  }
+
+  public static @NotNull ServerPlayer getHandle(final Player player) {
+    if (player instanceof CraftPlayer) {
+      return ((CraftPlayer) player).getHandle();
+    }
+
+    Server server = player.getServer();
+    ServerPlayer nmsPlayer = null;
+
+    if (server instanceof CraftServer) {
+      nmsPlayer = ((CraftServer) server).getHandle().getPlayer(player.getUniqueId());
+    }
+
+    if (nmsPlayer == null) {
+      // Could use reflection to examine fields, but it's honestly not worth the bother.
+      throw new RuntimeException("Unable to fetch EntityPlayer from Player implementation " + player.getClass().getName());
+    }
+
+    return nmsPlayer;
+  }
+
+  @Override
+  public @Nullable Player loadPlayer(@NotNull final OfflinePlayer offline) {
+    MinecraftServer server = ((CraftServer) Bukkit.getServer()).getServer();
+    ServerLevel worldServer = server.getLevel(Level.OVERWORLD);
+
+    if (worldServer == null) {
+      return null;
+    }
+
+    // Create a new ServerPlayer.
+    ServerPlayer entity = createNewPlayer(server, worldServer, offline);
+
+    // Stop listening for advancement progression - if this is not cleaned up, loading causes a memory leak.
+    entity.getAdvancements().stopListening();
+
+    // Try to load the player's data.
+    if (loadData(entity)) {
+      // If data is loaded successfully, return the Bukkit entity.
+      return entity.getBukkitEntity();
+    }
+
+    return null;
+  }
+
+  private @NotNull ServerPlayer createNewPlayer(
+      @NotNull MinecraftServer server,
+      @NotNull ServerLevel worldServer,
+      @NotNull final OfflinePlayer offline) {
+    // See net.minecraft.server.players.PlayerList#canPlayerLogin(ServerLoginPacketListenerImpl, GameProfile)
+    // See net.minecraft.server.network.ServerLoginPacketListenerImpl#handleHello(ServerboundHelloPacket)
+    GameProfile profile = new GameProfile(offline.getUniqueId(),
+        offline.getName() != null ? offline.getName() : offline.getUniqueId().toString());
+
+    ClientInformation dummyInfo = new ClientInformation(
+        "en_us",
+        1, // Reduce distance just in case.
+        ChatVisiblity.HIDDEN, // Don't accept chat.
+        false,
+        ServerPlayer.DEFAULT_MODEL_CUSTOMIZATION,
+        ServerPlayer.DEFAULT_MAIN_HAND,
+        true,
+        false, // Don't list in player list (not that this player is in the list anyway).
+        ParticleStatus.MINIMAL
+    );
+
+    ServerPlayer entity = new ServerPlayer(server, worldServer, profile, dummyInfo);
+
+    try {
+      injectPlayer(entity);
+    } catch (IllegalAccessException e) {
+      logger.log(
+          java.util.logging.Level.WARNING,
+          e,
+          () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
+    }
+
+    return entity;
+  }
+
+  boolean loadData(@NotNull ServerPlayer player) {
+    // See CraftPlayer#loadData
+    CompoundTag loadedData = player.server.getPlayerList().playerIo.load(player).orElse(null);
+
+    if (loadedData == null) {
+      // Exceptions with loading are logged by Mojang.
+      return false;
+    }
+
+    // Read basic data into the player.
+    player.load(loadedData);
+    // Also read "extra" data.
+    player.readAdditionalSaveData(loadedData);
+    // Game type settings are also loaded separately.
+    player.loadGameTypes(loadedData);
+
+    if (paper) {
+      // Paper: world is not loaded by ServerPlayer#load(CompoundTag).
+      parseWorld(player, loadedData);
+    }
+
+    return true;
+  }
+
+  private void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
+    // See PlayerList#placeNewPlayer
+    World bukkitWorld;
+    if (loadedData.contains("WorldUUIDMost") && loadedData.contains("WorldUUIDLeast")) {
+      // Modern Bukkit world.
+      bukkitWorld = Bukkit.getServer().getWorld(new UUID(loadedData.getLong("WorldUUIDMost"), loadedData.getLong("WorldUUIDLeast")));
+    } else if (loadedData.contains("world", net.minecraft.nbt.Tag.TAG_STRING)) {
+      // Legacy Bukkit world.
+      bukkitWorld = Bukkit.getServer().getWorld(loadedData.getString("world"));
+    } else {
+      // Vanilla player data.
+      DimensionType.parseLegacy(new Dynamic<>(NbtOps.INSTANCE, loadedData.get("Dimension")))
+          .resultOrPartial(logger::warning)
+          .map(player.server::getLevel)
+          // If ServerLevel exists, set, otherwise move to spawn.
+          .ifPresentOrElse(player::setServerLevel, () -> spawnInDefaultWorld(player));
+      return;
+    }
+    if (bukkitWorld == null) {
+      spawnInDefaultWorld(player);
+      return;
+    }
+    player.setServerLevel(((CraftWorld) bukkitWorld).getHandle());
+  }
+
+  private void spawnInDefaultWorld(ServerPlayer player) {
+    ServerLevel level = player.server.getLevel(Level.OVERWORLD);
+    if (level != null) {
+      player.spawnIn(level);
+    } else {
+      logger.warning("Tried to load player with invalid world when no fallback was available!");
+    }
+  }
+
+  private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
+    if (bukkitEntity == null) {
+      return;
+    }
+
+    bukkitEntity.setAccessible(true);
+
+    bukkitEntity.set(player, new OpenPlayer(player.server.server, player, this));
+  }
+
+  @Override
+  public @NotNull Player inject(@NotNull Player player) {
+    try {
+      ServerPlayer nmsPlayer = getHandle(player);
+      if (nmsPlayer.getBukkitEntity() instanceof OpenPlayer openPlayer) {
+        return openPlayer;
+      }
+      injectPlayer(nmsPlayer);
+      return nmsPlayer.getBukkitEntity();
+    } catch (IllegalAccessException e) {
+      logger.log(
+          java.util.logging.Level.WARNING,
+          e,
+          () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
+      return player;
+    }
+  }
+
+  @Override
+  public @Nullable InventoryView openInventory(@NotNull Player bukkitPlayer, @NotNull ISpecialInventory inventory, boolean viewOnly) {
+    ServerPlayer player = getHandle(bukkitPlayer);
+
+    if (!OpenPlayer.isConnected(player.connection)) {
+      return null;
+    }
+
+    // See net.minecraft.server.level.ServerPlayer#openMenu(MenuProvider)
+    AbstractContainerMenu menu;
+    Component title;
+    if (inventory instanceof OpenInventory playerInv) {
+      menu = playerInv.createMenu(player, player.nextContainerCounter(), viewOnly);
+      title = playerInv.getTitle(player);
+    } else if (inventory instanceof OpenEnderChest enderChest) {
+      menu = enderChest.createMenu(player, player.nextContainerCounter(), viewOnly);
+      title = enderChest.getTitle();
+    } else {
+      return null;
+    }
+
+    // Should never happen, player is a ServerPlayer with an active connection.
+    if (menu == null) {
+      return null;
+    }
+
+    // Set up title. Title can only be set once for a menu, and is set during the open process.
+    // Further title changes are a hack where the client is sent a "new" inventory with the same ID,
+    // resulting in a title change but no other state modifications (like cursor position).
+    menu.setTitle(title);
+
+    menu = CraftEventFactory.callInventoryOpenEvent(player, menu, false);
+
+    // Menu is null if event is cancelled.
+    if (menu == null) {
+      return null;
+    }
+
+    player.containerMenu = menu;
+    player.connection.send(new ClientboundOpenScreenPacket(menu.containerId, menu.getType(), menu.getTitle()));
+    player.initMenu(menu);
+
+    return menu.getBukkitView();
+  }
+
+}

internal/spigot/build.gradle.kts

@@ -0,0 +1,47 @@
+plugins {
+  `remap-spigot`
+  `openinv-base`
+  alias(libs.plugins.shadow)
+}
+
+repositories {
+  mavenLocal()
+}
+
+configurations.all {
+  resolutionStrategy.capabilitiesResolution.withCapability("org.spigotmc:spigot-api") {
+    val spigot = candidates.firstOrNull {
+      it.id.let {
+        id -> id is ModuleComponentIdentifier && id.module == "spigot-api"
+      }
+    }
+    if (spigot != null) {
+      select(spigot)
+    }
+    because("module is written for Spigot servers")
+  }
+}
+
+dependencies {
+  compileOnly(libs.spigotapi)
+  compileOnly(variantOf(libs.spigot) { classifier("remapped-mojang") })
+
+  compileOnly(project(":openinvapi"))
+  compileOnly(project(":openinvcommon"))
+
+  // Reduce duplicate code by lightly remapping common adapter.
+  implementation(project(":openinvadaptercommon", configuration = "spigotRelocated"))
+}
+
+tasks.shadowJar {
+  relocate("com.lishid.openinv.internal.common", "com.lishid.openinv.internal.reobf")
+}
+
+// TODO this appears to be a deprecated way to do things
+//   may want to just move all helper methods here.
+tasks.register<Remap_spigot_gradle.RemapTask>("reobf") {
+  notCompatibleWithConfigurationCache("gradle is hard")
+  dependsOn(tasks.shadowJar)
+  inputs.files(tasks.shadowJar.get().outputs.files.files)
+  spigotVersion = libs.spigot.get().version.toString()
+}

internal/spigot/src/main/java/com/lishid/openinv/internal/reobf/container/AnySilentContainer.java

@@ -0,0 +1,194 @@
+package com.lishid.openinv.internal.reobf.container;
+
+import com.lishid.openinv.internal.AnySilentContainerBase;
+import com.lishid.openinv.internal.reobf.container.menu.OpenChestMenu;
+import com.lishid.openinv.internal.reobf.player.PlayerManager;
+import com.lishid.openinv.util.ReflectionHelper;
+import com.lishid.openinv.util.lang.LanguageManager;
+import net.minecraft.core.BlockPos;
+import net.minecraft.network.chat.Component;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.server.level.ServerPlayerGameMode;
+import net.minecraft.world.MenuProvider;
+import net.minecraft.world.SimpleMenuProvider;
+import net.minecraft.world.inventory.ChestMenu;
+import net.minecraft.world.inventory.MenuType;
+import net.minecraft.world.inventory.PlayerEnderChestContainer;
+import net.minecraft.world.level.GameType;
+import net.minecraft.world.level.block.BarrelBlock;
+import net.minecraft.world.level.block.Block;
+import net.minecraft.world.level.block.ChestBlock;
+import net.minecraft.world.level.block.ShulkerBoxBlock;
+import net.minecraft.world.level.block.TrappedChestBlock;
+import net.minecraft.world.level.block.entity.BlockEntity;
+import net.minecraft.world.level.block.entity.EnderChestBlockEntity;
+import net.minecraft.world.level.block.entity.RandomizableContainerBlockEntity;
+import net.minecraft.world.level.block.state.BlockState;
+import org.bukkit.GameMode;
+import org.bukkit.Material;
+import org.bukkit.Statistic;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Field;
+import java.util.logging.Logger;
+
+public class AnySilentContainer extends AnySilentContainerBase {
+
+  private final @NotNull Logger logger;
+  private final @NotNull LanguageManager lang;
+  private @Nullable Field serverPlayerGameModeGameType;
+
+  public AnySilentContainer(@NotNull Logger logger, @NotNull LanguageManager lang) {
+    this.logger = logger;
+    this.lang = lang;
+    try {
+      try {
+        this.serverPlayerGameModeGameType = ServerPlayerGameMode.class.getDeclaredField("b");
+        this.serverPlayerGameModeGameType.setAccessible(true);
+      } catch (NoSuchFieldException e) {
+        logger.warning("The mapping of ServerPlayerGameMode#gameModeForPlayer has changed!");
+        logger.warning("Please report this at https://github.com/Jikoo/OpenInv/issues");
+        logger.warning("Attempting to fall through using reflection. Please verify that SilentContainer does not fail.");
+        // N.B. gameModeForPlayer is (for now) declared before previousGameModeForPlayer so silent shouldn't break.
+        this.serverPlayerGameModeGameType = ReflectionHelper.grabFieldByType(ServerPlayerGameMode.class, GameType.class);
+      }
+    } catch (SecurityException e) {
+      logger.warning("Unable to directly write player game mode! SilentContainer will fail.");
+      logger.log(java.util.logging.Level.WARNING, "Error obtaining GameType field", e);
+    }
+  }
+
+  @Override
+  public boolean activateContainer(
+      @NotNull final Player bukkitPlayer,
+      final boolean silentchest,
+      @NotNull final org.bukkit.block.Block bukkitBlock) {
+
+    // Silent ender chest is API-only
+    if (silentchest && bukkitBlock.getType() == Material.ENDER_CHEST) {
+      bukkitPlayer.openInventory(bukkitPlayer.getEnderChest());
+      bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
+      return true;
+    }
+
+    ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
+
+    final net.minecraft.world.level.Level level = player.level();
+    final BlockPos blockPos = new BlockPos(bukkitBlock.getX(), bukkitBlock.getY(), bukkitBlock.getZ());
+    final BlockEntity blockEntity = level.getBlockEntity(blockPos);
+
+    if (blockEntity == null) {
+      return false;
+    }
+
+    if (blockEntity instanceof EnderChestBlockEntity enderChestTile) {
+      // Anychest ender chest. See net.minecraft.world.level.block.EnderChestBlock
+      PlayerEnderChestContainer enderChest = player.getEnderChestInventory();
+      enderChest.setActiveChest(enderChestTile);
+      player.openMenu(new SimpleMenuProvider((containerCounter, playerInventory, ignored) -> {
+        MenuType<?> containers = OpenChestMenu.getChestMenuType(enderChest.getContainerSize());
+        int rows = enderChest.getContainerSize() / 9;
+        return new ChestMenu(containers, containerCounter, playerInventory, enderChest, rows);
+      }, Component.translatable("container.enderchest")));
+      bukkitPlayer.incrementStatistic(Statistic.ENDERCHEST_OPENED);
+      return true;
+    }
+
+    if (!(blockEntity instanceof MenuProvider menuProvider)) {
+      return false;
+    }
+
+    BlockState blockState = level.getBlockState(blockPos);
+    Block block = blockState.getBlock();
+
+    if (block instanceof ChestBlock chestBlock) {
+
+      // boolean flag: do not check if chest is blocked
+      menuProvider = chestBlock.getMenuProvider(blockState, level, blockPos, true);
+
+      if (menuProvider == null) {
+        lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+        return false;
+      }
+
+      if (block instanceof TrappedChestBlock) {
+        bukkitPlayer.incrementStatistic(Statistic.TRAPPED_CHEST_TRIGGERED);
+      } else {
+        bukkitPlayer.incrementStatistic(Statistic.CHEST_OPENED);
+      }
+    }
+
+    if (block instanceof ShulkerBoxBlock) {
+      bukkitPlayer.incrementStatistic(Statistic.SHULKER_BOX_OPENED);
+    }
+
+    if (block instanceof BarrelBlock) {
+      bukkitPlayer.incrementStatistic(Statistic.OPEN_BARREL);
+    }
+
+    // AnyChest only - SilentChest not active, container unsupported, or unnecessary.
+    if (!silentchest || player.gameMode.getGameModeForPlayer() == GameType.SPECTATOR) {
+      player.openMenu(menuProvider);
+      return true;
+    }
+
+    // SilentChest requires access to setting players' game mode directly.
+    if (this.serverPlayerGameModeGameType == null) {
+      return false;
+    }
+
+    if (blockEntity instanceof RandomizableContainerBlockEntity lootable) {
+      if (lootable.lootTable != null) {
+        lang.sendSystemMessage(bukkitPlayer, "messages.error.lootNotGenerated");
+        return false;
+      }
+    }
+
+    GameType gameType = player.gameMode.getGameModeForPlayer();
+    this.forceGameType(player, GameType.SPECTATOR);
+    player.openMenu(menuProvider);
+    this.forceGameType(player, gameType);
+    return true;
+  }
+
+  @Override
+  public void deactivateContainer(@NotNull final Player bukkitPlayer) {
+    if (this.serverPlayerGameModeGameType == null || bukkitPlayer.getGameMode() == GameMode.SPECTATOR) {
+      return;
+    }
+
+    ServerPlayer player = PlayerManager.getHandle(bukkitPlayer);
+
+    // Force game mode change without informing plugins or players.
+    // Regular game mode set calls GameModeChangeEvent and is cancellable.
+    GameType gameType = player.gameMode.getGameModeForPlayer();
+    this.forceGameType(player, GameType.SPECTATOR);
+
+    // ServerPlayer#closeContainer cannot be called without entering an
+    // infinite loop because this method is called during inventory close.
+    // From ServerPlayer#closeContainer -> CraftEventFactory#handleInventoryCloseEvent
+    player.containerMenu.transferTo(player.inventoryMenu, player.getBukkitEntity());
+    // From ServerPlayer#closeContainer
+    player.doCloseContainer();
+    // Regular inventory close will handle the rest - packet sending, etc.
+
+    // Revert forced game mode.
+    this.forceGameType(player, gameType);
+  }
+
+  private void forceGameType(final ServerPlayer player, final GameType gameMode) {
+    if (this.serverPlayerGameModeGameType == null) {
+      // No need to warn repeatedly, error on startup and lack of function should be enough.
+      return;
+    }
+    try {
+      this.serverPlayerGameModeGameType.setAccessible(true);
+      this.serverPlayerGameModeGameType.set(player.gameMode, gameMode);
+    } catch (IllegalArgumentException | IllegalAccessException e) {
+      logger.log(java.util.logging.Level.WARNING, "Error bypassing GameModeChangeEvent", e);
+    }
+  }
+
+}

internal/spigot/src/main/java/com/lishid/openinv/internal/reobf/player/PlayerManager.java

@@ -0,0 +1,276 @@
+package com.lishid.openinv.internal.reobf.player;
+
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.reobf.container.OpenEnderChest;
+import com.lishid.openinv.internal.reobf.container.OpenInventory;
+import com.mojang.authlib.GameProfile;
+import com.mojang.serialization.Dynamic;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtOps;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.protocol.game.ClientboundOpenScreenPacket;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.level.ClientInformation;
+import net.minecraft.server.level.ParticleStatus;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.player.ChatVisiblity;
+import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.dimension.DimensionType;
+import org.bukkit.Bukkit;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.Server;
+import org.bukkit.World;
+import org.bukkit.craftbukkit.v1_21_R3.CraftServer;
+import org.bukkit.craftbukkit.v1_21_R3.CraftWorld;
+import org.bukkit.craftbukkit.v1_21_R3.entity.CraftPlayer;
+import org.bukkit.craftbukkit.v1_21_R3.event.CraftEventFactory;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Field;
+import java.util.UUID;
+import java.util.logging.Logger;
+
+public class PlayerManager implements com.lishid.openinv.internal.PlayerManager {
+
+  private static boolean paper;
+
+  static {
+    try {
+      Class.forName("io.papermc.paper.configuration.Configuration");
+      paper = true;
+    } catch (ClassNotFoundException ignored) {
+      paper = false;
+    }
+  }
+
+  private final @NotNull Logger logger;
+  private @Nullable Field bukkitEntity;
+
+  public PlayerManager(@NotNull Logger logger) {
+    this.logger = logger;
+    try {
+      bukkitEntity = Entity.class.getDeclaredField("bukkitEntity");
+    } catch (NoSuchFieldException e) {
+      logger.warning("Unable to obtain field to inject custom save process - certain player data may be lost when saving!");
+      logger.log(java.util.logging.Level.WARNING, e.getMessage(), e);
+      bukkitEntity = null;
+    }
+  }
+
+  public static @NotNull ServerPlayer getHandle(final Player player) {
+    if (player instanceof CraftPlayer) {
+      return ((CraftPlayer) player).getHandle();
+    }
+
+    Server server = player.getServer();
+    ServerPlayer nmsPlayer = null;
+
+    if (server instanceof CraftServer) {
+      nmsPlayer = ((CraftServer) server).getHandle().getPlayer(player.getUniqueId());
+    }
+
+    if (nmsPlayer == null) {
+      // Could use reflection to examine fields, but it's honestly not worth the bother.
+      throw new RuntimeException("Unable to fetch EntityPlayer from Player implementation " + player.getClass().getName());
+    }
+
+    return nmsPlayer;
+  }
+
+  @Override
+  public @Nullable Player loadPlayer(@NotNull final OfflinePlayer offline) {
+    MinecraftServer server = ((CraftServer) Bukkit.getServer()).getServer();
+    ServerLevel worldServer = server.getLevel(Level.OVERWORLD);
+
+    if (worldServer == null) {
+      return null;
+    }
+
+    // Create a new ServerPlayer.
+    ServerPlayer entity = createNewPlayer(server, worldServer, offline);
+
+    // Stop listening for advancement progression - if this is not cleaned up, loading causes a memory leak.
+    entity.getAdvancements().stopListening();
+
+    // Try to load the player's data.
+    if (loadData(entity)) {
+      // If data is loaded successfully, return the Bukkit entity.
+      return entity.getBukkitEntity();
+    }
+
+    return null;
+  }
+
+  private @NotNull ServerPlayer createNewPlayer(
+      @NotNull MinecraftServer server,
+      @NotNull ServerLevel worldServer,
+      @NotNull final OfflinePlayer offline) {
+    // See net.minecraft.server.players.PlayerList#canPlayerLogin(ServerLoginPacketListenerImpl, GameProfile)
+    // See net.minecraft.server.network.ServerLoginPacketListenerImpl#handleHello(ServerboundHelloPacket)
+    GameProfile profile = new GameProfile(offline.getUniqueId(),
+        offline.getName() != null ? offline.getName() : offline.getUniqueId().toString());
+
+    ClientInformation dummyInfo = new ClientInformation(
+        "en_us",
+        1, // Reduce distance just in case.
+        ChatVisiblity.HIDDEN, // Don't accept chat.
+        false,
+        ServerPlayer.DEFAULT_MODEL_CUSTOMIZATION,
+        ServerPlayer.DEFAULT_MAIN_HAND,
+        true,
+        false, // Don't list in player list (not that this player is in the list anyway).
+        ParticleStatus.MINIMAL
+    );
+
+    ServerPlayer entity = new ServerPlayer(server, worldServer, profile, dummyInfo);
+
+    try {
+      injectPlayer(entity);
+    } catch (IllegalAccessException e) {
+      logger.log(
+          java.util.logging.Level.WARNING,
+          e,
+          () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
+    }
+
+    return entity;
+  }
+
+  boolean loadData(@NotNull ServerPlayer player) {
+    // See CraftPlayer#loadData
+    CompoundTag loadedData = player.server.getPlayerList().playerIo.load(player).orElse(null);
+
+    if (loadedData == null) {
+      // Exceptions with loading are logged by Mojang.
+      return false;
+    }
+
+    // Read basic data into the player.
+    player.load(loadedData);
+    // Also read "extra" data.
+    player.readAdditionalSaveData(loadedData);
+    // Game type settings are also loaded separately.
+    player.loadGameTypes(loadedData);
+
+    if (paper) {
+      // Paper: world is not loaded by ServerPlayer#load(CompoundTag).
+      parseWorld(player, loadedData);
+    }
+
+    return true;
+  }
+
+  private void parseWorld(@NotNull ServerPlayer player, @NotNull CompoundTag loadedData) {
+    // See PlayerList#placeNewPlayer
+    World bukkitWorld;
+    if (loadedData.contains("WorldUUIDMost") && loadedData.contains("WorldUUIDLeast")) {
+      // Modern Bukkit world.
+      bukkitWorld = Bukkit.getServer().getWorld(new UUID(loadedData.getLong("WorldUUIDMost"), loadedData.getLong("WorldUUIDLeast")));
+    } else if (loadedData.contains("world", net.minecraft.nbt.Tag.TAG_STRING)) {
+      // Legacy Bukkit world.
+      bukkitWorld = Bukkit.getServer().getWorld(loadedData.getString("world"));
+    } else {
+      // Vanilla player data.
+      DimensionType.parseLegacy(new Dynamic<>(NbtOps.INSTANCE, loadedData.get("Dimension")))
+          .resultOrPartial(logger::warning)
+          .map(player.server::getLevel)
+          // If ServerLevel exists, set, otherwise move to spawn.
+          .ifPresentOrElse(player::setServerLevel, () -> spawnInDefaultWorld(player));
+      return;
+    }
+    if (bukkitWorld == null) {
+      spawnInDefaultWorld(player);
+      return;
+    }
+    player.setServerLevel(((CraftWorld) bukkitWorld).getHandle());
+  }
+
+  private void spawnInDefaultWorld(ServerPlayer player) {
+    ServerLevel level = player.server.getLevel(Level.OVERWORLD);
+    if (level != null) {
+      player.spawnIn(level);
+    } else {
+      logger.warning("Tried to load player with invalid world when no fallback was available!");
+    }
+  }
+
+  private void injectPlayer(ServerPlayer player) throws IllegalAccessException {
+    if (bukkitEntity == null) {
+      return;
+    }
+
+    bukkitEntity.setAccessible(true);
+
+    bukkitEntity.set(player, new OpenPlayer(player.server.server, player, this));
+  }
+
+  @Override
+  public @NotNull Player inject(@NotNull Player player) {
+    try {
+      ServerPlayer nmsPlayer = getHandle(player);
+      if (nmsPlayer.getBukkitEntity() instanceof OpenPlayer openPlayer) {
+        return openPlayer;
+      }
+      injectPlayer(nmsPlayer);
+      return nmsPlayer.getBukkitEntity();
+    } catch (IllegalAccessException e) {
+      logger.log(
+          java.util.logging.Level.WARNING,
+          e,
+          () -> "Unable to inject ServerPlayer, certain player data may be lost when saving!");
+      return player;
+    }
+  }
+
+  @Override
+  public @Nullable InventoryView openInventory(@NotNull Player bukkitPlayer, @NotNull ISpecialInventory inventory, boolean viewOnly) {
+    ServerPlayer player = getHandle(bukkitPlayer);
+
+    if (!OpenPlayer.isConnected(player.connection)) {
+      return null;
+    }
+
+    // See net.minecraft.server.level.ServerPlayer#openMenu(MenuProvider)
+    AbstractContainerMenu menu;
+    Component title;
+    if (inventory instanceof OpenInventory playerInv) {
+      menu = playerInv.createMenu(player, player.nextContainerCounter(), viewOnly);
+      title = playerInv.getTitle(player);
+    } else if (inventory instanceof OpenEnderChest enderChest) {
+      menu = enderChest.createMenu(player, player.nextContainerCounter(), viewOnly);
+      title = enderChest.getTitle();
+    } else {
+      return null;
+    }
+
+    // Should never happen, player is a ServerPlayer with an active connection.
+    if (menu == null) {
+      return null;
+    }
+
+    // Set up title. Title can only be set once for a menu, and is set during the open process.
+    // Further title changes are a hack where the client is sent a "new" inventory with the same ID,
+    // resulting in a title change but no other state modifications (like cursor position).
+    menu.setTitle(title);
+
+    menu = CraftEventFactory.callInventoryOpenEvent(player, menu, false);
+
+    // Menu is null if event is cancelled.
+    if (menu == null) {
+      return null;
+    }
+
+    player.containerMenu = menu;
+    player.connection.send(new ClientboundOpenScreenPacket(menu.containerId, menu.getType(), menu.getTitle()));
+    player.initMenu(menu);
+
+    return menu.getBukkitView();
+  }
+
+}

jitpack.yml

@@ -0,0 +1,6 @@
+before_install:
+  - sdk update
+  - sdk install java 21-tem
+  - sdk use java 21-tem
+install:
+  - ./gradlew :openinvapi:publishJitpackPublicationToMavenLocal

plugin/build.gradle.kts

@@ -0,0 +1,42 @@
+plugins {
+  `openinv-base`
+  alias(libs.plugins.shadow)
+}
+
+repositories {
+  maven("https://jitpack.io")
+}
+
+dependencies {
+  implementation(project(":openinvapi"))
+  implementation(project(":openinvcommon"))
+  implementation(project(":openinvadaptercommon"))
+  implementation(project(":openinvadapterspigot", configuration = "shadow"))
+  implementation(libs.planarwrappers)
+}
+
+tasks.processResources {
+  expand("version" to version)
+}
+
+tasks.jar {
+  manifest.attributes("paperweight-mappings-namespace" to "mojang")
+}
+
+tasks.shadowJar {
+  dependsOn(":openinvadapterspigot:reobf")
+  minimize {
+    exclude(":openinv**")
+  }
+}
+
+tasks.register<Copy>("distributePlugin") {
+  into(rootProject.layout.projectDirectory.dir("dist"))
+  from(tasks.shadowJar)
+  rename("openinvplugin.*\\.jar", "OpenInv.jar")
+}
+
+tasks.assemble {
+  dependsOn(tasks.shadowJar)
+  dependsOn(tasks.named("distributePlugin"))
+}

plugin/src/main/java/com/lishid/openinv/OpenInv.java

@@ -0,0 +1,303 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv;
+
+import com.lishid.openinv.command.ContainerSettingCommand;
+import com.lishid.openinv.command.OpenInvCommand;
+import com.lishid.openinv.command.SearchContainerCommand;
+import com.lishid.openinv.command.SearchEnchantCommand;
+import com.lishid.openinv.command.SearchInvCommand;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.listener.ContainerListener;
+import com.lishid.openinv.listener.ToggleListener;
+import com.lishid.openinv.util.AccessEqualMode;
+import com.lishid.openinv.util.InternalAccessor;
+import com.lishid.openinv.util.InventoryManager;
+import com.lishid.openinv.util.Permissions;
+import com.lishid.openinv.util.PlayerLoader;
+import com.lishid.openinv.util.config.Config;
+import com.lishid.openinv.util.config.ConfigUpdater;
+import com.lishid.openinv.util.lang.LangMigrator;
+import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import com.lishid.openinv.util.setting.PlayerToggles;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.PluginCommand;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
+import org.bukkit.plugin.PluginManager;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.nio.file.Path;
+import java.util.Locale;
+import java.util.UUID;
+import java.util.function.Consumer;
+
+/**
+ * The main class for OpenInv.
+ */
+public class OpenInv extends JavaPlugin implements IOpenInv {
+
+    private InternalAccessor accessor;
+    private Config config;
+    private InventoryManager inventoryManager;
+    private LanguageManager languageManager;
+    private PlayerLoader playerLoader;
+    private boolean isSpigot = false;
+
+    @Override
+    public void reloadConfig() {
+        super.reloadConfig();
+        config.reload(getConfig());
+        languageManager.reload();
+        if (accessor != null && accessor.isSupported()) {
+            accessor.reload(getConfig());
+        }
+    }
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (!isSpigot || !this.accessor.isSupported()) {
+            this.sendVersionError(sender::sendMessage);
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public void onDisable() {
+        inventoryManager.evictAll();
+    }
+
+    @Override
+    public void onEnable() {
+        // Save default configuration if not present.
+        this.saveDefaultConfig();
+
+        // Migrate locale files to a subfolder.
+        Path dataFolder = getDataFolder().toPath();
+        new LangMigrator(dataFolder, dataFolder.resolve("locale"), getLogger()).migrate();
+
+        // Set up configurable features. Note that #reloadConfig is called on the first call to #getConfig!
+        // Configuration values should not be accessed until after all of these have been set up.
+        config = new Config();
+        languageManager = new LanguageManager(this, "en");
+        accessor = new InternalAccessor(getLogger(), languageManager);
+
+        // Perform initial config load.
+        reloadConfig();
+
+        inventoryManager = new InventoryManager(this, config, accessor);
+        playerLoader = new PlayerLoader(this, config, inventoryManager, accessor, getLogger());
+
+        try {
+            Class.forName("org.bukkit.entity.Player$Spigot");
+            isSpigot = true;
+        } catch (ClassNotFoundException e) {
+            isSpigot = false;
+        }
+
+        // Version check
+        if (isSpigot && this.accessor.isSupported()) {
+            reloadConfig();
+
+            // Update existing configuration. May require internal access.
+            new ConfigUpdater(this).checkForUpdates();
+
+            // Register relevant event listeners.
+            registerEvents();
+
+            // Register commands to their executors.
+            registerCommands();
+
+        } else {
+            this.sendVersionError(this.getLogger()::warning);
+        }
+
+    }
+
+    private void registerEvents() {
+        PluginManager pluginManager = this.getServer().getPluginManager();
+        pluginManager.registerEvents(playerLoader, this);
+        pluginManager.registerEvents(inventoryManager, this);
+        pluginManager.registerEvents(new ContainerListener(accessor, languageManager), this);
+        pluginManager.registerEvents(new ToggleListener(), this);
+    }
+
+    private void registerCommands() {
+        this.setCommandExecutor(new OpenInvCommand(this, config, inventoryManager, languageManager, playerLoader), "openinv", "openender");
+        this.setCommandExecutor(new SearchContainerCommand(this, languageManager), "searchcontainer");
+        this.setCommandExecutor(new SearchInvCommand(languageManager), "searchinv", "searchender");
+        this.setCommandExecutor(new SearchEnchantCommand(languageManager), "searchenchant");
+
+        ContainerSettingCommand settingCommand = new ContainerSettingCommand(languageManager);
+        for (PlayerToggle toggle : PlayerToggles.get()) {
+            setCommandExecutor(settingCommand, toggle.getName().toLowerCase(Locale.ENGLISH));
+        }
+    }
+
+    private void setCommandExecutor(@NotNull CommandExecutor executor, String @NotNull ... commands) {
+        for (String commandName : commands) {
+            PluginCommand command = this.getCommand(commandName);
+            if (command != null) {
+                command.setExecutor(executor);
+            }
+        }
+    }
+
+    private void sendVersionError(@NotNull Consumer<String> messageMethod) {
+        if (!accessor.isSupported()) {
+            messageMethod.accept("Your server version (" + accessor.getVersion() + ") is not supported.");
+            messageMethod.accept("Please download the correct version of OpenInv here: " + accessor.getReleasesLink());
+        }
+        if (!isSpigot) {
+            messageMethod.accept("OpenInv requires that you use Spigot or a Spigot fork. Per the 1.14 update thread");
+            messageMethod.accept("(https://www.spigotmc.org/threads/369724/ \"A Note on CraftBukkit\"), if you are");
+            messageMethod.accept("encountering an inconsistency with vanilla that prevents you from using Spigot,");
+            messageMethod.accept("that is considered a Spigot bug and should be reported as such.");
+        }
+    }
+
+    @Override
+    public boolean isSupportedVersion() {
+        return this.accessor != null && this.accessor.isSupported();
+    }
+
+    @Override
+    public boolean disableSaving() {
+        return config.isSaveDisabled();
+    }
+
+    @Override
+    public boolean disableOfflineAccess() {
+        return config.isOfflineDisabled();
+    }
+
+    @Override
+    public boolean noArgsOpensSelf() {
+        return config.doesNoArgsOpenSelf();
+    }
+
+    @Override
+    public @NotNull IAnySilentContainer getAnySilentContainer() {
+        return this.accessor.getAnySilentContainer();
+    }
+
+    @Override
+    public boolean getAnyContainerStatus(@NotNull final OfflinePlayer offline) {
+        return PlayerToggles.any().is(offline.getUniqueId());
+    }
+
+    @Override
+    public void setAnyContainerStatus(@NotNull final OfflinePlayer offline, final boolean status) {
+        PlayerToggles.any().set(offline.getUniqueId(), status);
+    }
+
+    @Override
+    public boolean getSilentContainerStatus(@NotNull final OfflinePlayer offline) {
+        return PlayerToggles.silent().is(offline.getUniqueId());
+    }
+
+    @Override
+    public void setSilentContainerStatus(@NotNull final OfflinePlayer offline, final boolean status) {
+        PlayerToggles.silent().set(offline.getUniqueId(), status);
+    }
+
+    @Override
+    public @NotNull ISpecialEnderChest getSpecialEnderChest(@NotNull final Player player, final boolean online) {
+        return inventoryManager.getEnderChest(player);
+    }
+
+    @Override
+    public @NotNull ISpecialPlayerInventory getSpecialInventory(@NotNull final Player player, final boolean online) {
+        return inventoryManager.getInventory(player);
+    }
+
+    @Override
+    public @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory) {
+        Permissions edit = null;
+        HumanEntity target = inventory.getPlayer();
+        boolean ownContainer = player.equals(target);
+        if (inventory instanceof ISpecialPlayerInventory) {
+            edit = ownContainer ? Permissions.INVENTORY_EDIT_SELF : Permissions.INVENTORY_EDIT_OTHER;
+        } else if (inventory instanceof ISpecialEnderChest) {
+            edit = ownContainer ? Permissions.ENDERCHEST_EDIT_SELF : Permissions.ENDERCHEST_EDIT_OTHER;
+        }
+
+        boolean viewOnly = edit != null && !edit.hasPermission(player);
+
+        if (ownContainer || viewOnly && config.getAccessEqualMode() != AccessEqualMode.DENY) {
+            return this.accessor.openInventory(player, inventory, viewOnly);
+        }
+
+        for (int level = 4; level > 0; --level) {
+            String permission = "openinv.access.level." + level;
+            // If the target doesn't have this access level...
+            if (!target.hasPermission(permission)) {
+                // If the viewer does have the access level, all good.
+                if (player.hasPermission(permission)) {
+                    break;
+                }
+                // Otherwise check next access level.
+                continue;
+            }
+
+            // If the viewer doesn't have an equal access level or equal access is a denial, deny.
+            if (!player.hasPermission(permission) || config.getAccessEqualMode() == AccessEqualMode.DENY) {
+                return null;
+            }
+
+            // Since this is a tie, setting decides view state.
+            if (config.getAccessEqualMode() == AccessEqualMode.VIEW) {
+                viewOnly = true;
+            }
+            break;
+        }
+
+        return this.accessor.openInventory(player, inventory, viewOnly);
+    }
+
+    @Override
+    public boolean isPlayerLoaded(@NotNull UUID playerUuid) {
+        return inventoryManager.getLoadedPlayer(playerUuid) != null;
+    }
+
+    @Override
+    public @Nullable Player loadPlayer(@NotNull final OfflinePlayer offline) {
+        return playerLoader.load(offline);
+    }
+
+    @Override
+    public @Nullable OfflinePlayer matchPlayer(@NotNull String name) {
+        return playerLoader.match(name);
+    }
+
+    @Override
+    public void unload(@NotNull final OfflinePlayer offline) {
+        inventoryManager.unload(offline.getUniqueId());
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/command/ContainerSettingCommand.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.command;
+
+import com.lishid.openinv.event.OpenEvents;
+import com.lishid.openinv.util.setting.PlayerToggle;
+import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.setting.PlayerToggles;
+import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabExecutor;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.UUID;
+
+public class ContainerSettingCommand implements TabExecutor {
+
+    private final @NotNull LanguageManager lang;
+
+    public ContainerSettingCommand(@NotNull LanguageManager lang) {
+        this.lang = lang;
+    }
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (!(sender instanceof Player player)) {
+            lang.sendMessage(sender, "messages.error.consoleUnsupported");
+            return true;
+        }
+
+        PlayerToggle toggle = PlayerToggles.get(command.getName());
+
+        // Shouldn't be possible.
+        if (toggle == null) {
+            JavaPlugin.getProvidingPlugin(getClass()).getLogger().warning("Command /" + command.getName() + " registered with no corresponding toggle!");
+            return false;
+        }
+
+        UUID playerId = player.getUniqueId();
+
+        if (args.length > 0) {
+            args[0] = args[0].toLowerCase(Locale.ENGLISH);
+
+            if (args[0].equals("on")) {
+                set(toggle, playerId, true);
+            } else if (args[0].equals("off")) {
+                set(toggle, playerId, false);
+            } else if (!args[0].equals("check")) {
+                // Invalid argument, show usage.
+                return false;
+            }
+
+        } else {
+            set(toggle, playerId, !toggle.is(playerId));
+        }
+
+        String onOff = lang.getLocalizedMessage(player, toggle.is(playerId) ? "messages.info.on" : "messages.info.off");
+        if (onOff == null) {
+            onOff = String.valueOf(toggle.is(playerId));
+        }
+
+        lang.sendMessage(
+                sender,
+                "messages.info.settingState",
+                new Replacement("%setting%", toggle.getName()),
+                new Replacement("%state%", onOff));
+
+        return true;
+    }
+
+    private void set(@NotNull PlayerToggle toggle, @NotNull UUID uuid, boolean state) {
+        if (toggle.set(uuid, state)) {
+            OpenEvents.notifyPlayerToggle(toggle, uuid, state);
+        }
+    }
+
+    @Override
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (!command.testPermissionSilent(sender) || args.length != 1) {
+            return Collections.emptyList();
+        }
+
+        return TabCompleter.completeString(args[0], new String[] {"check", "on", "off"});
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/command/OpenInvCommand.java

@@ -0,0 +1,249 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.command;
+
+import com.lishid.openinv.OpenInv;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.util.AccessEqualMode;
+import com.lishid.openinv.util.InventoryManager;
+import com.lishid.openinv.util.Permissions;
+import com.lishid.openinv.util.PlayerLoader;
+import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.config.Config;
+import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.PluginCommand;
+import org.bukkit.command.TabExecutor;
+import org.bukkit.entity.Player;
+import org.bukkit.scheduler.BukkitRunnable;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.StringJoiner;
+import java.util.logging.Level;
+
+public class OpenInvCommand implements TabExecutor {
+
+    private final @NotNull OpenInv plugin;
+    private final @NotNull Config config;
+    private final @NotNull InventoryManager manager;
+    private final @NotNull LanguageManager lang;
+    private final @NotNull PlayerLoader playerLoader;
+    private final HashMap<Player, String> openInvHistory = new HashMap<>();
+    private final HashMap<Player, String> openEnderHistory = new HashMap<>();
+
+    public OpenInvCommand(
+        @NotNull OpenInv plugin,
+        @NotNull Config config,
+        @NotNull InventoryManager manager,
+        @NotNull LanguageManager lang,
+        @NotNull PlayerLoader playerLoader) {
+        this.plugin = plugin;
+        this.config = config;
+        this.manager = manager;
+        this.lang = lang;
+        this.playerLoader = playerLoader;
+    }
+
+    @Override
+    public boolean onCommand(@NotNull final CommandSender sender, @NotNull final Command command, @NotNull final String label, @NotNull final String[] args) {
+        boolean openInv = command.getName().equals("openinv");
+
+        if (openInv && args.length > 0 && (args[0].equalsIgnoreCase("help") || args[0].equals("?"))) {
+            this.showHelp(sender);
+            return true;
+        }
+
+        if (!(sender instanceof Player player)) {
+            lang.sendMessage(sender, "messages.error.consoleUnsupported");
+            return true;
+        }
+
+        String noArgValue;
+        if (config.doesNoArgsOpenSelf()) {
+            noArgValue = player.getUniqueId().toString();
+        } else {
+            // History management
+            noArgValue = (openInv ? this.openInvHistory : this.openEnderHistory).get(player);
+
+            if (noArgValue == null || noArgValue.isEmpty()) {
+                noArgValue = player.getUniqueId().toString();
+                (openInv ? this.openInvHistory : this.openEnderHistory).put(player, noArgValue);
+            }
+        }
+
+        final String name;
+
+        if (args.length < 1) {
+            name = noArgValue;
+        } else {
+            name = args[0];
+        }
+
+        new BukkitRunnable() {
+            @Override
+            public void run() {
+                final OfflinePlayer offlinePlayer = playerLoader.match(name);
+
+                if (offlinePlayer == null || (!offlinePlayer.hasPlayedBefore() && !offlinePlayer.isOnline())) {
+                    lang.sendMessage(player, "messages.error.invalidPlayer");
+                    return;
+                }
+
+                new BukkitRunnable() {
+                    @Override
+                    public void run() {
+                        if (!player.isOnline()) {
+                            return;
+                        }
+                        OpenInvCommand.this.openInventory(player, offlinePlayer, openInv);
+                    }
+                }.runTask(OpenInvCommand.this.plugin);
+
+            }
+        }.runTaskAsynchronously(this.plugin);
+
+        return true;
+    }
+
+    private void showHelp(final CommandSender sender) {
+        // Get registered commands
+        for (String commandName : plugin.getDescription().getCommands().keySet()) {
+            PluginCommand command = plugin.getCommand(commandName);
+
+            // Ensure command is successfully registered and sender can use it
+            if (command == null  || !command.testPermissionSilent(sender)) {
+                continue;
+            }
+
+            // Send usage
+            sender.sendMessage(command.getUsage().replace("<command>", commandName));
+
+            List<String> aliases = command.getAliases();
+            if (!aliases.isEmpty()) {
+                // Assemble alias list
+                StringJoiner aliasJoiner = new StringJoiner(", ", "   (aliases: ", ")");
+                for (String alias : aliases) {
+                    aliasJoiner.add(alias);
+                }
+
+                // Send all aliases
+                sender.sendMessage(aliasJoiner.toString());
+            }
+
+        }
+    }
+
+    private void openInventory(final Player player, final OfflinePlayer target, boolean openinv) {
+        Player onlineTarget;
+        boolean online = target.isOnline();
+
+        if (!online) {
+            if (!config.isOfflineDisabled() && Permissions.ACCESS_OFFLINE.hasPermission(player)) {
+                // Try loading the player's data
+                onlineTarget = playerLoader.load(target);
+            } else {
+                lang.sendMessage(player, "messages.error.permissionPlayerOffline");
+                return;
+            }
+        } else {
+            if (Permissions.ACCESS_ONLINE.hasPermission(player)) {
+                onlineTarget = target.getPlayer();
+            } else {
+                lang.sendMessage(player, "messages.error.permissionPlayerOnline");
+                return;
+            }
+        }
+
+        if (onlineTarget == null) {
+            lang.sendMessage(player, "messages.error.invalidPlayer");
+            return;
+        }
+
+        // Permissions checks
+        if (onlineTarget.equals(player)) {
+            // Permission for opening own inventory.
+            if (!(openinv ? Permissions.INVENTORY_OPEN_SELF : Permissions.ENDERCHEST_OPEN_SELF).hasPermission(player)) {
+                lang.sendMessage(player, "messages.error.permissionOpenSelf");
+                return;
+
+            }
+        } else {
+            // Permission for opening others' inventories.
+            if (!(openinv ? Permissions.INVENTORY_OPEN_OTHER : Permissions.ENDERCHEST_OPEN_OTHER).hasPermission(player)) {
+                lang.sendMessage(player, "messages.error.permissionOpenOther");
+                return;
+            }
+
+            // Protected check
+            for (int level = 4; level > 0; --level) {
+                String permission = "openinv.access.level." + level;
+                if (onlineTarget.hasPermission(permission)
+                        && (!player.hasPermission(permission) || config.getAccessEqualMode() == AccessEqualMode.DENY)) {
+                    lang.sendMessage(
+                        player,
+                        "messages.error.permissionExempt",
+                        new Replacement("%target%", onlineTarget.getDisplayName()));
+                    return;
+                }
+            }
+
+            // Crossworld check
+            if (!Permissions.ACCESS_CROSSWORLD.hasPermission(player)
+                    && !onlineTarget.getWorld().equals(player.getWorld())) {
+                lang.sendMessage(
+                        player,
+                        "messages.error.permissionCrossWorld",
+                        new Replacement("%target%", onlineTarget.getDisplayName()));
+                return;
+            }
+        }
+
+        if (!config.doesNoArgsOpenSelf()) {
+            // Record the target
+            (openinv ? this.openInvHistory : this.openEnderHistory).put(player, target.getUniqueId().toString());
+        }
+
+        // Create the inventory
+        final ISpecialInventory inv;
+        try {
+            inv = openinv ? manager.getInventory(onlineTarget) : manager.getEnderChest(onlineTarget);
+        } catch (Exception e) {
+            lang.sendMessage(player, "messages.error.commandException");
+            plugin.getLogger().log(Level.WARNING, "Unable to create ISpecialInventory", e);
+            return;
+        }
+
+        // Open the inventory
+        plugin.openInventory(player, inv);
+    }
+
+    @Override
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (!command.testPermissionSilent(sender) || args.length != 1) {
+            return Collections.emptyList();
+        }
+
+        return TabCompleter.completeOnlinePlayer(sender, args[0]);
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/command/SearchContainerCommand.java

@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.command;
+
+import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.Chunk;
+import org.bukkit.Material;
+import org.bukkit.World;
+import org.bukkit.block.BlockState;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabExecutor;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryHolder;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Command for searching containers in a radius of chunks.
+ */
+public class SearchContainerCommand implements TabExecutor {
+
+    private final @NotNull Plugin plugin;
+    private final @NotNull LanguageManager lang;
+
+    public SearchContainerCommand(@NotNull Plugin plugin, @NotNull LanguageManager lang) {
+        this.plugin = plugin;
+        this.lang = lang;
+    }
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (!(sender instanceof Player senderPlayer)) {
+            lang.sendMessage(sender, "messages.error.consoleUnsupported");
+            return true;
+        }
+
+        if (args.length < 1) {
+            // Must supply material
+            return false;
+        }
+
+        Material material = Material.matchMaterial(args[0]);
+
+        if (material == null) {
+            lang.sendMessage(
+                    sender,
+                    "messages.error.invalidMaterial",
+                    new Replacement("%target%", args[0]));
+            return false;
+        }
+
+        int radius = 5;
+
+        if (args.length > 1) {
+            try {
+                radius = Integer.parseInt(args[1]);
+            } catch (NumberFormatException e) {
+                // Invalid radius supplied
+                return false;
+            }
+        }
+
+        // Clamp radius.
+        int configMax = plugin.getConfig().getInt("settings.command.searchcontainer.max-radius", 10);
+        radius = Math.max(0, Math.min(radius, configMax));
+
+        World world = senderPlayer.getWorld();
+        Chunk centerChunk = senderPlayer.getLocation().getChunk();
+        StringBuilder locations = new StringBuilder();
+
+        for (int dX = -radius; dX <= radius; ++dX) {
+            for (int dZ = -radius; dZ <= radius; ++dZ) {
+                if (!world.loadChunk(centerChunk.getX() + dX, centerChunk.getZ() + dZ, false)) {
+                    continue;
+                }
+                Chunk chunk = world.getChunkAt(centerChunk.getX() + dX, centerChunk.getZ() + dZ);
+                for (BlockState tileEntity : chunk.getTileEntities()) {
+                    if (!(tileEntity instanceof InventoryHolder holder)) {
+                        continue;
+                    }
+                    if (!holder.getInventory().contains(material)) {
+                        continue;
+                    }
+                    locations.append(holder.getInventory().getType().name().toLowerCase(Locale.ENGLISH)).append(" (")
+                            .append(tileEntity.getX()).append(',').append(tileEntity.getY()).append(',')
+                            .append(tileEntity.getZ()).append("), ");
+                }
+            }
+        }
+
+        // Matches found, delete trailing comma and space
+        if (!locations.isEmpty()) {
+            locations.delete(locations.length() - 2, locations.length());
+        } else {
+            lang.sendMessage(
+                    sender,
+                    "messages.info.container.noMatches",
+                    new Replacement("%target%", material.name()));
+            return true;
+        }
+
+        lang.sendMessage(
+                sender,
+                "messages.info.container.matches",
+                new Replacement("%target%", material.name()),
+                new Replacement("%detail%", locations.toString()));
+        return true;
+    }
+
+    @Override
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
+        if (args.length < 1 || args.length > 2 || !command.testPermissionSilent(sender)) {
+            return Collections.emptyList();
+        }
+
+        String argument = args[args.length - 1];
+        if (args.length == 1) {
+            return TabCompleter.completeEnum(argument, Material.class);
+        } else {
+            return TabCompleter.completeInteger(argument);
+        }
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/command/SearchEnchantCommand.java

@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.command;
+
+import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.NamespacedKey;
+import org.bukkit.Registry;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabExecutor;
+import org.bukkit.enchantments.Enchantment;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Command adding the ability to search online players' inventories for enchantments of a specific
+ * type at or above the level specified.
+ *
+ * @author Jikoo
+ */
+public class SearchEnchantCommand implements TabExecutor {
+
+    private final @NotNull LanguageManager lang;
+
+    public SearchEnchantCommand(@NotNull LanguageManager lang) {
+        this.lang = lang;
+    }
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (args.length == 0) {
+            return false;
+        }
+
+        Enchantment enchant = null;
+        int level = 0;
+
+        for (String argument : args) {
+            try {
+                level = Integer.parseInt(argument);
+                continue;
+            } catch (NumberFormatException ignored) {
+                // Not a level being specified.
+            }
+
+            argument = argument.toLowerCase(Locale.ENGLISH);
+            NamespacedKey key = NamespacedKey.fromString(argument);
+            if (key == null) {
+                continue;
+            }
+
+            Enchantment localEnchant = Registry.ENCHANTMENT.get(key);
+            if (localEnchant != null) {
+                enchant = localEnchant;
+            }
+        }
+
+        // Arguments not set correctly
+        if (level == 0 && enchant == null) {
+            return false;
+        }
+
+        StringBuilder players = new StringBuilder();
+        for (Player player : Bukkit.getServer().getOnlinePlayers()) {
+            boolean flagInventory = containsEnchantment(player.getInventory(), enchant, level);
+            boolean flagEnder = containsEnchantment(player.getEnderChest(), enchant, level);
+
+            // No matches, continue
+            if (!flagInventory && !flagEnder) {
+                continue;
+            }
+
+            // Matches, append details
+            players.append(player.getName()).append(" (");
+            if (flagInventory) {
+                players.append("inv");
+            }
+            if (flagEnder) {
+                if (flagInventory) {
+                    players.append(',');
+                }
+                players.append("ender");
+            }
+            players.append("), ");
+        }
+
+        if (!players.isEmpty()) {
+            // Matches found, delete trailing comma and space
+            players.delete(players.length() - 2, players.length());
+        } else {
+            lang.sendMessage(
+                    sender,
+                    "messages.info.player.noMatches",
+                    new Replacement("%target%", (enchant != null ? enchant.getKey().toString() : "") + " >= " + level));
+            return true;
+        }
+
+        lang.sendMessage(
+                sender,
+                "messages.info.player.matches",
+                new Replacement("%target%", (enchant != null ? enchant.getKey().toString() : "") + " >= " + level),
+                        new Replacement("%detail%", players.toString()));
+        return true;
+    }
+
+    private boolean containsEnchantment(Inventory inventory, @Nullable Enchantment enchant, int minLevel) {
+        for (ItemStack item : inventory.getContents()) {
+            if (item == null || item.getType() == Material.AIR) {
+                continue;
+            }
+            if (enchant != null) {
+                if (item.containsEnchantment(enchant) && item.getEnchantmentLevel(enchant) >= minLevel) {
+                    return true;
+                }
+            } else {
+                if (!item.hasItemMeta()) {
+                    continue;
+                }
+                ItemMeta meta = item.getItemMeta();
+                if (meta == null || !meta.hasEnchants()) {
+                    continue;
+                }
+                for (int enchLevel : meta.getEnchants().values()) {
+                    if (enchLevel >= minLevel) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (!command.testPermissionSilent(sender) || args.length < 1 || args.length > 2) {
+            return Collections.emptyList();
+        }
+
+        if (args.length == 1) {
+            return TabCompleter.completeObject(args[0], enchantment -> enchantment.getKey().toString(), Registry.ENCHANTMENT.stream().toArray(Enchantment[]::new));
+        } else {
+            return TabCompleter.completeInteger(args[1]);
+        }
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/command/SearchInvCommand.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.command;
+
+import com.lishid.openinv.util.TabCompleter;
+import com.lishid.openinv.util.lang.LanguageManager;
+import com.lishid.openinv.util.lang.Replacement;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabExecutor;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collections;
+import java.util.List;
+
+public class SearchInvCommand implements TabExecutor {
+
+    private final @NotNull LanguageManager lang;
+
+    public SearchInvCommand(@NotNull LanguageManager lang) {
+        this.lang = lang;
+    }
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+
+        Material material = null;
+
+        if (args.length >= 1) {
+            material = Material.matchMaterial(args[0]);
+        }
+
+        if (material == null) {
+            lang.sendMessage(
+                    sender,
+                    "messages.error.invalidMaterial",
+                    new Replacement("%target%", args.length > 0 ? args[0] : "null"));
+            return false;
+        }
+
+        int count = 1;
+
+        if (args.length >= 2) {
+            try {
+                count = Integer.parseInt(args[1]);
+            } catch (NumberFormatException ex) {
+                lang.sendMessage(
+                        sender,
+                        "messages.error.invalidNumber",
+                        new Replacement("%target%", args[1]));
+                return false;
+            }
+        }
+
+        StringBuilder players = new StringBuilder();
+        boolean searchInv = command.getName().equals("searchinv");
+        for (Player player : Bukkit.getServer().getOnlinePlayers()) {
+            Inventory inventory = searchInv ? player.getInventory() : player.getEnderChest();
+            int total = 0;
+            for (ItemStack itemStack : inventory.getContents()) {
+                if (itemStack != null && itemStack.getType() == material) {
+                    total += itemStack.getAmount();
+                    if (total >= count) {
+                        players.append(player.getName()).append(", ");
+                        break;
+                    }
+                }
+            }
+        }
+
+        // Matches found, delete trailing comma and space
+        if (!players.isEmpty()) {
+            players.delete(players.length() - 2, players.length());
+        } else {
+            lang.sendMessage(
+                    sender,
+                    "messages.info.player.noMatches",
+                    new Replacement("%target%", material.name()));
+            return true;
+        }
+
+        lang.sendMessage(
+                sender,
+                "messages.info.player.matches",
+                new Replacement("%target%", material.name()),
+                new Replacement("%detail%", players.toString()));
+        return true;
+    }
+
+    @Override
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+        if (args.length < 1 || args.length > 2 || !command.testPermissionSilent(sender)) {
+            return Collections.emptyList();
+        }
+
+        String argument = args[args.length - 1];
+        if (args.length == 1) {
+            return TabCompleter.completeEnum(argument, Material.class);
+        } else {
+            return TabCompleter.completeInteger(argument);
+        }
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/listener/ContainerListener.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.listener;
+
+import com.google.errorprone.annotations.Keep;
+import com.lishid.openinv.internal.ViewOnly;
+import com.lishid.openinv.util.InternalAccessor;
+import com.lishid.openinv.util.Permissions;
+import com.lishid.openinv.util.setting.PlayerToggles;
+import com.lishid.openinv.util.lang.LanguageManager;
+import org.bukkit.GameMode;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Event.Result;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.Action;
+import org.bukkit.event.inventory.InventoryClickEvent;
+import org.bukkit.event.inventory.InventoryCloseEvent;
+import org.bukkit.event.inventory.InventoryDragEvent;
+import org.bukkit.event.inventory.InventoryInteractEvent;
+import org.bukkit.event.player.PlayerInteractEvent;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryHolder;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.UUID;
+
+/**
+ * A listener managing AnyContainer, SilentContainer, and more.
+ */
+public class ContainerListener implements Listener {
+
+  private final @NotNull InternalAccessor accessor;
+  private final @NotNull LanguageManager lang;
+
+  public ContainerListener(@NotNull InternalAccessor accessor, @NotNull LanguageManager lang) {
+    this.accessor = accessor;
+    this.lang = lang;
+  }
+
+  @Keep
+  @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+  private void onPlayerInteract(@NotNull PlayerInteractEvent event) {
+    // Ignore events from other plugins.
+    if (!PlayerInteractEvent.class.equals(event.getClass())) {
+      return;
+    }
+
+    if (event.getAction() != Action.RIGHT_CLICK_BLOCK
+        || event.getPlayer().isSneaking()
+        || event.useInteractedBlock() == Result.DENY
+        || event.getClickedBlock() == null
+        || !accessor.getAnySilentContainer().isAnySilentContainer(event.getClickedBlock())) {
+      return;
+    }
+
+    Player player = event.getPlayer();
+    UUID playerId = player.getUniqueId();
+    boolean any = Permissions.CONTAINER_ANY.hasPermission(player) && PlayerToggles.any().is(playerId);
+    boolean needsAny = accessor.getAnySilentContainer().isAnyContainerNeeded(event.getClickedBlock());
+
+    if (!any && needsAny) {
+      return;
+    }
+
+    boolean silent = Permissions.CONTAINER_SILENT.hasPermission(player) && PlayerToggles.silent().is(playerId);
+
+    // If anycontainer or silentcontainer is active
+    if (any || silent) {
+      if (accessor.getAnySilentContainer().activateContainer(player, silent, event.getClickedBlock())) {
+        if (silent && needsAny) {
+          lang.sendSystemMessage(player, "messages.info.containerBlockedSilent");
+        } else if (needsAny) {
+          lang.sendSystemMessage(player, "messages.info.containerBlocked");
+        } else if (silent) {
+          lang.sendSystemMessage(player, "messages.info.containerSilent");
+        }
+      }
+      event.setCancelled(true);
+    }
+  }
+
+  @Keep
+  @EventHandler
+  private void onInventoryClose(@NotNull final InventoryCloseEvent event) {
+    if (!(event.getPlayer() instanceof Player player)) {
+      return;
+    }
+
+    InventoryHolder holder = event.getInventory().getHolder();
+    if (PlayerToggles.silent().is(player.getUniqueId())
+        && holder != null
+        && this.accessor.getAnySilentContainer().isAnySilentContainer(holder)) {
+      this.accessor.getAnySilentContainer().deactivateContainer(player);
+    }
+  }
+
+  @Keep
+  @EventHandler(priority = EventPriority.LOWEST)
+  private void onInventoryClick(@NotNull final InventoryClickEvent event) {
+    handleInventoryInteract(event);
+  }
+
+  @Keep
+  @EventHandler(priority = EventPriority.LOWEST)
+  private void onInventoryDrag(@NotNull final InventoryDragEvent event) {
+    handleInventoryInteract(event);
+  }
+
+  private void handleInventoryInteract(@NotNull final InventoryInteractEvent event) {
+    HumanEntity entity = event.getWhoClicked();
+
+    // Un-cancel spectator interactions.
+    if (entity.getGameMode() == GameMode.SPECTATOR && Permissions.SPECTATE_CLICK.hasPermission(entity)) {
+      event.setCancelled(false);
+    }
+
+    if (event.isCancelled()) {
+      return;
+    }
+
+    Inventory inventory = event.getView().getTopInventory();
+    if (inventory instanceof ViewOnly) {
+      event.setCancelled(true);
+    }
+  }
+
+}

plugin/src/main/java/com/lishid/openinv/listener/ToggleListener.java

@@ -0,0 +1,22 @@
+package com.lishid.openinv.listener;
+
+import com.google.errorprone.annotations.Keep;
+import com.lishid.openinv.util.setting.PlayerToggles;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.UUID;
+
+public class ToggleListener implements Listener {
+
+  @Keep
+  @EventHandler
+  private void onPlayerQuit(@NotNull PlayerQuitEvent event) {
+    UUID playerId = event.getPlayer().getUniqueId();
+    PlayerToggles.any().set(playerId, false);
+    PlayerToggles.silent().set(playerId, false);
+  }
+
+}

plugin/src/main/java/com/lishid/openinv/util/AccessEqualMode.java

@@ -0,0 +1,23 @@
+package com.lishid.openinv.util;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Locale;
+
+public enum AccessEqualMode {
+
+  DENY, ALLOW, VIEW;
+
+  public static @NotNull AccessEqualMode of(@Nullable String value) {
+    if (value == null) {
+      return VIEW;
+    }
+    return switch (value.toLowerCase(Locale.ENGLISH)) {
+      case "deny", "false" -> DENY;
+      case "allow", "true" -> ALLOW;
+      default -> VIEW;
+    };
+  }
+
+}

plugin/src/main/java/com/lishid/openinv/util/InternalAccessor.java

@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) 2011-2023 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util;
+
+import com.github.jikoo.planarwrappers.util.version.BukkitVersions;
+import com.github.jikoo.planarwrappers.util.version.Version;
+import com.lishid.openinv.internal.Accessor;
+import com.lishid.openinv.internal.IAnySilentContainer;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.internal.PlayerManager;
+import com.lishid.openinv.util.lang.LanguageManager;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.InventoryView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.logging.Logger;
+
+public class InternalAccessor {
+
+    private @Nullable Accessor internal;
+
+    public InternalAccessor(@NotNull Logger logger, @NotNull LanguageManager lang) {
+        boolean paper = false;
+        try {
+            Class.forName("io.papermc.paper.configuration.GlobalConfiguration");
+            paper = true;
+        } catch (ClassNotFoundException ignored) {
+            // Expect remapped server.
+        }
+
+        try {
+            Version maxSupported = Version.of(1, 21, 4);
+            // Placeholders currently mandate 1.21.4 minimum.
+            Version minSupported = Version.of(1, 21, 4);
+            if (!paper) {
+                if (BukkitVersions.MINECRAFT.equals(maxSupported)) {
+                    internal = new com.lishid.openinv.internal.reobf.InternalAccessor(logger, lang);
+                }
+            } else if (BukkitVersions.MINECRAFT.greaterThanOrEqual(minSupported)
+                    && BukkitVersions.MINECRAFT.lessThanOrEqual(maxSupported)) {
+                internal = new com.lishid.openinv.internal.common.InternalAccessor(logger, lang);
+            }
+            if (internal != null) {
+                InventoryAccess.setProvider(internal::get);
+            }
+        } catch (NoClassDefFoundError | Exception e) {
+            internal = null;
+            InventoryAccess.setProvider(null);
+        }
+    }
+
+    public String getReleasesLink() {
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 4, 4))) { // Good luck.
+            return "https://dev.bukkit.org/projects/openinv/files?&sort=datecreated";
+        }
+        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 8, 8))) { // 1.8.8
+            return "https://github.com/lishid/OpenInv/releases/tag/4.1.5";
+        }
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 13))) { // 1.4.4+ had versioned packages.
+            return "https://github.com/lishid/OpenInv/releases/tag/4.0.0 (OpenInv-legacy)";
+        }
+        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 13))) { // 1.13
+            return "https://github.com/lishid/OpenInv/releases/tag/4.0.0";
+        }
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 14))) { // 1.13.1, 1.13.2
+            return "https://github.com/lishid/OpenInv/releases/tag/4.0.7";
+        }
+        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 14))) { // 1.14 to 1.14.1 had no revision bump.
+            return "https://github.com/lishid/OpenInv/releases/tag/4.0.0";
+        }
+        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 14, 1))) { // 1.14.1 to 1.14.2 had no revision bump.
+            return "https://github.com/lishid/OpenInv/releases/tag/4.0.1";
+        }
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 15))) { // 1.14.2
+            return "https://github.com/lishid/OpenInv/releases/tag/4.1.1";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 15, 1))) { // 1.15, 1.15.1
+            return "https://github.com/lishid/OpenInv/releases/tag/4.1.5";
+        }
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 16))) { // 1.15.2
+            return "https://github.com/Jikoo/OpenInv/commit/502f661be39ee85d300851dd571f3da226f12345 (never released)";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 16, 1))) { // 1.16, 1.16.1
+            return "https://github.com/lishid/OpenInv/releases/tag/4.1.4";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 16, 3))) { // 1.16.2, 1.16.3
+            return "https://github.com/lishid/OpenInv/releases/tag/4.1.5";
+        }
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 17))) { // 1.16.4, 1.16.5
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.1.8";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 18, 1))) { // 1.17, 1.18, 1.18.1
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.1.10";
+        }
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 19))) { // 1.18.2
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.3.0";
+        }
+        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 19))) { // 1.19
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.2.0";
+        }
+        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 19, 1))) { // 1.19.1
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.2.2";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 19, 3))) { // 1.19.2, 1.19.3
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.3.0";
+        }
+        if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 20))) { // 1.19.4
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.4.3";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 20, 1))) { // 1.20, 1.20.1
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.4.1";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 20, 3))) { // 1.20.2, 1.20.3
+            return "https://github.com/Jikoo/OpenInv/releases/tag/4.4.3";
+        }
+        if (BukkitVersions.MINECRAFT.equals(Version.of(1, 20, 5))) { // 1.20.5
+            return "Unsupported; upgrade to 1.20.6: https://github.com/Jikoo/OpenInv/releases/tag/5.1.2";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 21))) { // 1.20.4, 1.20.6, 1.21
+            return "https://github.com/Jikoo/OpenInv/releases/tag/5.1.2";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 21, 2))) {
+            return "https://github.com/Jikoo/OpenInv/releases/tag/5.1.3";
+        }
+        if (BukkitVersions.MINECRAFT.lessThanOrEqual(Version.of(1, 21, 3))) {
+            return "https://github.com/Jikoo/OpenInv/releases/tag/5.1.6";
+        }
+        return "https://github.com/Jikoo/OpenInv/releases";
+    }
+
+    /**
+     * Reload internal features.
+     */
+    public void reload(ConfigurationSection config) {
+        if (internal != null) {
+            internal.reload(config);
+        }
+    }
+
+    /**
+     * Gets the server implementation version.
+     *
+     * @return the version
+     */
+    public @NotNull String getVersion() {
+        return BukkitVersions.MINECRAFT.toString();
+    }
+
+    /**
+     * Checks if the server implementation is supported.
+     *
+     * @return true if initialized for a supported server version
+     */
+    public boolean isSupported() {
+        return internal != null;
+    }
+
+    /**
+     * Get the instance of the IAnySilentContainer implementation for the current server version.
+     *
+     * @return the IAnySilentContainer
+     * @throws IllegalStateException if server version is unsupported
+     */
+    public @NotNull IAnySilentContainer getAnySilentContainer() {
+        if (internal == null) {
+            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
+        }
+        return internal.getAnySilentContainer();
+    }
+
+    public @Nullable InventoryView openInventory(@NotNull Player player, @NotNull ISpecialInventory inventory, boolean viewOnly) {
+        if (internal == null) {
+            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
+        }
+        return internal.getPlayerManager().openInventory(player, inventory, viewOnly);
+    }
+
+    /**
+     * Get the instance of the IPlayerDataManager implementation for the current server version.
+     *
+     * @return the IPlayerDataManager
+     * @throws IllegalStateException if server version is unsupported
+     */
+    @NotNull PlayerManager getPlayerDataManager() {
+        if (internal == null) {
+            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
+        }
+        return internal.getPlayerManager();
+    }
+
+    /**
+     * Creates an instance of the ISpecialEnderChest implementation for the given Player.
+     *
+     * @param player the Player
+     * @return the ISpecialEnderChest created
+     */
+    ISpecialEnderChest createEnderChest(final Player player) {
+        if (internal == null) {
+            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
+        }
+        return internal.createEnderChest(player);
+    }
+
+    /**
+     * Creates an instance of the ISpecialPlayerInventory implementation for the given Player.
+     *
+     * @param player the Player
+     * @return the ISpecialPlayerInventory created
+     */
+    ISpecialPlayerInventory createInventory(final Player player) {
+        if (internal == null) {
+            throw new IllegalStateException(String.format("Unsupported server version %s!", BukkitVersions.MINECRAFT));
+        }
+        return internal.createPlayerInventory(player);
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/util/InventoryManager.java

@@ -0,0 +1,280 @@
+package com.lishid.openinv.util;
+
+import com.github.jikoo.planarwrappers.util.version.BukkitVersions;
+import com.github.jikoo.planarwrappers.util.version.Version;
+import com.google.errorprone.annotations.Keep;
+import com.lishid.openinv.event.OpenEvents;
+import com.lishid.openinv.internal.ISpecialEnderChest;
+import com.lishid.openinv.internal.ISpecialInventory;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
+import com.lishid.openinv.util.config.Config;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.inventory.InventoryCloseEvent;
+import org.bukkit.event.inventory.InventoryOpenEvent;
+import org.bukkit.event.player.PlayerChangedWorldEvent;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Consumer;
+import java.util.logging.Level;
+import java.util.stream.Stream;
+
+/**
+ * A manager for special inventories. Delegates creation and tracks copies in use.
+ */
+public class InventoryManager implements Listener {
+
+  private final Map<UUID, ISpecialPlayerInventory> inventories = new ConcurrentHashMap<>();
+  private final Map<UUID, ISpecialEnderChest> enderChests = new ConcurrentHashMap<>();
+  private final Set<UUID> expectedCloses = new HashSet<>();
+  private final @NotNull Plugin plugin;
+  private final @NotNull Config config;
+  private final @NotNull InternalAccessor accessor;
+
+  public InventoryManager(@NotNull Plugin plugin, @NotNull Config config, @NotNull InternalAccessor accessor) {
+    this.plugin = plugin;
+    this.config = config;
+    this.accessor = accessor;
+  }
+
+  public void evictAll() {
+    Stream.concat(inventories.values().stream(), enderChests.values().stream())
+        .map(inventory -> {
+          // Rather than iterate twice, evict all viewers during remapping.
+          for (HumanEntity viewer : List.copyOf(inventory.getBukkitInventory().getViewers())) {
+            expectedCloses.add(viewer.getUniqueId());
+            viewer.closeInventory();
+          }
+          // If saving is prevented, return a null value for the player to save.
+          if (config.isSaveDisabled() || OpenEvents.saveCancelled(inventory)) {
+            return null;
+          }
+          if (inventory.getPlayer() instanceof Player player) {
+            return player;
+          }
+          return null;
+        })
+        .filter(Objects::nonNull)
+        .distinct()
+        .forEach(player -> {
+          if (!player.isOnline()) {
+            accessor.getPlayerDataManager().inject(player).saveData();
+          }
+        });
+    inventories.clear();
+    enderChests.clear();
+    expectedCloses.clear();
+  }
+
+  public @NotNull ISpecialPlayerInventory getInventory(@NotNull Player player) {
+    return inventories.computeIfAbsent(player.getUniqueId(), uuid -> accessor.createInventory(player));
+  }
+
+  public @NotNull ISpecialEnderChest getEnderChest(@NotNull Player player) {
+    return enderChests.computeIfAbsent(player.getUniqueId(), uuid -> accessor.createEnderChest(player));
+  }
+
+  public @Nullable Player getLoadedPlayer(@NotNull UUID uuid) {
+    ISpecialInventory inUse = inventories.get(uuid);
+    if (inUse != null) {
+      return (Player) inUse.getPlayer();
+    }
+    inUse = enderChests.get(uuid);
+    if (inUse != null) {
+      return (Player) inUse.getPlayer();
+    }
+    return null;
+  }
+
+  public void unload(@NotNull UUID uuid) {
+    inventories.computeIfPresent(uuid, this::remove);
+    enderChests.computeIfPresent(uuid, this::remove);
+  }
+
+  @Keep
+  @EventHandler(priority = EventPriority.LOWEST)
+  private void onPlayerJoin(@NotNull PlayerJoinEvent event) {
+    consumeLoaded(event.getPlayer().getUniqueId(), inventory -> {
+      inventory.setPlayerOnline(event.getPlayer());
+      checkViewerAccess(inventory, true);
+    });
+  }
+
+  @Keep
+  @EventHandler(priority = EventPriority.MONITOR)
+  private void onPlayerQuit(@NotNull PlayerQuitEvent event) {
+    consumeLoaded(event.getPlayer().getUniqueId(), inventory -> {
+      inventory.setPlayerOffline();
+      checkViewerAccess(inventory, false);
+    });
+  }
+
+  @Keep
+  @EventHandler
+  private void onWorldChanged(@NotNull PlayerChangedWorldEvent event) {
+    Player player = event.getPlayer();
+    consumeLoaded(player.getUniqueId(), inventory -> checkViewerAccess(inventory, player.isOnline()));
+  }
+
+  @Keep
+  @EventHandler
+  private void onInventoryClose(@NotNull InventoryCloseEvent event) {
+    ISpecialInventory inventory = InventoryAccess.getInventory(event.getInventory());
+
+    // If this is not an ISpecialInventory or the inventory was closed elsewhere internally, don't handle.
+    if (inventory == null || expectedCloses.remove(event.getPlayer().getUniqueId())) {
+      return;
+    }
+
+    // Fetch the active ISpecialInventory of this type.
+    Map<UUID, ? extends ISpecialInventory> map = inventory instanceof ISpecialPlayerInventory ? inventories : enderChests;
+    UUID key = inventory.getPlayer().getUniqueId();
+    ISpecialInventory loaded = map.get(key);
+
+    // If there is no loaded inventory, it has already been removed and saved.
+    if (loaded == null) {
+      return;
+    }
+
+    // This should only be possible if a plugin is going to extreme lengths to mess with our inventories.
+    if (loaded != inventory) {
+      // Immediately remove affected inventory, then dump all viewers. We don't want to risk duplication bugs.
+      map.remove(key);
+      remove(key, loaded);
+      remove(key, inventory);
+      // The loaded one is "correct" as far as we're concerned, so save that.
+      save(loaded);
+    }
+
+    // Schedule task to check in use status later this tick. Closing user is still in viewer list.
+    plugin.getServer().getScheduler().runTask(plugin, () -> {
+      if (loaded.isInUse()) {
+        return;
+      }
+
+      // Re-fetch from map to reduce odds of a duplicate save.
+      ISpecialInventory current = map.remove(key);
+
+      if (current != null) {
+        save(current);
+      }
+    });
+  }
+
+  @Keep
+  @EventHandler(priority = EventPriority.HIGHEST)
+  private void onInventoryOpen(@NotNull InventoryOpenEvent event) {
+    ISpecialInventory inventory = InventoryAccess.getInventory(event.getInventory());
+    if (inventory == null) {
+      return;
+    }
+
+    Map<UUID, ? extends ISpecialInventory> map = inventory instanceof ISpecialPlayerInventory ? inventories : enderChests;
+    UUID key = inventory.getPlayer().getUniqueId();
+    ISpecialInventory loaded = map.get(key);
+
+    if (!inventory.equals(loaded)) {
+      event.setCancelled(true);
+      plugin.getLogger().log(
+          Level.WARNING,
+          "Prevented a plugin from opening an untracked ISpecialInventory!",
+          new Throwable("Untracked ISpecialInventory"));
+    }
+  }
+
+  private <T extends ISpecialInventory> void checkViewerAccess(@NotNull T inventory, boolean online) {
+
+    Player owner = (Player) inventory.getPlayer();
+    Permissions connectedState = online ? Permissions.ACCESS_ONLINE : Permissions.ACCESS_OFFLINE;
+    boolean alwaysDenied = !online && config.isOfflineDisabled();
+
+    // Copy viewers so we don't modify the list we're iterating over when closing inventories.
+    List<HumanEntity> viewers = new ArrayList<>(inventory.getBukkitInventory().getViewers());
+    // Legacy: Owner is always a viewer of own inventory.
+    if (BukkitVersions.MINECRAFT.lessThan(Version.of(1, 21))) {
+      if (inventory instanceof ISpecialPlayerInventory) {
+        Inventory active = owner.getOpenInventory().getTopInventory();
+        if (!active.equals(inventory.getBukkitInventory())) {
+          viewers.remove(owner);
+        }
+      }
+    }
+
+    for (HumanEntity viewer : viewers) {
+      if (alwaysDenied
+          || !connectedState.hasPermission(viewer)
+          || (!Objects.equals(owner.getWorld(), viewer.getWorld()) && !Permissions.ACCESS_CROSSWORLD.hasPermission(viewer))) {
+        expectedCloses.add(viewer.getUniqueId());
+        viewer.closeInventory();
+      }
+    }
+  }
+
+  private void consumeLoaded(@NotNull UUID key, @NotNull Consumer<@NotNull ISpecialInventory> consumer) {
+    boolean saved = consumeLoaded(inventories, key, false, consumer);
+    consumeLoaded(enderChests, key, saved, consumer);
+  }
+
+  private <T extends ISpecialInventory> boolean consumeLoaded(
+      @NotNull Map<UUID, T> map,
+      @NotNull UUID key,
+      boolean saved,
+      @NotNull Consumer<@NotNull ISpecialInventory> consumer) {
+    T inventory = map.get(key);
+
+    if (inventory == null) {
+      return saved;
+    }
+
+    consumer.accept(inventory);
+    if (!inventory.isInUse()) {
+      map.remove(key);
+
+      if (!saved) {
+        save(inventory);
+        return true;
+      }
+    }
+
+    return saved;
+  }
+
+  private void save(@NotNull ISpecialInventory inventory) {
+    if (config.isSaveDisabled()) {
+      return;
+    }
+
+    Player player = (Player) inventory.getPlayer();
+
+    if (!player.isOnline() && !OpenEvents.saveCancelled(inventory)) {
+      accessor.getPlayerDataManager().inject(player).saveData();
+    }
+  }
+
+  @Contract("_, _ -> null")
+  private <T extends ISpecialInventory> @Nullable T remove(@NotNull UUID key, @NotNull T inventory) {
+    for (HumanEntity viewer : List.copyOf(inventory.getBukkitInventory().getViewers())) {
+      expectedCloses.add(viewer.getUniqueId());
+      viewer.closeInventory();
+    }
+    return null;
+  }
+
+}

plugin/src/main/java/com/lishid/openinv/util/PlayerLoader.java

@@ -0,0 +1,222 @@
+package com.lishid.openinv.util;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+import com.google.errorprone.annotations.Keep;
+import com.lishid.openinv.util.config.Config;
+import org.bukkit.Bukkit;
+import org.bukkit.OfflinePlayer;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.profile.PlayerProfile;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Iterator;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * A utility for looking up and loading players.
+ */
+public class PlayerLoader implements Listener {
+
+  private final @NotNull Plugin plugin;
+  private final @NotNull Config config;
+  private final @NotNull InventoryManager inventoryManager;
+  private final @NotNull InternalAccessor internalAccessor;
+  private final @NotNull Logger logger;
+  private final @NotNull Cache<String, PlayerProfile> lookupCache;
+
+  public PlayerLoader(
+      @NotNull Plugin plugin,
+      @NotNull Config config,
+      @NotNull InventoryManager inventoryManager,
+      @NotNull InternalAccessor internalAccessor,
+      @NotNull Logger logger) {
+    this.plugin = plugin;
+    this.config = config;
+    this.inventoryManager = inventoryManager;
+    this.internalAccessor = internalAccessor;
+    this.logger = logger;
+    this.lookupCache = CacheBuilder.newBuilder().maximumSize(20).build();
+  }
+
+  /**
+   * Load a {@link Player} from an {@link OfflinePlayer}. If the user has not played before or the default world for
+   * the server is not loaded, this will return {@code null}.
+   *
+   * @param offline the {@code OfflinePlayer} to load a {@code Player} for
+   * @return the loaded {@code Player}
+   * @throws IllegalStateException if the server version is unsupported
+   */
+  public @Nullable Player load(@NotNull OfflinePlayer offline) {
+    UUID key = offline.getUniqueId();
+
+    Player player = offline.getPlayer();
+    if (player != null) {
+      return player;
+    }
+
+    player = inventoryManager.getLoadedPlayer(key);
+    if (player != null) {
+      return player;
+    }
+
+    if (config.isOfflineDisabled() || !internalAccessor.isSupported()) {
+      return null;
+    }
+
+    if (Bukkit.isPrimaryThread()) {
+      return internalAccessor.getPlayerDataManager().loadPlayer(offline);
+    }
+
+    Future<Player> future = Bukkit.getScheduler().callSyncMethod(plugin,
+        () -> internalAccessor.getPlayerDataManager().loadPlayer(offline));
+
+    try {
+      player = future.get();
+    } catch (InterruptedException | ExecutionException e) {
+      logger.log(Level.WARNING, e.getMessage(), e);
+      return null;
+    }
+
+    return player;
+  }
+
+  public @Nullable OfflinePlayer match(@NotNull String name) {
+    // Warn if called on the main thread - if we resort to searching offline players, this may take several seconds.
+    if (Bukkit.getServer().isPrimaryThread()) {
+      logger.warning("Call to PlayerSearchCache#matchPlayer made on the main thread!");
+      logger.warning("This can cause the server to hang, potentially severely.");
+      logger.log(Level.WARNING, "Current stack trace", new Throwable("Current stack trace"));
+    }
+
+    OfflinePlayer player;
+
+    try {
+      UUID uuid = UUID.fromString(name);
+      player = Bukkit.getOfflinePlayer(uuid);
+      // Ensure player is an existing player.
+      if (player.hasPlayedBefore() || player.isOnline()) {
+        return player;
+      }
+      // Return null otherwise.
+      return null;
+    } catch (IllegalArgumentException ignored) {
+      // Not a UUID
+    }
+
+    // Exact online match first.
+    player = Bukkit.getServer().getPlayerExact(name);
+
+    if (player != null) {
+      return player;
+    }
+
+    // Cached offline match.
+    PlayerProfile cachedResult = lookupCache.getIfPresent(name);
+    if (cachedResult != null && cachedResult.getUniqueId() != null) {
+      player = Bukkit.getOfflinePlayer(cachedResult.getUniqueId());
+      // Ensure player is an existing player.
+      if (player.hasPlayedBefore() || player.isOnline()) {
+        return player;
+      }
+      // Return null otherwise.
+      return null;
+    }
+
+    // Exact offline match second - ensure offline access works when matchable users are online.
+    player = Bukkit.getServer().getOfflinePlayer(name);
+
+    if (player.hasPlayedBefore()) {
+      lookupCache.put(name, player.getPlayerProfile());
+      return player;
+    }
+
+    // Inexact online match.
+    player = Bukkit.getServer().getPlayer(name);
+
+    if (player != null) {
+      return player;
+    }
+
+    // Finally, inexact offline match.
+    float bestMatch = 0;
+    for (OfflinePlayer offline : Bukkit.getServer().getOfflinePlayers()) {
+      if (offline.getName() == null) {
+        // Loaded by UUID only, name has never been looked up.
+        continue;
+      }
+
+      float currentMatch = StringMetric.compareJaroWinkler(name, offline.getName());
+
+      if (currentMatch == 1.0F) {
+        return offline;
+      }
+
+      if (currentMatch > bestMatch) {
+        bestMatch = currentMatch;
+        player = offline;
+      }
+    }
+
+    if (player != null) {
+      // If a match was found, store it.
+      lookupCache.put(name, player.getPlayerProfile());
+      return player;
+    }
+
+    // No players have ever joined the server.
+    return null;
+  }
+
+  @Keep
+  @EventHandler
+  private void updateMatches(@NotNull PlayerJoinEvent event) {
+    // If player is not new, any cached values are valid.
+    if (event.getPlayer().hasPlayedBefore()) {
+      return;
+    }
+
+    // New player may have a name that already points to someone else in lookup cache.
+    String name = event.getPlayer().getName();
+    lookupCache.invalidate(name);
+
+    // If the cache is empty, nothing to do. Don't hit scheduler.
+    if (lookupCache.size() == 0) {
+      return;
+    }
+
+    plugin.getServer().getScheduler().runTaskLaterAsynchronously(plugin, () -> {
+      Iterator<Map.Entry<String, PlayerProfile>> iterator = lookupCache.asMap().entrySet().iterator();
+      while (iterator.hasNext()) {
+        Map.Entry<String, PlayerProfile> entry = iterator.next();
+        String oldMatch = entry.getValue().getName();
+
+        // Shouldn't be possible - all profiles should be complete.
+        if (oldMatch == null) {
+          iterator.remove();
+          continue;
+        }
+
+        String lookup = entry.getKey();
+        float oldMatchScore = StringMetric.compareJaroWinkler(lookup, oldMatch);
+        float newMatchScore = StringMetric.compareJaroWinkler(lookup, name);
+
+        // If new match exceeds old match, delete old match.
+        if (newMatchScore > oldMatchScore) {
+          iterator.remove();
+        }
+      }
+    }, 7L);
+  }
+
+}

plugin/src/main/java/com/lishid/openinv/util/StringMetric.java

@@ -0,0 +1,155 @@
+/*
+ * This file is an amalgamation of code from the Simmetrics authors.
+ * The originals may be found here:
+ * https://github.com/Simmetrics/simmetrics/blob/master/simmetrics-core/src/main/java/org/simmetrics/metrics/JaroWinkler.java
+ * https://github.com/Simmetrics/simmetrics/blob/master/simmetrics-core/src/main/java/org/simmetrics/metrics/Jaro.java
+ *
+ * Copyright (C) 2014 - 2016 Simmetrics Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.lishid.openinv.util;
+
+public class StringMetric {
+
+    public static float compareJaroWinkler(String a, String b) {
+        final float jaroScore = compareJaro(a, b);
+
+        if (jaroScore < (float) 0.7) {
+            return jaroScore;
+        }
+
+        String prefix = commonPrefix(a, b);
+        int prefixLength = Math.min(prefix.codePointCount(0, prefix.length()), 4);
+
+        return jaroScore + (prefixLength * (float) 0.1 * (1.0f - jaroScore));
+
+    }
+
+    private static float compareJaro(String a, String b) {
+        if (a.isEmpty() && b.isEmpty()) {
+            return 1.0f;
+        }
+
+        if (a.isEmpty() || b.isEmpty()) {
+            return 0.0f;
+        }
+
+        final int[] charsA = a.codePoints().toArray();
+        final int[] charsB = b.codePoints().toArray();
+
+        // Intentional integer division to round down.
+        final int halfLength = Math.max(0, Math.max(charsA.length, charsB.length) / 2 - 1);
+
+        final int[] commonA = getCommonCodePoints(charsA, charsB, halfLength);
+        final int[] commonB = getCommonCodePoints(charsB, charsA, halfLength);
+
+        // commonA and commonB will always contain the same multi-set of
+        // characters. Because getCommonCharacters has been optimized, commonA
+        // and commonB are -1-padded. So in this loop we count transposition
+        // and use commonCharacters to determine the length of the multi-set.
+        float transpositions = 0;
+        int commonCharacters = 0;
+        for (int length = commonA.length; commonCharacters < length
+                && commonA[commonCharacters] > -1; commonCharacters++) {
+            if (commonA[commonCharacters] != commonB[commonCharacters]) {
+                transpositions++;
+            }
+        }
+
+        if (commonCharacters == 0) {
+            return 0.0f;
+        }
+
+        float aCommonRatio = commonCharacters / (float) charsA.length;
+        float bCommonRatio = commonCharacters / (float) charsB.length;
+        float transpositionRatio = (commonCharacters - transpositions / 2.0f) / commonCharacters;
+
+        return (aCommonRatio + bCommonRatio + transpositionRatio) / 3.0f;
+    }
+
+    /*
+     * Returns an array of code points from a within b. A character in b is
+     * counted as common when it is within separation distance from the position
+     * in a.
+     */
+    private static int[] getCommonCodePoints(final int[] charsA, final int[] charsB, final int separation) {
+        final int[] common = new int[Math.min(charsA.length, charsB.length)];
+        final boolean[] matched = new boolean[charsB.length];
+
+        // Iterate of string a and find all characters that occur in b within
+        // the separation distance. Mark any matches found to avoid
+        // duplicate matchings.
+        int commonIndex = 0;
+        for (int i = 0, length = charsA.length; i < length; i++) {
+            final int character = charsA[i];
+            final int index = indexOf(character, charsB, i - separation, i
+                    + separation + 1, matched);
+            if (index > -1) {
+                common[commonIndex++] = character;
+                matched[index] = true;
+            }
+        }
+
+        if (commonIndex < common.length) {
+            common[commonIndex] = -1;
+        }
+
+        // Both invocations will yield the same multi-set terminated by -1, so
+        // they can be compared for transposition without making a copy.
+        return common;
+    }
+
+    /*
+     * Search for code point in buffer starting at fromIndex to toIndex - 1.
+     *
+     * Returns -1 when not found.
+     */
+    private static int indexOf(int character, int[] buffer, int fromIndex, int toIndex, boolean[] matched) {
+
+        // compare char with range of characters to either side
+        for (int j = Math.max(0, fromIndex), length = Math.min(toIndex, buffer.length); j < length; j++) {
+            // check if found
+            if (buffer[j] == character && !matched[j]) {
+                return j;
+            }
+        }
+
+        return -1;
+    }
+
+    private static String commonPrefix(CharSequence a, CharSequence b) {
+        int maxPrefixLength = Math.min(a.length(), b.length());
+
+        int p;
+
+        p = 0;
+        while (p < maxPrefixLength && a.charAt(p) == b.charAt(p)) {
+            ++p;
+        }
+
+        if (validSurrogatePairAt(a, p - 1) || validSurrogatePairAt(b, p - 1)) {
+            --p;
+        }
+
+        return a.subSequence(0, p).toString();
+    }
+
+    private static boolean validSurrogatePairAt(CharSequence string, int index) {
+        return index >= 0 && index <= string.length() - 2 && Character.isHighSurrogate(string.charAt(index)) && Character.isLowSurrogate(string.charAt(index + 1));
+    }
+
+    private StringMetric(){}
+
+}

plugin/src/main/java/com/lishid/openinv/util/TabCompleter.java

@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2011-2021 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util;
+
+import org.bukkit.Bukkit;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.bukkit.util.StringUtil;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.function.Function;
+
+/**
+ * Utility class for common tab completions.
+ */
+public final class TabCompleter {
+
+    /**
+     * Offer tab completions for whole numbers.
+     *
+     * @param argument the argument to complete
+     * @return integer options
+     */
+    public static List<String> completeInteger(String argument) {
+        // Ensure existing argument is actually a number
+        if (!argument.isEmpty()) {
+            try {
+                Integer.parseInt(argument);
+            } catch (NumberFormatException e) {
+                return Collections.emptyList();
+            }
+        }
+
+        List<String> completions = new ArrayList<>(10);
+        for (int i = 0; i < 10; ++i) {
+            completions.add(argument + i);
+        }
+
+        return completions;
+    }
+
+    /**
+     * Offer tab completions for a given Enum.
+     *
+     * @param argument the argument to complete
+     * @param enumClazz the Enum to complete for
+     * @return the matching Enum values
+     */
+    public static List<String> completeEnum(String argument, Class<? extends Enum<?>> enumClazz) {
+        argument = argument.toLowerCase(Locale.ENGLISH);
+        List<String> completions = new ArrayList<>();
+
+        for (Enum<?> enumConstant : enumClazz.getEnumConstants()) {
+            String name = enumConstant.name().toLowerCase(Locale.ENGLISH);
+            if (name.startsWith(argument)) {
+                completions.add(name);
+            }
+        }
+
+        return completions;
+    }
+
+    /**
+     * Offer tab completions for a given array of Strings.
+     *
+     * @param argument the argument to complete
+     * @param options the Strings which may be completed
+     * @return the matching Strings
+     */
+    public static List<String> completeString(String argument, String[] options) {
+        argument = argument.toLowerCase(Locale.ENGLISH);
+        List<String> completions = new ArrayList<>();
+
+        for (String option : options) {
+            if (option.startsWith(argument)) {
+                completions.add(option);
+            }
+        }
+
+        return completions;
+    }
+
+    /**
+     * Offer tab completions for visible online Players' names.
+     *
+     * @param sender the command's sender
+     * @param argument the argument to complete
+     * @return the matching Players' names
+     */
+    public static List<String> completeOnlinePlayer(CommandSender sender, String argument) {
+        List<String> completions = new ArrayList<>();
+        Player senderPlayer = sender instanceof Player ? (Player) sender : null;
+
+        for (Player player : Bukkit.getOnlinePlayers()) {
+            if (senderPlayer != null && !senderPlayer.canSee(player)) {
+                continue;
+            }
+
+            if (StringUtil.startsWithIgnoreCase(player.getName(), argument)) {
+                completions.add(player.getName());
+            }
+        }
+
+        return completions;
+    }
+
+    /**
+     * Offer tab completions for a given array of Objects.
+     *
+     * @param argument the argument to complete
+     * @param converter the Function for converting the Object into a comparable String
+     * @param options the Objects which may be completed
+     * @return the matching Strings
+     */
+    public static <T> List<String> completeObject(String argument, Function<T, String> converter, T[] options) {
+        argument = argument.toLowerCase(Locale.ENGLISH);
+        List<String> completions = new ArrayList<>();
+
+        for (T option : options) {
+            String optionString = converter.apply(option).toLowerCase(Locale.ENGLISH);
+            if (optionString.startsWith(argument)) {
+                completions.add(optionString);
+            }
+        }
+
+        return completions;
+    }
+
+    private TabCompleter() {
+        throw new IllegalStateException("Cannot create instance of utility class.");
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/util/config/Config.java

@@ -0,0 +1,43 @@
+package com.lishid.openinv.util.config;
+
+import com.lishid.openinv.util.AccessEqualMode;
+import org.bukkit.configuration.Configuration;
+import org.bukkit.configuration.MemoryConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class Config {
+
+  private @NotNull Configuration root;
+  private @Nullable AccessEqualMode accessEqualMode;
+
+  public Config() {
+    root = new MemoryConfiguration();
+  }
+
+  public void reload(@NotNull Configuration configuration) {
+    root = configuration;
+    accessEqualMode = null;
+  }
+
+  public boolean isSaveDisabled() {
+    return root.getBoolean("settings.disable-saving", false);
+  }
+
+  public boolean isOfflineDisabled() {
+    return root.getBoolean("settings.disable-offline-access", false);
+  }
+
+  public boolean doesNoArgsOpenSelf() {
+    return root.getBoolean("settings.command.open.no-args-opens-self", false);
+  }
+
+  public @NotNull AccessEqualMode getAccessEqualMode() {
+    if (accessEqualMode == null) {
+      accessEqualMode = AccessEqualMode.of(root.getString("settings.equal-access"));
+    }
+
+    return accessEqualMode;
+  }
+
+}

plugin/src/main/java/com/lishid/openinv/util/config/ConfigUpdater.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2011-2022 lishid. All rights reserved.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.lishid.openinv.util.config;
+
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.FileConfiguration;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.File;
+import java.io.IOException;
+
+public record ConfigUpdater(@NotNull Plugin plugin) {
+
+    public void checkForUpdates() {
+        final int version = plugin.getConfig().getInt("config-version", 1);
+        ConfigurationSection defaults = plugin.getConfig().getDefaults();
+        if (defaults == null || version >= defaults.getInt("config-version")) {
+            return;
+        }
+
+        plugin.getLogger().info("Configuration update found! Performing update...");
+
+        // Backup the old config file
+        try {
+            plugin.getConfig().save(new File(plugin.getDataFolder(), "config_old.yml"));
+            plugin.getLogger().info("Backed up config.yml to config_old.yml before updating.");
+        } catch (IOException e) {
+            plugin.getLogger().warning("Could not back up config.yml before updating!");
+        }
+
+        if (version < 2) {
+            updateConfig1To2();
+        }
+        if (version < 3) {
+            updateConfig2To3();
+        }
+        if (version < 4) {
+            updateConfig3To4();
+        }
+        if (version < 5) {
+            updateConfig4To5();
+        }
+        if (version < 6) {
+            updateConfig5To6();
+        }
+        if (version < 7) {
+            updateConfig6To7();
+        }
+        if (version < 8) {
+            updateConfig7To8();
+        }
+
+        plugin.saveConfig();
+        plugin.getLogger().info("Configuration update complete!");
+    }
+
+    private void updateConfig7To8() {
+        FileConfiguration config = plugin.getConfig();
+        config.set("settings.equal-access", "view");
+        config.set("config-version", 8);
+    }
+
+    private void updateConfig6To7() {
+        FileConfiguration config = plugin.getConfig();
+        config.set("toggles", null);
+        String consoleLocale = config.getString("settings.locale", "en");
+        if (consoleLocale.isBlank() || consoleLocale.equalsIgnoreCase("en_us")) {
+            consoleLocale = "en";
+        }
+        config.set("settings.console-locale", consoleLocale);
+        config.set("settings.locale", null);
+        config.set("config-version", 7);
+    }
+
+    private void updateConfig5To6() {
+        FileConfiguration config = plugin.getConfig();
+        config.set("settings.command.open.no-args-opens-self", false);
+        config.set("settings.command.searchcontainer.max-radius", 10);
+        config.set("config-version", 6);
+    }
+
+    private void updateConfig4To5() {
+        FileConfiguration config = plugin.getConfig();
+        config.set("settings.disable-offline-access", false);
+        config.set("config-version", 5);
+    }
+
+    private void updateConfig3To4() {
+        FileConfiguration config = plugin.getConfig();
+        config.set("notify", null);
+        config.set("config-version", 4);
+    }
+
+    private void updateConfig2To3() {
+        FileConfiguration config = plugin.getConfig();
+        config.set("items", null);
+        config.set("ItemOpenInv", null);
+        config.set("toggles", null);
+        config.set("settings.disable-saving", config.getBoolean("DisableSaving", false));
+        config.set("DisableSaving", null);
+        config.set("config-version", 3);
+    }
+
+    private void updateConfig1To2() {
+        FileConfiguration config = plugin.getConfig();
+        config.set("ItemOpenInvItemID", null);
+        config.set("NotifySilentChest", null);
+        config.set("NotifyAnyChest", null);
+        config.set("AnyChest", null);
+        config.set("SilentChest", null);
+        config.set("config-version", 2);
+    }
+
+}

plugin/src/main/java/com/lishid/openinv/util/lang/LangMigrator.java

@@ -0,0 +1,87 @@
+package com.lishid.openinv.util.lang;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.FileAlreadyExistsException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class LangMigrator {
+
+  private final @NotNull Path oldFolder;
+  private final @NotNull Path newFolder;
+  private final @NotNull Logger logger;
+
+  public LangMigrator(@NotNull Path oldFolder, @NotNull Path newFolder, @NotNull Logger logger) {
+    this.oldFolder = oldFolder;
+    this.newFolder = newFolder;
+    this.logger = logger;
+  }
+
+  public void migrate() {
+    if (!Files.exists(oldFolder.resolve("en_us.yml"))) {
+      // Probably already migrated.
+      return;
+    }
+
+    logger.info(() -> String.format("[LanguageManager] Migrating language files to %s", newFolder));
+
+    if (!Files.exists(newFolder)) {
+      try {
+        Files.createDirectories(newFolder);
+      } catch (IOException e) {
+        logger.log(Level.WARNING, "Unable to create language subdirectory!", e);
+      }
+    }
+
+    try (DirectoryStream<Path> files = Files.newDirectoryStream(oldFolder)) {
+      files.forEach(path -> {
+        if (path == null) {
+          return;
+        }
+
+        String fileName = path.getFileName().toString();
+
+        if (fileName.startsWith("config") || !fileName.endsWith(".yml")) {
+          return;
+        }
+
+        // Migrate certain files to be parent languages.
+        fileName = switch (fileName) {
+          case "en_us.yml" -> "en.yml";
+          case "de_de.yml" -> "de.yml";
+          case "es_es.yml" -> "es.yml";
+          case "pt_br.yml" -> "pt.yml";
+          default -> fileName;
+        };
+
+        try {
+          Files.copy(path, newFolder.resolve(fileName));
+          Files.delete(path);
+        } catch (FileAlreadyExistsException e1) {
+          // File already migrated?
+          try {
+            Files.copy(path, newFolder.resolve("old_" + fileName));
+            Files.delete(path);
+          } catch (IOException e2) {
+            // If it fails again, just re-throw.
+            throw new UncheckedIOException(e2);
+          }
+        } catch (IOException e) {
+          throw new UncheckedIOException(e);
+        }
+      });
+    } catch (UncheckedIOException e) {
+      logger.log(Level.WARNING, "Unable to migrate languages to subdirectory!", e.getCause());
+    } catch (IOException e) {
+      logger.log(Level.WARNING, "Unable to migrate languages to subdirectory!", e);
+    }
+
+  }
+
+}

plugin/src/main/resources/config.yml

@@ -0,0 +1,11 @@
+config-version: 8
+settings:
+  equal-access: allow
+  command:
+    open:
+      no-args-opens-self: false
+    searchcontainer:
+      max-radius: 10
+  disable-offline-access: false
+  disable-saving: false
+  console-locale: 'en'

plugin/src/main/resources/locale/de.yml

@@ -0,0 +1,30 @@
+messages:
+  error:
+    consoleUnsupported: 'Du kannst diesen Befehl nicht von der Konsole ausführen.'
+    lootNotGenerated: '&cBeute noch nicht erstellt! Bitte schalte &b/silentcontainer&c aus.'
+    invalidMaterial: '&cUngültiges Material: "%target%"'
+    invalidNumber: '&cUngültige Nummer: "%target%"'
+    invalidPlayer: '&cSpieler nicht gefunden.'
+    permissionOpenSelf: '&cDu darfst dein eigenes Inventar nicht öffnen.'
+    permissionEnderAll: '&cDu darfst die Endertruhen von anderen Spielern nicht öffnen.'
+    permissionExempt: '&c%target%''s Inventar ist geschützt.'
+    permissionCrossWorld: '&c%target% ist nicht in der selben Welt wie du.'
+    permissionPlayerOnline: '&cDu darfst keine Inventare von Spielern öffnen, die online sind.'
+    permissionPlayerOffline: '&cDu darfst keine Inventare von Spielern öffnen, die offline sind.'
+    commandException: '&cAn error occurred. Please check console for details.'
+  info:
+    containerBlocked: 'Du öffnest einen gesperrten Container.'
+    containerBlockedSilent: 'Du öffnest einen gesperrten Container lautlos.'
+    containerSilent: 'Du öffnest einen Container lautlos.'
+    settingState: '%setting%: %state%'
+    player:
+      noMatches: 'Keine Spieler mit %target% gefunden.'
+      matches: 'Spieler hält %target%: %detail%'
+    container:
+      noMatches: 'Keine Container mit %target% gefunden.'
+      matches: 'Container hat %target%: %detail%'
+    'on': 'an'
+    'off': 'aus'
+container:
+  player: '%player%''s Inventar'
+  enderchest: '%player%''s Endertruhe'

plugin/src/main/resources/locale/en.yml

@@ -0,0 +1,30 @@
+messages:
+  error:
+    consoleUnsupported: 'You cannot use this command from console.'
+    lootNotGenerated: '&cLoot not generated! Please disable &b/silentcontainer&c.'
+    invalidMaterial: '&cInvalid material: "%target%"'
+    invalidNumber: '&cInvalid number: "%target%"'
+    invalidPlayer: '&cPlayer not found!'
+    permissionOpenSelf: '&cYou''re not allowed to open your own inventory.'
+    permissionOpenOther: '&cYou''re not allowed to access others'' inventories.'
+    permissionExempt: '&c%target%''s inventory is protected.'
+    permissionCrossWorld: '&c%target% is not in your world.'
+    permissionPlayerOnline: '&cYou''re not allowed to open inventories of online players.'
+    permissionPlayerOffline: '&cYou''re not allowed to open inventories of offline players.'
+    commandException: '&cAn error occurred. Please check console for details.'
+  info:
+    containerBlocked: 'You are opening a blocked container.'
+    containerBlockedSilent: 'You are opening a blocked container silently.'
+    containerSilent: 'You are opening a container silently.'
+    settingState: '%setting%: %state%'
+    player:
+      noMatches: 'No players found with %target%.'
+      matches: 'Players holding %target%: %detail%'
+    container:
+      noMatches: 'No containers found with %target%.'
+      matches: 'Containers holding %target%: %detail%'
+    'on': 'on'
+    'off': 'off'
+container:
+  player: '%player%''s Inventory'
+  enderchest: '%player%''s Ender Chest'