Spigot: enable command completions for /geyser

bootstrap/spigot/pom.xml

@@ -19,6 +19,11 @@
             <id>viaversion-repo</id>
             <url>https://repo.viaversion.com</url>
         </repository>
+        <repository>
+            <!-- For Commodore -->
+            <id>minecraft-repo</id>
+            <url>https://libraries.minecraft.net/</url>
+        </repository>
     </repositories>
 
     <dependencies>
@@ -34,6 +39,12 @@
             <version>1.18.1-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>io.papermc.paper</groupId>
+            <artifactId>paper-mojangapi</artifactId>
+            <version>1.18.1-R0.1-SNAPSHOT</version>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>com.viaversion</groupId>
             <artifactId>viaversion</artifactId>
@@ -45,6 +56,12 @@
             <artifactId>spigot-all</artifactId>
             <version>1.4-SNAPSHOT</version>
         </dependency>
+        <dependency>
+            <groupId>me.lucko</groupId>
+            <artifactId>commodore</artifactId>
+            <version>1.13</version>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
     <build>
         <finalName>${outputName}-Spigot</finalName>
@@ -95,6 +112,10 @@
                                     <pattern>org.objectweb.asm</pattern>
                                     <shadedPattern>org.geysermc.geyser.platform.spigot.shaded.asm</shadedPattern>
                                 </relocation>
+                                <relocation>
+                                    <pattern>me.lucko.commodore</pattern>
+                                    <shadedPattern>org.geysermc.geyser.platform.spigot.shaded.commodore</shadedPattern>
+                                </relocation>
                             </relocations>
                         </configuration>
                     </execution>
@@ -118,6 +139,7 @@
                             <exclude>io.netty:netty-codec-dns:*</exclude>
                             <exclude>io.netty:netty-resolver-dns:*</exclude>
                             <exclude>io.netty:netty-resolver-dns-native-macos:*</exclude>
+                            <exclude>com.mojang:*</exclude> <!-- Commodore includes Brigadier -->
                         </excludes>
                     </artifactSet>
                 </configuration>

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

@@ -25,11 +25,15 @@
 
 package org.geysermc.geyser.platform.spigot;
 
+import com.mojang.brigadier.builder.LiteralArgumentBuilder;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.data.MappingData;
 import com.viaversion.viaversion.api.protocol.ProtocolPathEntry;
 import com.viaversion.viaversion.api.protocol.version.ProtocolVersion;
+import me.lucko.commodore.Commodore;
+import me.lucko.commodore.CommodoreProvider;
 import org.bukkit.Bukkit;
+import org.bukkit.command.PluginCommand;
 import org.bukkit.plugin.java.JavaPlugin;
 import org.geysermc.common.PlatformType;
 import org.geysermc.geyser.Constants;
@@ -43,6 +47,7 @@ import org.geysermc.geyser.level.WorldManager;
 import org.geysermc.geyser.network.MinecraftProtocol;
 import org.geysermc.geyser.ping.GeyserLegacyPingPassthrough;
 import org.geysermc.geyser.ping.IGeyserPingPassthrough;
+import org.geysermc.geyser.platform.spigot.command.GeyserPaperCommandListener;
 import org.geysermc.geyser.platform.spigot.command.GeyserSpigotCommandExecutor;
 import org.geysermc.geyser.platform.spigot.command.GeyserSpigotCommandManager;
 import org.geysermc.geyser.platform.spigot.command.SpigotCommandSender;
@@ -234,7 +239,29 @@ public class GeyserSpigotPlugin extends JavaPlugin implements GeyserBootstrap {
 
         Bukkit.getServer().getPluginManager().registerEvents(new GeyserPistonListener(geyser, this.geyserWorldManager), this);
 
-        this.getCommand("geyser").setExecutor(new GeyserSpigotCommandExecutor(geyser));
+        PluginCommand pluginCommand = this.getCommand("geyser");
+        pluginCommand.setExecutor(new GeyserSpigotCommandExecutor(geyser));
+
+        boolean brigadierSupported = CommodoreProvider.isSupported();
+        geyserLogger.debug("Brigadier supported? " + brigadierSupported);
+        if (brigadierSupported) {
+            // Enable command completions if supported
+            // This is beneficial because this is sent over the network and Bedrock can see it
+            Commodore commodore = CommodoreProvider.getCommodore(this);
+            LiteralArgumentBuilder<?> builder = LiteralArgumentBuilder.literal("geyser");
+            for (String command : geyserCommandManager.getCommands().keySet()) {
+                builder.then(LiteralArgumentBuilder.literal(command));
+            }
+            commodore.register(pluginCommand, builder);
+
+            try {
+                Class.forName("com.destroystokyo.paper.event.brigadier.AsyncPlayerSendCommandsEvent");
+                Bukkit.getServer().getPluginManager().registerEvents(new GeyserPaperCommandListener(), this);
+                geyserLogger.debug("Successfully registered AsyncPlayerSendCommandsEvent listener.");
+            } catch (ClassNotFoundException e) {
+                geyserLogger.debug("Not registering AsyncPlayerSendCommandsEvent listener.");
+            }
+        }
 
         // Check to ensure the current setup can support the protocol version Geyser uses
         GeyserSpigotVersionChecker.checkForSupportedProtocol(geyserLogger, isViaVersion);

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

@@ -0,0 +1,87 @@
+/*
+ * 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.platform.spigot.command;
+
+import com.destroystokyo.paper.event.brigadier.AsyncPlayerSendCommandsEvent;
+import com.mojang.brigadier.tree.CommandNode;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.geysermc.geyser.GeyserImpl;
+import org.geysermc.geyser.command.GeyserCommand;
+
+import java.net.InetSocketAddress;
+import java.util.Iterator;
+import java.util.Map;
+
+public final class GeyserPaperCommandListener implements Listener {
+
+    @EventHandler
+    @SuppressWarnings("deprecation") // Used to indicate an unstable event
+    public void onCommandSend(AsyncPlayerSendCommandsEvent<?> event) {
+        // Documentation says to check (event.isAsynchronous() || !event.hasFiredAsync()), but as of Paper 1.18.2
+        // event.hasFiredAsync is never true
+        if (event.isAsynchronous()) {
+            CommandNode<?> geyserBrigadier = event.getCommandNode().getChild("geyser");
+            if (geyserBrigadier != null) {
+                Player player = event.getPlayer();
+                boolean isJavaPlayer = isProbablyJavaPlayer(player);
+                Map<String, GeyserCommand> commands = GeyserImpl.getInstance().getCommandManager().getCommands();
+                Iterator<? extends CommandNode<?>> it = geyserBrigadier.getChildren().iterator();
+
+                while (it.hasNext()) {
+                    CommandNode<?> subnode = it.next();
+                    GeyserCommand command = commands.get(subnode.getName());
+                    if (command != null) {
+                        if ((command.isBedrockOnly() && isJavaPlayer) || !player.hasPermission(command.getPermission())) {
+                            // Remove this from the node as we don't have permission to use it
+                            it.remove();
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * This early on, there is a rare chance that Geyser has yet to process the connection. We'll try to minimize that
+     * chance, though.
+     */
+    private boolean isProbablyJavaPlayer(Player player) {
+        if (GeyserImpl.getInstance().connectionByUuid(player.getUniqueId()) != null) {
+            // For sure this is a Bedrock player
+            return false;
+        }
+
+        if (GeyserImpl.getInstance().getConfig().isUseDirectConnection()) {
+            InetSocketAddress address = player.getAddress();
+            if (address != null) {
+                return address.getPort() != 0;
+            }
+        }
+        return true;
+    }
+}

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

@@ -26,6 +26,7 @@
 package org.geysermc.geyser.platform.spigot.command;
 
 import org.bukkit.Bukkit;
+import org.bukkit.Server;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandMap;
 import org.geysermc.geyser.GeyserImpl;
@@ -35,16 +36,24 @@ import java.lang.reflect.Field;
 
 public class GeyserSpigotCommandManager extends CommandManager {
 
-    private static CommandMap COMMAND_MAP;
+    private static final CommandMap COMMAND_MAP;
 
     static {
+        CommandMap commandMap = null;
         try {
-            Field cmdMapField = Bukkit.getServer().getClass().getDeclaredField("commandMap");
-            cmdMapField.setAccessible(true);
-            COMMAND_MAP = (CommandMap) cmdMapField.get(Bukkit.getServer());
-        } catch (NoSuchFieldException | IllegalAccessException ex) {
-            ex.printStackTrace();
+            // Paper-only
+            Server.class.getMethod("getCommandMap");
+            commandMap = Bukkit.getServer().getCommandMap();
+        } catch (NoSuchMethodException e) {
+            try {
+                Field cmdMapField = Bukkit.getServer().getClass().getDeclaredField("commandMap");
+                cmdMapField.setAccessible(true);
+                commandMap = (CommandMap) cmdMapField.get(Bukkit.getServer());
+            } catch (NoSuchFieldException | IllegalAccessException ex) {
+                ex.printStackTrace();
+            }
         }
+        COMMAND_MAP = commandMap;
     }
 
     public GeyserSpigotCommandManager(GeyserImpl geyser) {