Refactor: Introduce LocaleController and ScaleController, unify text and language settings, and simplify AppSettingsView structure.

finlog_app/app/lib/core/ui/controller/locale_controller.dart

@@ -2,8 +2,6 @@ import 'package:flutter/material.dart';
 import 'package:fluttery/fluttery.dart';
 import 'package:fluttery/preferences.dart';
 
-/// Controls the current app language (system, de, en, ...).
-/// Loads the locale from Preferences or falls back to system default.
 class LocaleController extends ChangeNotifier {
   final Preferences _prefs;
 
@@ -11,32 +9,36 @@ class LocaleController extends ChangeNotifier {
 
   static const _key = 'language';
 
-  String _current = 'system';
+  LanguagePref _current = LanguagePref.en; // Default = Englisch
 
   Future<void> init() async {
     final saved = await _prefs.getString(_key);
-    _current = saved ?? 'system';
+    _current = switch (saved) {
+      'de' => LanguagePref.de,
+      'system' => LanguagePref.system,
+      'en' || _ => LanguagePref.en, // default fallback = en
+    };
     notifyListeners();
   }
 
-  void setLanguage(String lang) {
-    _current = lang;
+  void setLanguage(LanguagePref pref) {
+    if (_current == pref) return;
+    _current = pref;
     notifyListeners();
-    _prefs.setString(_key, lang);
+    _prefs.setString(_key, pref.name); // fire-and-forget
   }
 
-  /// Returns the actual Locale or null = system.
-  Locale? get locale {
-    switch (_current) {
-      case 'de':
-        return const Locale('de');
-      case 'en':
-        return const Locale('en');
-      case 'system':
-      default:
-        return null;
-    }
-  }
+  LanguagePref get language => _current;
 
-  String get language => _current;
+  Locale? get locale => _current.locale;
+}
+
+enum LanguagePref {
+  system(null), // folgt System
+  de(Locale('de')), // Deutsch
+  en(Locale('en')); // Englisch (default)
+
+  final Locale? locale;
+
+  const LanguagePref(this.locale);
 }

finlog_app/app/lib/core/ui/controller/scale_controller.dart

@@ -2,8 +2,6 @@ import 'package:flutter/material.dart';
 import 'package:fluttery/fluttery.dart';
 import 'package:fluttery/preferences.dart';
 
-/// Controls the current text scale (system, small, medium, large).
-/// Loads the value from Preferences or falls back to system default.
 class ScaleController extends ChangeNotifier {
   final Preferences _prefs;
 
@@ -11,37 +9,40 @@ class ScaleController extends ChangeNotifier {
 
   static const _key = 'textScale';
 
-  /// supported sizes
-  static const Map<String, double> _factors = {
-    'system': 1.0,
-    'small': 0.9,
-    'medium': 1.1,
-    'large': 1.25,
-  };
+  TextScalePref _current = TextScalePref.system;
 
-  String _current = 'system';
+  /// Faktor direkt vom Enum
+  double get factor => _current.factor;
 
-  /// Loads text scale from Preferences.
   Future<void> init() async {
     final saved = await _prefs.getString(_key);
-    _current = saved ?? 'system';
-    if (!_factors.containsKey(_current)) {
-      _current = 'system';
-    }
+    _current = switch (saved) {
+      'small' => TextScalePref.small,
+      'medium' => TextScalePref.medium,
+      'large' => TextScalePref.large,
+      _ => TextScalePref.system,
+    };
     notifyListeners();
   }
 
   /// Set text scale and persist.
-  void setScale(String scale) {
-    if (!_factors.containsKey(scale)) return;
-    _current = scale;
+  void setScale(TextScalePref pref) {
+    if (_current == pref) return;
+    _current = pref;
     notifyListeners();
-    _prefs.setString(_key, scale);
+    _prefs.setString(_key, pref.name); // fire-and-forget
   }
 
-  /// get current factor (e.g. for MediaQuery.textScaler)
-  double get factor => _factors[_current]!;
-
-  /// get current string (system/small/medium/large)
-  String get scale => _current;
+  TextScalePref get scale => _current;
+}
+
+enum TextScalePref {
+  system(1.0),
+  small(0.9),
+  medium(1.1),
+  large(1.4);
+
+  final double factor;
+
+  const TextScalePref(this.factor);
 }