more refactor

lib/settings/preferences_repository.dart

@@ -0,0 +1,34 @@
+import 'dart:async';
+
+import 'package:shared_preferences/shared_preferences.dart';
+
+import '../tools/tools.dart';
+import 'models/models.dart';
+
+class PreferencesRepository {
+  PreferencesRepository._();
+
+  late final SharedPreferencesValue<Preferences> _data;
+
+  Preferences get value => _data.requireValue;
+  Stream<Preferences> get stream => _data.stream;
+
+  //////////////////////////////////////////////////////////////
+  /// Singleton initialization
+
+  static PreferencesRepository instance = PreferencesRepository._();
+
+  Future<void> init() async {
+    final sharedPreferences = await SharedPreferences.getInstance();
+    _data = SharedPreferencesValue<Preferences>(
+        sharedPreferences: sharedPreferences,
+        keyName: 'preferences',
+        valueFromJson: (obj) =>
+            obj != null ? Preferences.fromJson(obj) : Preferences.defaults,
+        valueToJson: (val) => val.toJson());
+    await _data.get();
+  }
+
+  Future<void> set(Preferences value) => _data.set(value);
+  Future<Preferences> get() => _data.get();
+}