feat: Add support for loading locales from plugin dir

src/main/java/com/onarandombox/MultiverseCore/MultiverseCore.java

@@ -164,6 +164,7 @@ public class MultiverseCore extends JavaPlugin implements MVCore {
         this.anchorManager.loadAnchors();
         this.registerEvents();
         this.registerCommands();
+        this.setUpLocales();
         this.registerDestinations();
         this.setupMetrics();
         this.saveMVConfig();
@@ -215,6 +216,14 @@ public class MultiverseCore extends JavaPlugin implements MVCore {
         this.commandManager.registerCommand(new UnloadCommand(this));
     }
 
+    /**
+     * Resgister locales
+     */
+    private void setUpLocales() {
+        this.commandManager.getLocales().addFileResClassLoader(this);
+        this.commandManager.getLocales().addMessageBundles("multiverse-core");
+    }
+
     /**
      * Register all the destinations.
      */

src/main/java/com/onarandombox/MultiverseCore/commandtools/MVCommandManager.java

@@ -1,7 +1,5 @@
 package com.onarandombox.MultiverseCore.commandtools;
 
-import java.util.Locale;
-
 import co.aikar.commands.BukkitCommandCompletionContext;
 import co.aikar.commands.BukkitCommandExecutionContext;
 import co.aikar.commands.CommandCompletions;
@@ -10,6 +8,7 @@ import co.aikar.commands.PaperCommandManager;
 import com.onarandombox.MultiverseCore.MultiverseCore;
 import com.onarandombox.MultiverseCore.commandtools.flags.CommandFlagsManager;
 import com.onarandombox.MultiverseCore.commandtools.queue.CommandQueueManager;
+import com.onarandombox.MultiverseCore.locale.PluginLocales;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -20,6 +19,7 @@ public class MVCommandManager extends PaperCommandManager {
     private final MultiverseCore plugin;
     private CommandFlagsManager flagsManager;
     private CommandQueueManager commandQueueManager;
+    private PluginLocales pluginLocales;
 
     public MVCommandManager(@NotNull MultiverseCore plugin) {
         super(plugin);
@@ -27,11 +27,6 @@ public class MVCommandManager extends PaperCommandManager {
 
         // Setup conditions
         MVCommandConditions.load(this, plugin);
-
-        // Setup locale
-        this.addSupportedLanguage(Locale.ENGLISH);
-        this.locales.addMessageBundles("multiverse-core");
-        this.locales.loadLanguages();
     }
 
     /**
@@ -46,6 +41,16 @@ public class MVCommandManager extends PaperCommandManager {
         return flagsManager;
     }
 
+    @Override
+    public PluginLocales getLocales() {
+        if (this.pluginLocales == null) {
+            this.pluginLocales = new PluginLocales(this);
+            this.locales = pluginLocales; // For parent class
+            this.pluginLocales.loadLanguages();
+        }
+        return this.pluginLocales;
+    }
+
     /**
      * Manager for command that requires /mv confirm before execution.
      *

src/main/java/com/onarandombox/MultiverseCore/locale/FileResClassLoader.java

@@ -0,0 +1,46 @@
+package com.onarandombox.MultiverseCore.locale;
+
+import org.bukkit.plugin.Plugin;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+
+/**
+ * A class loader that loads resources from the plugin's locales folder.
+ */
+public class FileResClassLoader extends ClassLoader {
+    private final transient File localesFolder;
+
+    public FileResClassLoader(final ClassLoader classLoader, final Plugin plugin) {
+        super(classLoader);
+        this.localesFolder = new File(plugin.getDataFolder(), "locales");
+    }
+
+    @Override
+    public URL getResource(final String string) {
+        final File file = new File(localesFolder, string);
+        if (file.exists()) {
+            try {
+                return file.toURI().toURL();
+            } catch (final MalformedURLException ignored) {
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public InputStream getResourceAsStream(final String string) {
+        final File file = new File(localesFolder, string);
+        if (file.exists()) {
+            try {
+                return new FileInputStream(file);
+            } catch (final FileNotFoundException ignored) {
+            }
+        }
+        return null;
+    }
+}

src/main/java/com/onarandombox/MultiverseCore/locale/PluginLocales.java

@@ -0,0 +1,15 @@
+package com.onarandombox.MultiverseCore.locale;
+
+import co.aikar.commands.BukkitCommandManager;
+import co.aikar.commands.BukkitLocales;
+import org.bukkit.plugin.Plugin;
+
+public class PluginLocales extends BukkitLocales {
+    public PluginLocales(BukkitCommandManager manager) {
+        super(manager);
+    }
+
+    public boolean addFileResClassLoader(Plugin plugin) {
+        return this.addBundleClassLoader(new FileResClassLoader(plugin.getClass().getClassLoader(), plugin));
+    }
+}