Reintroduce GeyserDefineCommandsEvent and cleanup a few things

api/base/build.gradle.kts

@@ -1,4 +1,7 @@
 dependencies {
     api("org.geysermc.cumulus", "cumulus", Versions.cumulusVersion)
-    api("org.geysermc.event", "events", Versions.eventsVersion)
+    api("org.geysermc.event", "events", Versions.eventsVersion) {
+        exclude(group = "com.google.guava", module = "guava")
+        exclude(group = "org.lanternpowered", module = "lmbda")
+    }
 }

api/base/src/main/java/org/geysermc/api/Geyser.java

@@ -69,7 +69,7 @@ public class Geyser {
 
     /**
      * Registers the given api type. The api cannot be
-     * registered if {@link #registered()} is true as
+     * registered if {@link #isRegistered()} is true as
      * an api has already been specified.
      *
      * @param api the api
@@ -88,7 +88,7 @@ public class Geyser {
      *
      * @return if the api has been registered
      */
-    public static boolean registered() {
+    public static boolean isRegistered() {
         return api != null;
     }
 }

api/geyser/src/main/java/org/geysermc/geyser/api/GeyserApi.java

@@ -29,7 +29,6 @@ import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.geysermc.api.Geyser;
 import org.geysermc.api.GeyserApiBase;
-import org.geysermc.geyser.api.command.CommandManager;
 import org.geysermc.geyser.api.connection.GeyserConnection;
 import org.geysermc.geyser.api.event.EventBus;
 import org.geysermc.geyser.api.extension.ExtensionManager;
@@ -66,15 +65,9 @@ public interface GeyserApi extends GeyserApiBase {
      *
      * @return the extension manager
      */
+    @NonNull
     ExtensionManager extensionManager();
 
-    /**
-     * Gets the {@link CommandManager}.
-     *
-     * @return the command manager
-     */
-    CommandManager commandManager();
-
     /**
      * Provides an implementation for the specified API type.
      *
@@ -92,6 +85,7 @@ public interface GeyserApi extends GeyserApiBase {
      *
      * @return the event bus
      */
+    @NonNull
     EventBus eventBus();
 
     /**
@@ -100,6 +94,7 @@ public interface GeyserApi extends GeyserApiBase {
      *
      * @return the default remote server used within Geyser
      */
+    @NonNull
     RemoteServer defaultRemoteServer();
 
     /**
@@ -108,6 +103,7 @@ public interface GeyserApi extends GeyserApiBase {
      *
      * @return the listener used for Bedrock client connectins
      */
+    @NonNull
     BedrockListener bedrockListener();
 
     /**
@@ -115,6 +111,7 @@ public interface GeyserApi extends GeyserApiBase {
      *
      * @return the current geyser api instance
      */
+    @NonNull
     static GeyserApi api() {
         return Geyser.api(GeyserApi.class);
     }

api/geyser/src/main/java/org/geysermc/geyser/api/command/Command.java

@@ -27,6 +27,8 @@ package org.geysermc.geyser.api.command;
 
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.geysermc.geyser.api.GeyserApi;
+import org.geysermc.geyser.api.connection.GeyserConnection;
+import org.geysermc.geyser.api.extension.Extension;
 
 import java.util.Collections;
 import java.util.List;
@@ -104,19 +106,39 @@ public interface Command {
         return false;
     }
 
-    static <T extends CommandSource> Command.Builder<T> builder(Class<T> sourceType) {
+    /**
-        return GeyserApi.api().provider(Builder.class, sourceType);
+     * Creates a new {@link Command.Builder} used to construct commands.
+     *
+     * @param extension the extension
+     * @param <T> the source type
+     * @return a new command builder used to construct commands
+     */
+    static <T extends CommandSource> Command.Builder<T> builder(@NonNull Extension extension) {
+        return GeyserApi.api().provider(Builder.class, extension);
     }
 
     interface Builder<T extends CommandSource> {
 
+        /**
+         * Defines the source type to use for this command.
+         * <p>
+         * Command source types can be anything that extend
+         * {@link CommandSource}, such as {@link GeyserConnection}.
+         * This will guarantee that the source used in the executor
+         * is an instance of this source.
+         *
+         * @param sourceType the source type
+         * @return the builder
+         */
+        Builder<T> source(@NonNull Class<? extends T> sourceType);
+
         /**
          * Sets the command name.
          *
          * @param name the command name
          * @return the builder
          */
-        Builder<T> name(String name);
+        Builder<T> name(@NonNull String name);
 
         /**
          * Sets the command description.
@@ -124,7 +146,7 @@ public interface Command {
          * @param description the command description
          * @return the builder
          */
-        Builder<T> description(String description);
+        Builder<T> description(@NonNull String description);
 
         /**
          * Sets the permission node.
@@ -132,7 +154,7 @@ public interface Command {
          * @param permission the permission node
          * @return the builder
          */
-        Builder<T> permission(String permission);
+        Builder<T> permission(@NonNull String permission);
 
         /**
          * Sets the aliases.
@@ -140,7 +162,7 @@ public interface Command {
          * @param aliases the aliases
          * @return the builder
          */
-        Builder<T> aliases(List<String> aliases);
+        Builder<T> aliases(@NonNull List<String> aliases);
 
         /**
          * Sets if this command is designed to be used only by server operators.
@@ -164,7 +186,7 @@ public interface Command {
          * @param subCommands the subcommands
          * @return the builder
          */
-        Builder<T> subCommands(List<String> subCommands);
+        Builder<T> subCommands(@NonNull List<String> subCommands);
 
         /**
          * Sets if this command is bedrock only.
@@ -180,13 +202,14 @@ public interface Command {
          * @param executor the command executor
          * @return the builder
          */
-        Builder<T> executor(CommandExecutor<T> executor);
+        Builder<T> executor(@NonNull CommandExecutor<T> executor);
 
         /**
          * Builds the command.
          *
          * @return the command
          */
+        @NonNull
         Command build();
     }
 }

api/geyser/src/main/java/org/geysermc/geyser/api/event/lifecycle/GeyserDefineCommandsEvent.java

@@ -23,36 +23,35 @@
  * @link https://github.com/GeyserMC/Geyser
  */
 
-package org.geysermc.geyser.api.command;
+package org.geysermc.geyser.api.event.lifecycle;
 
 import org.checkerframework.checker.nullness.qual.NonNull;
+import org.geysermc.event.Event;
+import org.geysermc.geyser.api.command.Command;
 
 import java.util.Map;
 
 /**
- * Manages Bedrock commands within Geyser.
+ * Called when commands are defined within Geyser.
+ *
+ * This event allows you to register new commands using the {@link #register(Command)}
+ * method and retrieve the default commands defined.
  */
-public abstract class CommandManager {
+public interface GeyserDefineCommandsEvent extends Event {
 
     /**
-     * Registers the given {@link Command}.
+     * Registers the given {@link Command} into the Geyser
+     * command manager.
      *
      * @param command the command to register
      */
-    public abstract void register(@NonNull Command command);
+    void register(@NonNull Command command);
 
     /**
-     * Unregisters the given {@link Command}.
+     * Gets all the registered built-in {@link Command}s.
      *
-     * @param command the command to unregister
+     * @return all the registered built-in commands
-     */
-    public abstract void unregister(@NonNull Command command);
-
-    /**
-     * Gets all the registered {@link Command}s.
-     *
-     * @return all the registered commands
      */
     @NonNull
-    public abstract Map<String, Command> commands();
+    Map<String, Command> commands();
 }

api/geyser/src/main/java/org/geysermc/geyser/api/event/lifecycle/GeyserShutdownEvent.java

@@ -27,12 +27,11 @@ package org.geysermc.geyser.api.event.lifecycle;
 
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.geysermc.event.Event;
-import org.geysermc.geyser.api.command.CommandManager;
 import org.geysermc.geyser.api.event.EventBus;
 import org.geysermc.geyser.api.extension.ExtensionManager;
 
 /**
  * Called when Geyser is shutting down.
  */
-public record GeyserShutdownEvent(@NonNull ExtensionManager extensionManager, @NonNull CommandManager commandManager, @NonNull EventBus eventBus) implements Event {
+public record GeyserShutdownEvent(@NonNull ExtensionManager extensionManager, @NonNull EventBus eventBus) implements Event {
 }

api/geyser/src/main/java/org/geysermc/geyser/api/extension/ExtensionDescription.java

@@ -30,12 +30,20 @@ import org.checkerframework.checker.nullness.qual.NonNull;
 import java.util.List;
 
 /**
- * This is the Geyser extension description
+ * Represents the description of an {@link Extension}.
  */
 public interface ExtensionDescription {
 
     /**
-     * Gets the extension's name
+     * Gets the extension's id.
+     *
+     * @return the extension's id
+     */
+    @NonNull
+    String id();
+
+    /**
+     * Gets the extension's name.
      *
      * @return the extension's name
      */
@@ -43,7 +51,7 @@ public interface ExtensionDescription {
     String name();
 
     /**
-     * Gets the extension's main class
+     * Gets the extension's main class.
      *
      * @return the extension's main class
      */
@@ -51,7 +59,7 @@ public interface ExtensionDescription {
     String main();
 
     /**
-     * Gets the extension's api version
+     * Gets the extension's api version.
      *
      * @return the extension's api version
      */
@@ -59,7 +67,7 @@ public interface ExtensionDescription {
     String apiVersion();
 
     /**
-     * Gets the extension's description
+     * Gets the extension's description.
      *
      * @return the extension's description
      */
@@ -67,7 +75,7 @@ public interface ExtensionDescription {
     String version();
 
     /**
-     * Gets the extension's authors
+     * Gets the extension's authors.
      *
      * @return the extension's authors
      */

bootstrap/bungeecord/src/main/java/org/geysermc/geyser/platform/bungeecord/GeyserBungeePlugin.java

@@ -32,6 +32,8 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 import org.geysermc.common.PlatformType;
 import org.geysermc.geyser.GeyserBootstrap;
 import org.geysermc.geyser.GeyserImpl;
+import org.geysermc.geyser.api.command.Command;
+import org.geysermc.geyser.api.extension.Extension;
 import org.geysermc.geyser.api.network.AuthType;
 import org.geysermc.geyser.command.GeyserCommandManager;
 import org.geysermc.geyser.configuration.GeyserConfiguration;
@@ -49,6 +51,7 @@ import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.Map;
 import java.util.UUID;
 import java.util.logging.Level;
 
@@ -149,8 +152,15 @@ public class GeyserBungeePlugin extends Plugin implements GeyserBootstrap {
             this.geyserBungeePingPassthrough = new GeyserBungeePingPassthrough(getProxy());
         }
 
-        this.getProxy().getPluginManager().registerCommand(this, new GeyserBungeeCommandExecutor("geyser", geyser, geyserCommandManager.getCommands()));
+        this.getProxy().getPluginManager().registerCommand(this, new GeyserBungeeCommandExecutor("geyser", this.geyser, this.geyserCommandManager.getCommands()));
-        this.getProxy().getPluginManager().registerCommand(this, new GeyserBungeeCommandExecutor("geyserext", geyser, geyserCommandManager.commands()));
+        for (Map.Entry<Extension, Map<String, Command>> entry : this.geyserCommandManager.extensionCommands().entrySet()) {
+            Map<String, Command> commands = entry.getValue();
+            if (commands.isEmpty()) {
+                continue;
+            }
+
+            this.getProxy().getPluginManager().registerCommand(this, new GeyserBungeeCommandExecutor(entry.getKey().description().id(), this.geyser, commands));
+        }
     }
 
     @Override

bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/GeyserSpigotPlugin.java

@@ -32,9 +32,11 @@ import com.viaversion.viaversion.api.protocol.version.ProtocolVersion;
 import io.netty.buffer.ByteBuf;
 import me.lucko.commodore.CommodoreProvider;
 import org.bukkit.Bukkit;
+import org.bukkit.command.CommandMap;
 import org.bukkit.command.PluginCommand;
 import org.bukkit.permissions.Permission;
 import org.bukkit.permissions.PermissionDefault;
+import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.java.JavaPlugin;
 import org.geysermc.common.PlatformType;
 import org.geysermc.geyser.Constants;
@@ -42,6 +44,7 @@ import org.geysermc.geyser.GeyserBootstrap;
 import org.geysermc.geyser.GeyserImpl;
 import org.geysermc.geyser.adapters.spigot.SpigotAdapters;
 import org.geysermc.geyser.api.command.Command;
+import org.geysermc.geyser.api.extension.Extension;
 import org.geysermc.geyser.api.network.AuthType;
 import org.geysermc.geyser.command.GeyserCommandManager;
 import org.geysermc.geyser.configuration.GeyserConfiguration;
@@ -62,6 +65,8 @@ import org.geysermc.geyser.util.FileUtils;
 
 import java.io.File;
 import java.io.IOException;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
 import java.net.SocketAddress;
 import java.nio.file.Path;
 import java.util.List;
@@ -269,13 +274,32 @@ public class GeyserSpigotPlugin extends JavaPlugin implements GeyserBootstrap {
 
         PluginCommand geyserCommand = this.getCommand("geyser");
         geyserCommand.setExecutor(new GeyserSpigotCommandExecutor(geyser, geyserCommandManager.getCommands()));
-        PluginCommand geyserExtCommand = this.getCommand("geyserext");
+
-        geyserExtCommand.setExecutor(new GeyserSpigotCommandExecutor(geyser, geyserCommandManager.getCommands()));
+        CommandMap commandMap = GeyserSpigotCommandManager.getCommandMap();
+        for (Map.Entry<Extension, Map<String, Command>> entry : this.geyserCommandManager.extensionCommands().entrySet()) {
+            Map<String, Command> commands = entry.getValue();
+            if (commands.isEmpty()) {
+                continue;
+            }
+
+            // Thanks again, Bukkit
+            try {
+                Constructor<PluginCommand> constructor = PluginCommand.class.getDeclaredConstructor(String.class, Plugin.class);
+                constructor.setAccessible(true);
+
+                PluginCommand pluginCommand = constructor.newInstance(entry.getKey().description().id(), this);
+                pluginCommand.setExecutor(new GeyserSpigotCommandExecutor(this.geyser, commands));
+                pluginCommand.setDescription("The main command for the " + entry.getKey().name() + " Geyser extension!");
+                commandMap.register(entry.getKey().description().id(), "geyserext", pluginCommand);
+            } catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException ex) {
+                this.geyserLogger.error("Failed to construct PluginCommand for extension " + entry.getKey().description().name(), ex);
+            }
+        }
 
         if (!INITIALIZED) {
             // Register permissions so they appear in, for example, LuckPerms' UI
             // Re-registering permissions throws an error
-            for (Map.Entry<String, Command> entry : geyserCommandManager.getCommands().entrySet()) {
+            for (Map.Entry<String, Command> entry : geyserCommandManager.commands().entrySet()) {
                 Command command = entry.getValue();
                 if (command.aliases().contains(entry.getKey())) {
                     // Don't register aliases
@@ -286,6 +310,26 @@ public class GeyserSpigotPlugin extends JavaPlugin implements GeyserBootstrap {
                         GeyserLocale.getLocaleStringLog(command.description()),
                         command.isSuggestedOpOnly() ? PermissionDefault.OP : PermissionDefault.TRUE));
             }
+
+            // Register permissions for extension commands
+            for (Map.Entry<Extension, Map<String, Command>> commandEntry : this.geyserCommandManager.extensionCommands().entrySet()) {
+                for (Map.Entry<String, Command> entry : commandEntry.getValue().entrySet()) {
+                    Command command = entry.getValue();
+                    if (command.aliases().contains(entry.getKey())) {
+                        // Don't register aliases
+                        continue;
+                    }
+
+                    if (command.permission().isBlank()) {
+                        continue;
+                    }
+
+                    Bukkit.getPluginManager().addPermission(new Permission(command.permission(),
+                            GeyserLocale.getLocaleStringLog(command.description()),
+                            command.isSuggestedOpOnly() ? PermissionDefault.OP : PermissionDefault.TRUE));
+                }
+            }
+
             Bukkit.getPluginManager().addPermission(new Permission(Constants.UPDATE_PERMISSION,
                     "Whether update notifications can be seen", PermissionDefault.OP));
 

bootstrap/spigot/src/main/java/org/geysermc/geyser/platform/spigot/command/GeyserSpigotCommandManager.java

@@ -65,4 +65,8 @@ public class GeyserSpigotCommandManager extends GeyserCommandManager {
         Command cmd = COMMAND_MAP.getCommand(command.replace("/", ""));
         return cmd != null ? cmd.getDescription() : "";
     }
+
+    public static CommandMap getCommandMap() {
+        return COMMAND_MAP;
+    }
 }

bootstrap/spigot/src/main/resources/plugin.yml

@@ -9,6 +9,3 @@ commands:
   geyser:
     description: The main command for Geyser.
     usage: /geyser <subcommand>
-  geyserext:
-    description: The command any extensions can register to.
-    usage: /geyserext <subcommand>

bootstrap/sponge/src/main/java/org/geysermc/geyser/platform/sponge/GeyserSpongePlugin.java

@@ -29,6 +29,8 @@ import com.google.inject.Inject;
 import org.geysermc.common.PlatformType;
 import org.geysermc.geyser.GeyserBootstrap;
 import org.geysermc.geyser.GeyserImpl;
+import org.geysermc.geyser.api.command.Command;
+import org.geysermc.geyser.api.extension.Extension;
 import org.geysermc.geyser.command.GeyserCommandManager;
 import org.geysermc.geyser.configuration.GeyserConfiguration;
 import org.geysermc.geyser.dump.BootstrapDumpInfo;
@@ -50,6 +52,7 @@ import java.io.File;
 import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.nio.file.Path;
+import java.util.Map;
 import java.util.UUID;
 
 @Plugin(id = "geyser", name = GeyserImpl.NAME + "-Sponge", version = GeyserImpl.VERSION, url = "https://geysermc.org", authors = "GeyserMC")
@@ -122,7 +125,15 @@ public class GeyserSpongePlugin implements GeyserBootstrap {
         this.geyserCommandManager = new GeyserSpongeCommandManager(Sponge.getCommandManager(), geyser);
         this.geyserCommandManager.init();
         Sponge.getCommandManager().register(this, new GeyserSpongeCommandExecutor(geyser, geyserCommandManager.getCommands()), "geyser");
-        Sponge.getCommandManager().register(this, new GeyserSpongeCommandExecutor(geyser, geyserCommandManager.commands()), "geyserext");
+
+        for (Map.Entry<Extension, Map<String, Command>> entry : this.geyserCommandManager.extensionCommands().entrySet()) {
+            Map<String, Command> commands = entry.getValue();
+            if (commands.isEmpty()) {
+                continue;
+            }
+
+            Sponge.getCommandManager().register(this, new GeyserSpongeCommandExecutor(this.geyser, commands), entry.getKey().description().id());
+        }
     }
 
     @Override

bootstrap/velocity/src/main/java/org/geysermc/geyser/platform/velocity/GeyserVelocityPlugin.java

@@ -39,6 +39,8 @@ import net.kyori.adventure.util.Codec;
 import org.geysermc.common.PlatformType;
 import org.geysermc.geyser.GeyserBootstrap;
 import org.geysermc.geyser.GeyserImpl;
+import org.geysermc.geyser.api.command.Command;
+import org.geysermc.geyser.api.extension.Extension;
 import org.geysermc.geyser.api.network.AuthType;
 import org.geysermc.geyser.command.GeyserCommandManager;
 import org.geysermc.geyser.configuration.GeyserConfiguration;
@@ -58,6 +60,7 @@ import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.Map;
 import java.util.UUID;
 
 @Plugin(id = "geyser", name = GeyserImpl.NAME + "-Velocity", version = GeyserImpl.VERSION, url = "https://geysermc.org", authors = "GeyserMC")
@@ -159,7 +162,15 @@ public class GeyserVelocityPlugin implements GeyserBootstrap {
         this.geyserCommandManager.init();
 
         this.commandManager.register("geyser", new GeyserVelocityCommandExecutor(geyser, geyserCommandManager.getCommands()));
-        this.commandManager.register("geyserext", new GeyserVelocityCommandExecutor(geyser, geyserCommandManager.commands()));
+        for (Map.Entry<Extension, Map<String, Command>> entry : this.geyserCommandManager.extensionCommands().entrySet()) {
+            Map<String, Command> commands = entry.getValue();
+            if (commands.isEmpty()) {
+                continue;
+            }
+
+            this.commandManager.register(entry.getKey().description().id(), new GeyserVelocityCommandExecutor(this.geyser, commands));
+        }
+
         if (geyserConfig.isLegacyPingPassthrough()) {
             this.geyserPingPassthrough = GeyserLegacyPingPassthrough.init(geyser);
         } else {

core/src/main/java/org/geysermc/geyser/GeyserImpl.java

@@ -547,7 +547,7 @@ public class GeyserImpl implements GeyserApi {
 
         ResourcePack.PACKS.clear();
 
-        this.eventBus.fire(new GeyserShutdownEvent(this.extensionManager, this.commandManager(), this.eventBus));
+        this.eventBus.fire(new GeyserShutdownEvent(this.extensionManager, this.eventBus));
         this.extensionManager.disableExtensions();
 
         bootstrap.getGeyserLogger().info(GeyserLocale.getLocaleStringLog("geyser.core.shutdown.done"));
@@ -572,11 +572,12 @@ public class GeyserImpl implements GeyserApi {
     }
 
     @Override
+    @NonNull
     public GeyserExtensionManager extensionManager() {
         return this.extensionManager;
     }
 
-    @Override
+    @NonNull
     public GeyserCommandManager commandManager() {
         return this.bootstrap.getGeyserCommandManager();
     }
@@ -587,15 +588,18 @@ public class GeyserImpl implements GeyserApi {
     }
 
     @Override
+    @NonNull
     public EventBus eventBus() {
         return this.eventBus;
     }
 
+    @NonNull
     public RemoteServer defaultRemoteServer() {
         return getConfig().getRemote();
     }
 
     @Override
+    @NonNull
     public BedrockListener bedrockListener() {
         return getConfig().getBedrock();
     }

core/src/main/java/org/geysermc/geyser/command/GeyserCommandManager.java

@@ -33,30 +33,46 @@ import org.geysermc.common.PlatformType;
 import org.geysermc.geyser.GeyserImpl;
 import org.geysermc.geyser.api.command.Command;
 import org.geysermc.geyser.api.command.CommandExecutor;
-import org.geysermc.geyser.api.command.CommandManager;
 import org.geysermc.geyser.api.command.CommandSource;
-import org.geysermc.geyser.command.defaults.*;
+import org.geysermc.geyser.api.event.lifecycle.GeyserDefineCommandsEvent;
+import org.geysermc.geyser.api.extension.Extension;
+import org.geysermc.geyser.command.defaults.AdvancedTooltipsCommand;
+import org.geysermc.geyser.command.defaults.AdvancementsCommand;
+import org.geysermc.geyser.command.defaults.ConnectionTestCommand;
+import org.geysermc.geyser.command.defaults.DumpCommand;
+import org.geysermc.geyser.command.defaults.ExtensionsCommand;
+import org.geysermc.geyser.command.defaults.HelpCommand;
+import org.geysermc.geyser.command.defaults.ListCommand;
+import org.geysermc.geyser.command.defaults.OffhandCommand;
+import org.geysermc.geyser.command.defaults.ReloadCommand;
+import org.geysermc.geyser.command.defaults.SettingsCommand;
+import org.geysermc.geyser.command.defaults.StatisticsCommand;
+import org.geysermc.geyser.command.defaults.StopCommand;
+import org.geysermc.geyser.command.defaults.VersionCommand;
+import org.geysermc.geyser.event.type.GeyserDefineCommandsEventImpl;
+import org.geysermc.geyser.extension.command.GeyserExtensionCommand;
 import org.geysermc.geyser.session.GeyserSession;
 import org.geysermc.geyser.text.GeyserLocale;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 
 @RequiredArgsConstructor
-public abstract class GeyserCommandManager extends CommandManager {
+public abstract class GeyserCommandManager {
 
     @Getter
     private final Map<String, Command> commands = new Object2ObjectOpenHashMap<>(12);
-    private final Map<String, Command> extensionCommands = new Object2ObjectOpenHashMap<>(0);
+    private final Map<Extension, Map<String, Command>> extensionCommands = new Object2ObjectOpenHashMap<>(0);
 
     private final GeyserImpl geyser;
 
     public void init() {
-        registerBuiltInCommand(new HelpCommand(geyser, "help", "geyser.commands.help.desc", "geyser.command.help", "geyser", commands));
+        registerBuiltInCommand(new HelpCommand(geyser, "help", "geyser.commands.help.desc", "geyser.command.help", "geyser", this.commands));
         registerBuiltInCommand(new ListCommand(geyser, "list", "geyser.commands.list.desc", "geyser.command.list"));
         registerBuiltInCommand(new ReloadCommand(geyser, "reload", "geyser.commands.reload.desc", "geyser.command.reload"));
         registerBuiltInCommand(new OffhandCommand(geyser, "offhand", "geyser.commands.offhand.desc", "geyser.command.offhand"));
@@ -67,11 +83,32 @@ public abstract class GeyserCommandManager extends CommandManager {
         registerBuiltInCommand(new AdvancementsCommand("advancements", "geyser.commands.advancements.desc", "geyser.command.advancements"));
         registerBuiltInCommand(new AdvancedTooltipsCommand("tooltips", "geyser.commands.advancedtooltips.desc", "geyser.command.tooltips"));
         registerBuiltInCommand(new ConnectionTestCommand(geyser, "connectiontest", "geyser.commands.connectiontest.desc", "geyser.command.connectiontest"));
-        if (GeyserImpl.getInstance().getPlatformType() == PlatformType.STANDALONE) {
+        if (this.geyser.getPlatformType() == PlatformType.STANDALONE) {
             registerBuiltInCommand(new StopCommand(geyser, "stop", "geyser.commands.stop.desc", "geyser.command.stop"));
         }
 
-        register(new HelpCommand(geyser, "help", "geyser.commands.exthelp.desc", "geyser.command.exthelp", "geyserext", extensionCommands));
+        if (this.geyser.extensionManager().extensions().size() > 0) {
+            registerBuiltInCommand(new ExtensionsCommand(this.geyser, "extensions", "geyser.commands.extensions.desc", "geyser.command.extensions"));
+        }
+
+        GeyserDefineCommandsEvent defineCommandsEvent = new GeyserDefineCommandsEventImpl(this.commands) {
+
+            @Override
+            public void register(@NonNull Command command) {
+                if (!(command instanceof GeyserExtensionCommand extensionCommand)) {
+                    throw new IllegalArgumentException("Expected GeyserExtensionCommand as part of command registration but got " + command + "! Did you use the Command builder properly?");
+                }
+
+                registerExtensionCommand(extensionCommand.extension(), extensionCommand);
+            }
+        };
+
+        this.geyser.eventBus().fire(defineCommandsEvent);
+
+        // Register help commands for all extensions with commands
+        for (Map.Entry<Extension, Map<String, Command>> entry : this.extensionCommands.entrySet()) {
+            registerExtensionCommand(entry.getKey(), new HelpCommand(this.geyser, "help", "geyser.commands.exthelp.desc", "geyser.command.exthelp", entry.getKey().description().id(), entry.getValue()));
+        }
     }
 
     /**
@@ -81,9 +118,8 @@ public abstract class GeyserCommandManager extends CommandManager {
         register(command, this.commands);
     }
 
-    @Override
+    public void registerExtensionCommand(@NonNull Extension extension, @NonNull Command command) {
-    public void register(@NonNull Command command) {
+        register(command, this.extensionCommands.computeIfAbsent(extension, e -> new HashMap<>()));
-        register(command, this.extensionCommands);
     }
 
     private void register(Command command, Map<String, Command> commands) {
@@ -99,32 +135,30 @@ public abstract class GeyserCommandManager extends CommandManager {
         }
     }
 
-    @Override
+    @NotNull
-    public void unregister(@NonNull Command command) {
+    public Map<String, Command> commands() {
-        this.extensionCommands.remove(command.name(), command);
+        return Collections.unmodifiableMap(this.commands);
-
-        if (command.aliases().isEmpty()) {
-            return;
-        }
-
-        for (String alias : command.aliases()) {
-            this.extensionCommands.remove(alias, command);
-        }
     }
 
     @NotNull
-    @Override
+    public Map<Extension, Map<String, Command>> extensionCommands() {
-    public Map<String, Command> commands() {
         return Collections.unmodifiableMap(this.extensionCommands);
     }
 
     public boolean runCommand(GeyserCommandSource sender, String command) {
-        boolean extensionCommand = command.startsWith("geyserext ");
+        Extension extension = null;
-        if (!command.startsWith("geyser ") && !extensionCommand) {
+        for (Extension loopedExtension : this.extensionCommands.keySet()) {
+            if (command.startsWith(loopedExtension.description().id() + " ")) {
+                extension = loopedExtension;
+                break;
+            }
+        }
+
+        if (!command.startsWith("geyser ") && extension == null) {
             return false;
         }
 
-        command = command.trim().replace(extensionCommand ? "geyserext " : "geyser ", "");
+        command = command.trim().replace(extension != null ? extension.description().id() + " " : "geyser ", "");
         String label;
         String[] args;
 
@@ -137,9 +171,9 @@ public abstract class GeyserCommandManager extends CommandManager {
             args = argLine.contains(" ") ? argLine.split(" ") : new String[] { argLine };
         }
 
-        Command cmd = (extensionCommand ? this.extensionCommands : this.commands).get(label);
+        Command cmd = (extension != null ? this.extensionCommands.getOrDefault(extension, Collections.emptyMap()) : this.commands).get(label);
         if (cmd == null) {
-            geyser.getLogger().error(GeyserLocale.getLocaleStringLog("geyser.commands.invalid"));
+            sender.sendMessage(GeyserLocale.getLocaleStringLog("geyser.commands.invalid"));
             return false;
         }
 
@@ -168,7 +202,8 @@ public abstract class GeyserCommandManager extends CommandManager {
 
     @RequiredArgsConstructor
     public static class CommandBuilder<T extends CommandSource> implements Command.Builder<T> {
-        private final Class<T> sourceType;
+        private final Extension extension;
+        private Class<? extends T> sourceType;
         private String name;
         private String description = "";
         private String permission = "";
@@ -179,22 +214,28 @@ public abstract class GeyserCommandManager extends CommandManager {
         private boolean bedrockOnly;
         private CommandExecutor<T> executor;
 
-        public CommandBuilder<T> name(String name) {
+        @Override
+        public Command.Builder<T> source(@NonNull Class<? extends T> sourceType) {
+            this.sourceType = sourceType;
+            return this;
+        }
+
+        public CommandBuilder<T> name(@NonNull String name) {
             this.name = name;
             return this;
         }
 
-        public CommandBuilder<T> description(String description) {
+        public CommandBuilder<T> description(@NonNull String description) {
             this.description = description;
             return this;
         }
 
-        public CommandBuilder<T> permission(String permission) {
+        public CommandBuilder<T> permission(@NonNull String permission) {
             this.permission = permission;
             return this;
         }
 
-        public CommandBuilder<T> aliases(List<String> aliases) {
+        public CommandBuilder<T> aliases(@NonNull List<String> aliases) {
             this.aliases = aliases;
             return this;
         }
@@ -210,7 +251,7 @@ public abstract class GeyserCommandManager extends CommandManager {
             return this;
         }
 
-        public CommandBuilder<T> subCommands(List<String> subCommands) {
+        public CommandBuilder<T> subCommands(@NonNull List<String> subCommands) {
             this.subCommands = subCommands;
             return this;
         }
@@ -220,22 +261,27 @@ public abstract class GeyserCommandManager extends CommandManager {
             return this;
         }
 
-        public CommandBuilder<T> executor(CommandExecutor<T> executor) {
+        public CommandBuilder<T> executor(@NonNull CommandExecutor<T> executor) {
             this.executor = executor;
             return this;
         }
 
-        public GeyserCommand build() {
+        @NonNull
+        public GeyserExtensionCommand build() {
             if (this.name == null || this.name.isBlank()) {
                 throw new IllegalArgumentException("Command cannot be null or blank!");
             }
 
-            return new GeyserCommand(this.name, this.description, this.permission) {
+            if (this.sourceType == null) {
+                throw new IllegalArgumentException("Source type was not defined for command " + this.name + " in extension " + this.extension.name());
+            }
+
+            return new GeyserExtensionCommand(this.extension, this.name, this.description, this.permission) {
 
                 @SuppressWarnings("unchecked")
                 @Override
                 public void execute(@Nullable GeyserSession session, GeyserCommandSource sender, String[] args) {
-                    Class<T> sourceType = CommandBuilder.this.sourceType;
+                    Class<? extends T> sourceType = CommandBuilder.this.sourceType;
                     CommandExecutor<T> executor = CommandBuilder.this.executor;
                     if (sourceType.isInstance(session)) {
                         executor.execute((T) session, this, args);

core/src/main/java/org/geysermc/geyser/command/defaults/HelpCommand.java

@@ -66,19 +66,19 @@ public class HelpCommand extends GeyserCommand {
         String header = GeyserLocale.getPlayerLocaleString("geyser.commands.help.header", sender.locale(), page, maxPage);
         sender.sendMessage(header);
 
-        for (Map.Entry<String, Command> entry : commands.entrySet()) {
+        this.commands.entrySet().stream().sorted(Map.Entry.comparingByKey()).forEach(entry -> {
             Command cmd = entry.getValue();
 
             // Standalone hack-in since it doesn't have a concept of permissions
             if (geyser.getPlatformType() == PlatformType.STANDALONE || sender.hasPermission(cmd.permission())) {
                 // Only list commands the player can actually run
                 if (cmd.isBedrockOnly() && session == null) {
-                    continue;
+                    return;
                 }
 
                 sender.sendMessage(ChatColor.YELLOW + "/" + baseCommand + " " + entry.getKey() + ChatColor.WHITE + ": " +
                         GeyserLocale.getPlayerLocaleString(cmd.description(), sender.locale()));
             }
-        }
+        });
     }
 }

core/src/main/java/org/geysermc/geyser/event/type/GeyserDefineCommandsEventImpl.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2019-2022 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.geyser.event.type;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.geysermc.geyser.api.command.Command;
+import org.geysermc.geyser.api.event.lifecycle.GeyserDefineCommandsEvent;
+
+import java.util.Collections;
+import java.util.Map;
+
+public abstract class GeyserDefineCommandsEventImpl implements GeyserDefineCommandsEvent {
+    private final Map<String, Command> commands;
+
+    public GeyserDefineCommandsEventImpl(Map<String, Command> commands) {
+        this.commands = commands;
+    }
+
+    @Override
+    public @NonNull Map<String, Command> commands() {
+        return Collections.unmodifiableMap(this.commands);
+    }
+}

core/src/main/java/org/geysermc/geyser/event/type/GeyserDefineCustomItemsEventImpl.java

@@ -36,11 +36,11 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
-public abstract class DefineCustomItemsEvent implements GeyserDefineCustomItemsEvent {
+public abstract class GeyserDefineCustomItemsEventImpl implements GeyserDefineCustomItemsEvent {
     private final Multimap<String, CustomItemData> customItems;
     private final List<NonVanillaCustomItemData> nonVanillaCustomItems;
 
-    public DefineCustomItemsEvent(Multimap<String, CustomItemData> customItems, List<NonVanillaCustomItemData> nonVanillaCustomItems) {
+    public GeyserDefineCustomItemsEventImpl(Multimap<String, CustomItemData> customItems, List<NonVanillaCustomItemData> nonVanillaCustomItems) {
         this.customItems = customItems;
         this.nonVanillaCustomItems = nonVanillaCustomItems;
     }

core/src/main/java/org/geysermc/geyser/extension/GeyserExtensionDescription.java

@@ -33,7 +33,7 @@ import org.yaml.snakeyaml.Yaml;
 import java.io.Reader;
 import java.util.*;
 
-public record GeyserExtensionDescription(String name, String main, String apiVersion, String version, List<String> authors) implements ExtensionDescription {
+public record GeyserExtensionDescription(String id, String name, String main, String apiVersion, String version, List<String> authors) implements ExtensionDescription {
     @SuppressWarnings("unchecked")
     public static GeyserExtensionDescription fromYaml(Reader reader) throws InvalidDescriptionException {
         DumperOptions dumperOptions = new DumperOptions();
@@ -42,6 +42,11 @@ public record GeyserExtensionDescription(String name, String main, String apiVer
         Yaml yaml = new Yaml(dumperOptions);
         Map<String, Object> yamlMap = yaml.loadAs(reader, LinkedHashMap.class);
 
+        String id = ((String) yamlMap.get("id")).replaceAll("[^A-Za-z0-9 _.-]", "");
+        if (id.isBlank()) {
+            throw new InvalidDescriptionException("Invalid extension id, cannot be empty");
+        }
+
         String name = ((String) yamlMap.get("name")).replaceAll("[^A-Za-z0-9 _.-]", "");
         if (name.isBlank()) {
             throw new InvalidDescriptionException("Invalid extension name, cannot be empty");
@@ -72,6 +77,6 @@ public record GeyserExtensionDescription(String name, String main, String apiVer
             }
         }
 
-        return new GeyserExtensionDescription(name, main, apiVersion, version, authors);
+        return new GeyserExtensionDescription(id, name, main, apiVersion, version, Collections.unmodifiableList(authors));
     }
 }

core/src/main/java/org/geysermc/geyser/extension/command/GeyserExtensionCommand.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2019-2022 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.geyser.extension.command;
+
+import org.geysermc.geyser.api.extension.Extension;
+import org.geysermc.geyser.command.GeyserCommand;
+
+public abstract class GeyserExtensionCommand extends GeyserCommand {
+    private final Extension extension;
+
+    public GeyserExtensionCommand(Extension extension, String name, String description, String permission) {
+        super(name, description, permission);
+
+        this.extension = extension;
+    }
+
+    public Extension extension() {
+        return this.extension;
+    }
+}

core/src/main/java/org/geysermc/geyser/registry/loader/ProviderRegistryLoader.java

@@ -26,7 +26,7 @@
 package org.geysermc.geyser.registry.loader;
 
 import org.geysermc.geyser.api.command.Command;
-import org.geysermc.geyser.api.command.CommandSource;
+import org.geysermc.geyser.api.extension.Extension;
 import org.geysermc.geyser.api.item.custom.CustomItemData;
 import org.geysermc.geyser.api.item.custom.CustomItemOptions;
 import org.geysermc.geyser.api.item.custom.NonVanillaCustomItemData;
@@ -43,10 +43,9 @@ import java.util.Map;
  */
 public class ProviderRegistryLoader implements RegistryLoader<Map<Class<?>, ProviderSupplier>, Map<Class<?>, ProviderSupplier>> {
 
-    @SuppressWarnings("unchecked")
     @Override
     public Map<Class<?>, ProviderSupplier> load(Map<Class<?>, ProviderSupplier> providers) {
-        providers.put(Command.Builder.class, args -> new GeyserCommandManager.CommandBuilder<>((Class<? extends CommandSource>) args[0]));
+        providers.put(Command.Builder.class, args -> new GeyserCommandManager.CommandBuilder<>((Extension) args[0]));
         providers.put(CustomItemData.Builder.class, args -> new GeyserCustomItemData.CustomItemDataBuilder());
         providers.put(CustomItemOptions.Builder.class, args -> new GeyserCustomItemOptions.CustomItemOptionsBuilder());
         providers.put(NonVanillaCustomItemData.Builder.class, args -> new GeyserNonVanillaCustomItemData.NonVanillaCustomItemDataBuilder());

core/src/main/java/org/geysermc/geyser/registry/populator/ItemRegistryPopulator.java

@@ -48,11 +48,10 @@ import it.unimi.dsi.fastutil.objects.*;
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.geysermc.geyser.GeyserBootstrap;
 import org.geysermc.geyser.GeyserImpl;
-import org.geysermc.geyser.api.event.lifecycle.GeyserDefineCustomItemsEvent;
 import org.geysermc.geyser.api.item.custom.CustomItemData;
 import org.geysermc.geyser.api.item.custom.CustomItemOptions;
 import org.geysermc.geyser.api.item.custom.NonVanillaCustomItemData;
-import org.geysermc.geyser.event.type.DefineCustomItemsEvent;
+import org.geysermc.geyser.event.type.GeyserDefineCustomItemsEventImpl;
 import org.geysermc.geyser.inventory.item.StoredItemMappings;
 import org.geysermc.geyser.item.GeyserCustomMappingData;
 import org.geysermc.geyser.item.mappings.MappingsConfigReader;
@@ -109,7 +108,7 @@ public class ItemRegistryPopulator {
             });
 
             nonVanillaCustomItems = new ObjectArrayList<>();
-            GeyserImpl.getInstance().eventBus().fire(new DefineCustomItemsEvent(customItems, nonVanillaCustomItems) {
+            GeyserImpl.getInstance().eventBus().fire(new GeyserDefineCustomItemsEventImpl(customItems, nonVanillaCustomItems) {
                 @Override
                 public boolean register(@NonNull String identifier, @NonNull CustomItemData customItemData) {
                     if (CustomItemRegistryPopulator.initialCheck(identifier, customItemData, items)) {