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

class ThemeNotifier extends Notifier<ThemeMode> {
  static const _themePrefKey = 'theme_pref';

  @override
  ThemeMode build() {
    _loadTheme();
    return ThemeMode.system;
  }

  Future<void> _loadTheme() async {
    final prefs = await SharedPreferences.getInstance();
    final themeString = prefs.getString(_themePrefKey);
    if (themeString != null) {
      if (themeString == 'light') {
        state = ThemeMode.light;
      } else if (themeString == 'dark') {
        state = ThemeMode.dark;
      }
    }
  }

  Future<void> setTheme(ThemeMode mode) async {
    state = mode;
    final prefs = await SharedPreferences.getInstance();
    if (mode == ThemeMode.light) {
      await prefs.setString(_themePrefKey, 'light');
    } else if (mode == ThemeMode.dark) {
      await prefs.setString(_themePrefKey, 'dark');
    } else {
      await prefs.setString(_themePrefKey, 'system');
    }
  }
}

final themeProvider = NotifierProvider<ThemeNotifier, ThemeMode>(() {
  return ThemeNotifier();
});