import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:shared_preferences/shared_preferences.dart';

const _kKey = 'app_theme';
const _kValid = {'a', 'b', 'c'};

class ThemeController extends StateNotifier<String> {
  ThemeController() : super('a');

  Future<void> restore() async {
    final prefs = await SharedPreferences.getInstance();
    final v = prefs.getString(_kKey);
    if (v != null && _kValid.contains(v)) state = v;
  }

  Future<void> set(String key) async {
    if (!_kValid.contains(key)) return;
    state = key;
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_kKey, key);
  }
}

final themeControllerProvider =
    StateNotifierProvider<ThemeController, String>((ref) => ThemeController());