Introduce CommandSender.getLocale() (#1431)

* Introduce CommandSender.getLocale()

This allows Geyser-specific commands (e.g. `/geyser help`) to be displayed in the (Java or Bedrock) player's default language, which stops those commands from simply being displayed in the default locale.

* Tweak Javadoc

* Set CommandManager's GeyserConnector to final

* Clean up

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

@@ -40,6 +40,7 @@ import org.geysermc.connector.utils.FileUtils;
 import org.geysermc.connector.utils.LanguageUtils;
 import org.geysermc.platform.spigot.command.GeyserSpigotCommandExecutor;
 import org.geysermc.platform.spigot.command.GeyserSpigotCommandManager;
+import org.geysermc.platform.spigot.command.SpigotCommandSender;
 import org.geysermc.platform.spigot.world.GeyserSpigotBlockPlaceListener;
 import org.geysermc.platform.spigot.world.GeyserSpigotWorldManager;
 
@@ -130,6 +131,9 @@ public class GeyserSpigotPlugin extends JavaPlugin implements GeyserBootstrap {
             geyserLogger.debug("Legacy version of Minecraft (1.15.2 or older) detected; not using 3D biomes.");
         }
 
+        // Set if we need to use a different method for getting a player's locale
+        SpigotCommandSender.setUseLegacyLocaleMethod(!isCompatible(Bukkit.getServer().getVersion(), "1.12.0"));
+
         this.geyserWorldManager = new GeyserSpigotWorldManager(isLegacy, use3dBiomes, isViaVersion);
         GeyserSpigotBlockPlaceListener blockPlaceListener = new GeyserSpigotBlockPlaceListener(connector, isLegacy, isViaVersion);
 

bootstrap/spigot/src/main/java/org/geysermc/platform/spigot/command/GeyserSpigotCommandExecutor.java

@@ -32,7 +32,6 @@ import org.bukkit.command.CommandSender;
 import org.bukkit.command.TabExecutor;
 import org.geysermc.connector.GeyserConnector;
 import org.geysermc.connector.command.GeyserCommand;
-import org.geysermc.connector.network.session.GeyserSession;
 import org.geysermc.connector.utils.LanguageUtils;
 
 import java.util.ArrayList;
@@ -42,21 +41,17 @@ import java.util.List;
 @AllArgsConstructor
 public class GeyserSpigotCommandExecutor implements TabExecutor {
 
-    private GeyserConnector connector;
+    private final GeyserConnector connector;
 
     @Override
     public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
         if (args.length > 0) {
             if (getCommand(args[0]) != null) {
                 if (!sender.hasPermission(getCommand(args[0]).getPermission())) {
-                    String message = "";
-                    if (sender instanceof GeyserSession) {
-                        message = LanguageUtils.getPlayerLocaleString("geyser.bootstrap.command.permission_fail", ((GeyserSession) sender).getClientData().getLanguageCode());
-                    } else {
-                        message = LanguageUtils.getLocaleStringLog("geyser.bootstrap.command.permission_fail");
-                    }
+                    SpigotCommandSender commandSender = new SpigotCommandSender(sender);
+                    String message = LanguageUtils.getPlayerLocaleString("geyser.bootstrap.command.permission_fail", commandSender.getLocale());;
 
-                    sender.sendMessage(ChatColor.RED + message);
+                    commandSender.sendMessage(ChatColor.RED + message);
                     return true;
                 }
                 getCommand(args[0]).execute(new SpigotCommandSender(sender), args.length > 1 ? Arrays.copyOfRange(args, 1, args.length) : new String[0]);

bootstrap/spigot/src/main/java/org/geysermc/platform/spigot/command/SpigotCommandSender.java

@@ -25,15 +25,33 @@
 
 package org.geysermc.platform.spigot.command;
 
-import lombok.AllArgsConstructor;
-
 import org.bukkit.command.ConsoleCommandSender;
+import org.bukkit.entity.Player;
+import org.geysermc.connector.GeyserConnector;
 import org.geysermc.connector.command.CommandSender;
+import org.geysermc.connector.utils.LanguageUtils;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 
-@AllArgsConstructor
 public class SpigotCommandSender implements CommandSender {
 
-    private org.bukkit.command.CommandSender handle;
+    /**
+     * Whether to use {@code Player.getLocale()} or {@code Player.spigot().getLocale()}, depending on version.
+     * 1.12 or greater should not use the legacy method.
+     */
+    private static boolean USE_LEGACY_METHOD = false;
+    private static Method LOCALE_METHOD;
+
+    private final org.bukkit.command.CommandSender handle;
+    private final String locale;
+
+    public SpigotCommandSender(org.bukkit.command.CommandSender handle) {
+        this.handle = handle;
+        this.locale = getSpigotLocale();
+        // Ensure even Java players' languages are loaded
+        LanguageUtils.loadGeyserLocale(locale);
+    }
 
     @Override
     public String getName() {
@@ -49,4 +67,49 @@ public class SpigotCommandSender implements CommandSender {
     public boolean isConsole() {
         return handle instanceof ConsoleCommandSender;
     }
+
+    @Override
+    public String getLocale() {
+        return locale;
+    }
+
+    /**
+     * Set if we are on pre-1.12, and therefore {@code player.getLocale()} doesn't exist and we have to get
+     * {@code player.spigot().getLocale()}.
+     *
+     * @param useLegacyMethod if we are running pre-1.12 and therefore need to use reflection to get the player locale
+     */
+    public static void setUseLegacyLocaleMethod(boolean useLegacyMethod) {
+        USE_LEGACY_METHOD = useLegacyMethod;
+        if (USE_LEGACY_METHOD) {
+            try {
+                //noinspection JavaReflectionMemberAccess - of course it doesn't exist; that's why we're doing it
+                LOCALE_METHOD = Player.Spigot.class.getMethod("getLocale");
+            } catch (NoSuchMethodException e) {
+                GeyserConnector.getInstance().getLogger().debug("Player.Spigot.getLocale() doesn't exist? Not a big deal but if you're seeing this please report it to the developers!");
+            }
+        }
+    }
+
+    /**
+     * So we only have to do nasty reflection stuff once per command
+     *
+     * @return the locale of the Spigot player
+     */
+    private String getSpigotLocale() {
+        if (handle instanceof Player) {
+            Player player = (Player) handle;
+            if (USE_LEGACY_METHOD) {
+                try {
+                    // sigh
+                    // This was the only option on older Spigot instances and now it's gone
+                    return (String) LOCALE_METHOD.invoke(player.spigot());
+                } catch (IllegalAccessException | InvocationTargetException ignored) {
+                }
+            } else {
+                return player.getLocale();
+            }
+        }
+        return LanguageUtils.getDefaultLocale();
+    }
 }