import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';

class ThemeProvider extends ChangeNotifier {
  final SharedPreferences _prefs;
  static const String _themeKey = 'theme_mode';

  ThemeMode _themeMode = ThemeMode.system;
  ThemeMode get themeMode => _themeMode;

  ThemeProvider(this._prefs) {
    _loadTheme();
  }

  void _loadTheme() {
    final themeString = _prefs.getString(_themeKey);
    switch (themeString) {
      case 'light':
        _themeMode = ThemeMode.light;
        break;
      case 'dark':
        _themeMode = ThemeMode.dark;
        break;
      default:
        _themeMode = ThemeMode.system;
        break;
    }
  }

  Future<void> setThemeMode(ThemeMode mode) async {
    if (mode == _themeMode) return;
    _themeMode = mode;
    notifyListeners();

    String themeString;
    switch (mode) {
      case ThemeMode.light:
        themeString = 'light';
        break;
      case ThemeMode.dark:
        themeString = 'dark';
        break;
      case ThemeMode.system:
      default:
        themeString = 'system';
        break;
    }
    await _prefs.setString(_themeKey, themeString);
  }
}