Added automatic update-merge of settings for new settings instead of falling back to defaults

lib/storage/base/settingsProvider.dart

@@ -25,19 +25,31 @@ class SettingsProvider extends ChangeNotifier {
   }
 
   SettingsProvider() {
-    init();
+    _readFromStorage();
   }
 
-  void init({bool resetConfig = false}) async {
+  void reset() async {
     _storage = await SharedPreferences.getInstance();
+    _storage.remove(_fieldName);
 
-    if(resetConfig) _storage.remove(_fieldName);
+    notifyListeners();
+  }
+
+  void _readFromStorage() async {
+    _storage = await SharedPreferences.getInstance();
 
     try {
       _settings = Settings.fromJson(jsonDecode(_storage.getString(_fieldName)!));
-    } catch(e) {
-      log("Settings are defective, using defaults: ${e.toString()}");
-      _settings = _defaults();
+    } catch(exception) {
+      try {
+        log("Settings were changed, trying to recover from old Settings: ${exception.toString()}");
+        _settings = Settings.fromJson(_mergeSettings(jsonDecode(_storage.getString(_fieldName)!), _defaults().toJson()));
+        log("Settings recovered successfully: ${_settings.toJson().toString()}");
+      } catch(exception) {
+        log("Settings are defective and not recoverable, using defaults: ${exception.toString()}");
+        _settings = _defaults();
+        log("Settings were reset to defaults!");
+      }
     }
 
     notifyListeners();
@@ -47,6 +59,22 @@ class SettingsProvider extends ChangeNotifier {
     await _storage.setString(_fieldName, jsonEncode(_settings.toJson()));
   }
 
+  Map<String, dynamic> _mergeSettings(Map<String, dynamic> oldMap, Map<String, dynamic> newMap) {
+    Map<String, dynamic> mergedMap = Map.from(newMap);
+
+    oldMap.forEach((key, value) {
+      if (mergedMap.containsKey(key)) {
+        if (value is Map<String, dynamic> && mergedMap[key] is Map<String, dynamic>) {
+          mergedMap[key] = _mergeSettings(value, mergedMap[key]);
+        } else {
+          mergedMap[key] = value;
+        }
+      }
+    });
+
+    return mergedMap;
+  }
+
   Settings _defaults() {
     return Settings(
       appTheme: ThemeMode.system,