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

part 'theme_provider.g.dart';

/// Key for storing theme preference in SharedPreferences
const String _themeModeKey = 'theme_mode';

/// Provider for theme mode state management
@riverpod
class ThemeNotifier extends _$ThemeNotifier {
  @override
  ThemeMode build() {
    _loadThemeMode();
    return ThemeMode.system; // Default value until loaded
  }

  /// Load theme mode from SharedPreferences
  Future<void> _loadThemeMode() async {
    final prefs = await SharedPreferences.getInstance();
    final themeModeString = prefs.getString(_themeModeKey);

    if (themeModeString != null) {
      final themeMode = ThemeMode.values.firstWhere(
        (mode) => mode.name == themeModeString,
        orElse: () => ThemeMode.system,
      );
      state = themeMode;
    }
  }

  /// Set theme mode and persist to SharedPreferences
  Future<void> setThemeMode(ThemeMode mode) async {
    state = mode;
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_themeModeKey, mode.name);
  }
}