Simplify the language fallback system

src/main/java/emu/grasscutter/Config.java

@@ -23,7 +23,7 @@ public final class Config {
 	public GameServerOptions GameServer = new GameServerOptions();
 	public DispatchServerOptions DispatchServer = new DispatchServerOptions();
 	public Locale LocaleLanguage = Locale.getDefault();
-	public Locale DefaultLanguage = Locale.US;
+	public Locale DefaultLanguage = Locale.ENGLISH;
 
 	public Boolean OpenStamina = true;
 	public GameServerOptions getGameServerOptions() {

src/main/java/emu/grasscutter/Grasscutter.java

@@ -149,9 +149,10 @@ public final class Grasscutter {
 
 	public static void loadLanguage() {
 		var locale = config.LocaleLanguage;
-		String languageTag = locale.toLanguageTag();
+		var languageTag = locale.toLanguageTag();
+		
 		if (languageTag.equals("und")) {
-			Grasscutter.getLogger().error("Illegal locale language, using en-US instead.");
+			Grasscutter.getLogger().error("Illegal locale language, using 'en-US' instead.");
 			language = Language.getLanguage("en-US");
 		} else {
 			language = Language.getLanguage(languageTag);

src/main/java/emu/grasscutter/utils/Language.java

@@ -19,7 +19,7 @@ public final class Language {
      * @return A language instance.
      */
     public static Language getLanguage(String langCode) {
-        return new Language(langCode + ".json");
+        return new Language(langCode + ".json", Grasscutter.getConfig().DefaultLanguage.toLanguageTag());
     }
 
     /**
@@ -30,6 +30,7 @@ public final class Language {
      */
     public static String translate(String key, Object... args) {
         String translated = Grasscutter.getLanguage().get(key);
+        
         try {
             return translated.formatted(args);
         } catch (Exception exception) {
@@ -38,48 +39,25 @@ public final class Language {
         }
     }
 
-    /**
-     * creates a language instance.
-     * @param fileName The name of the language file.
-     */
-    private Language(String fileName) {
-        @Nullable JsonObject languageData = null;
-
-        languageData = loadLanguage(fileName);
-
-        if (languageData == null) {
-            Grasscutter.getLogger().info("Now switch to default language");
-            languageData = loadDefaultLanguage();
-        }
-
-        assert languageData != null : "languageData is null";
-        this.languageData = languageData;
-    }
-
-    /**
-     * Load default language file and creates a language instance.
-     * @return language data
-     */
-    private JsonObject loadDefaultLanguage() {
-        var fileName = Grasscutter.getConfig().DefaultLanguage.toLanguageTag() + ".json";
-        return loadLanguage(fileName);
-    }
-
     /**
      * Reads a file and creates a language instance.
      * @param fileName The name of the language file.
-     * @return language data
      */
-    private JsonObject loadLanguage(String fileName) {
+    private Language(String fileName, String fallback) {
         @Nullable JsonObject languageData = null;
 
         try {
             InputStream file = Grasscutter.class.getResourceAsStream("/languages/" + fileName);
+            if(file == null) {
+                file = Grasscutter.class.getResourceAsStream("/languages/" + fallback);
+            }
+            
             languageData = Grasscutter.getGsonFactory().fromJson(Utils.readFromInputStream(file), JsonObject.class);
         } catch (Exception exception) {
-            Grasscutter.getLogger().warn("Failed to load language file: " + fileName);
+            Grasscutter.getLogger().warn("Failed to load language file: " + fileName, exception);
         }
-        return languageData;
+        
+        this.languageData = languageData;
     }
 
     /**

src/main/java/emu/grasscutter/utils/Utils.java

@@ -1,6 +1,7 @@
 package emu.grasscutter.utils;
 
 import java.io.*;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
 import java.time.*;
@@ -254,7 +255,7 @@ public final class Utils {
 	 */
 	public static String readFromInputStream(InputStream stream) {
 		StringBuilder stringBuilder = new StringBuilder();
-		try (BufferedReader reader = new BufferedReader(new InputStreamReader(stream,"UTF-8"))) {
+		try (BufferedReader reader = new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8))) {
 			String line; while ((line = reader.readLine()) != null) {
 				stringBuilder.append(line);
 			} stream.close();