feat: everything up to bluetooth scanning

lib/util/sharedPrefs.dart

@@ -0,0 +1,73 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+part 'sharedPrefs.g.dart';
+
+final sharedPreferencesProvider =
+    Provider<SharedPreferences>((ref) => throw UnimplementedError());
+
+class SharedPrefNotifier<T> extends StateNotifier<T> {
+  final SharedPreferences prefs;
+  final String key;
+  final T defaultValue;
+
+  SharedPrefNotifier({
+    required this.prefs,
+    required this.key,
+    required this.defaultValue,
+  }) : super(prefs.containsKey(key)
+            ? _getValue<T>(prefs, key, defaultValue)
+            : defaultValue);
+
+  // Helper to get the value with proper typing
+  static T _getValue<T>(SharedPreferences prefs, String key, T defaultValue) {
+    switch (T) {
+      case String:
+        return prefs.getString(key) as T ?? defaultValue;
+      case bool:
+        return prefs.getBool(key) as T ?? defaultValue;
+      case int:
+        return prefs.getInt(key) as T ?? defaultValue;
+      case double:
+        return prefs.getDouble(key) as T ?? defaultValue;
+      case const (List<String>):
+        return prefs.getStringList(key) as T ?? defaultValue;
+      default:
+        throw UnsupportedError('Type $T not supported by SharedPreferences');
+    }
+  }
+
+  Future<void> update(T value) async {
+    switch (T) {
+      case String:
+        await prefs.setString(key, value as String);
+        break;
+      case bool:
+        await prefs.setBool(key, value as bool);
+        break;
+      case int:
+        await prefs.setInt(key, value as int);
+        break;
+      case double:
+        await prefs.setDouble(key, value as double);
+        break;
+      case const (List<String>):
+        await prefs.setStringList(key, value as List<String>);
+        break;
+      default:
+        throw UnsupportedError('Type $T not supported by SharedPreferences');
+    }
+    state = value;
+  }
+}
+
+final isDarkModeProvider =
+    StateNotifierProvider<SharedPrefNotifier<bool>, bool>((ref) {
+  final prefs = ref.watch(sharedPreferencesProvider);
+  return SharedPrefNotifier<bool>(
+    prefs: prefs,
+    key: 'is_dark_mode',
+    defaultValue: false,
+  );
+});