import 'dart:convert';
import 'package:shared_preferences/shared_preferences.dart';
import '../features/settings/models/app_theme_preset.dart';
import '../models/home_config.dart';
import 'credentials_storage.dart';

/// Сервис для хранения списка "домов" и текущего выбранного.
/// Несекретные данные лежат в SharedPreferences, API-ключи -- отдельно.
class SettingsService {
  static const String _homesKey = 'ignis_homes';
  static const String _currentHomeKey = 'ignis_current_home_id';
  static const String _themeKey = 'ignis_theme_preset';

  final CredentialsStorage _credentialsStorage;

  SettingsService({CredentialsStorage? credentialsStorage})
    : _credentialsStorage = credentialsStorage ?? SecureCredentialsStorage();

  /// Загрузить все дома
  Future<List<HomeConfig>> getHomes() async {
    final prefs = await SharedPreferences.getInstance();
    final raw = prefs.getString(_homesKey);
    if (raw == null || raw.isEmpty) return [];
    final list = jsonDecode(raw) as List<dynamic>;
    final migrated = await _migrateApiKeysIfNeeded(prefs, list);
    return migrated.map(HomeConfig.fromJson).toList();
  }

  /// Сохранить весь список домов
  Future<void> saveHomes(List<HomeConfig> homes) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(
      _homesKey,
      jsonEncode(homes.map((h) => h.toJson()).toList()),
    );
  }

  /// Добавить или обновить дом
  Future<void> upsertHome(HomeConfig home, {String? apiKey}) async {
    final homes = await getHomes();
    final idx = homes.indexWhere((h) => h.id == home.id);
    if (idx >= 0) {
      homes[idx] = home;
    } else {
      homes.add(home);
    }
    if (apiKey != null) {
      await setHomeApiKey(home.id, apiKey);
    }
    await saveHomes(homes);
  }

  /// Удалить дом по id
  Future<void> deleteHome(String id) async {
    final homes = await getHomes();
    homes.removeWhere((h) => h.id == id);
    await saveHomes(homes);
    await deleteHomeApiKey(id);

    // Если удалили текущий -- сбрасываем выбор
    final currentId = await getCurrentHomeId();
    if (currentId == id) {
      await setCurrentHomeId(homes.isNotEmpty ? homes.first.id : null);
    }
  }

  /// Получить id текущего активного дома
  Future<String?> getCurrentHomeId() async {
    final prefs = await SharedPreferences.getInstance();
    return prefs.getString(_currentHomeKey);
  }

  /// Установить текущий дом
  Future<void> setCurrentHomeId(String? id) async {
    final prefs = await SharedPreferences.getInstance();
    if (id == null) {
      await prefs.remove(_currentHomeKey);
    } else {
      await prefs.setString(_currentHomeKey, id);
    }
  }

  /// Удобный метод: получить текущий HomeConfig или null
  Future<HomeConfig?> getCurrentHome() async {
    final homes = await getHomes();
    final id = await getCurrentHomeId();
    if (id == null && homes.isNotEmpty) return homes.first;
    try {
      return homes.firstWhere((h) => h.id == id);
    } catch (_) {
      return homes.isNotEmpty ? homes.first : null;
    }
  }

  Future<String?> getHomeApiKey(String homeId) =>
      _credentialsStorage.getApiKey(homeId);

  Future<String> requireHomeApiKey(String homeId) async {
    final key = await getHomeApiKey(homeId);
    if (key == null || key.isEmpty) {
      throw StateError('API key is missing for home $homeId');
    }
    return key;
  }

  Future<void> setHomeApiKey(String homeId, String apiKey) =>
      _credentialsStorage.setApiKey(homeId, apiKey);

  Future<void> deleteHomeApiKey(String homeId) =>
      _credentialsStorage.deleteApiKey(homeId);

  Future<AppThemePreset> getAppThemePreset() async {
    final prefs = await SharedPreferences.getInstance();
    return AppThemePreset.fromStorageValue(prefs.getString(_themeKey));
  }

  Future<void> setAppThemePreset(AppThemePreset preset) async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_themeKey, preset.storageValue);
  }

  Future<List<Map<String, dynamic>>> _migrateApiKeysIfNeeded(
    SharedPreferences prefs,
    List<dynamic> rawList,
  ) async {
    var changed = false;
    final result = <Map<String, dynamic>>[];

    for (final item in rawList) {
      final map = Map<String, dynamic>.from(item as Map);
      final id = map['id']?.toString();
      final legacyApiKey = map['apiKey']?.toString();

      if (id != null && legacyApiKey != null && legacyApiKey.isNotEmpty) {
        final existingKey = await getHomeApiKey(id);
        if (existingKey == null || existingKey.isEmpty) {
          await setHomeApiKey(id, legacyApiKey);
        }
      }

      if (map.remove('apiKey') != null) {
        changed = true;
      }
      result.add(map);
    }

    if (changed) {
      await prefs.setString(_homesKey, jsonEncode(result));
    }

    return result;
  }
}