import 'package:flutter_dotenv/flutter_dotenv.dart';
import 'package:firebase_core/firebase_core.dart';
import '../config/config_loader.dart';
import '../data/local/local_storage_service.dart';
import '../data/nostr/nostr_service.dart';
import '../data/sync/sync_engine.dart';
import '../data/firebase/firebase_service.dart';
import '../data/session/session_service.dart';
import '../data/immich/immich_service.dart';
import 'app_services.dart';
import 'service_locator.dart';
import 'logger.dart';

/// Initializes all application services.
/// 
/// Handles the complete initialization sequence:
/// 1. Load environment configuration
/// 2. Initialize Firebase (if enabled)
/// 3. Initialize local storage
/// 4. Initialize Nostr service and sync engine
/// 5. Initialize Immich service
/// 6. Initialize Firebase service (if enabled)
/// 7. Initialize session service
/// 8. Register all services with ServiceLocator
class AppInitializer {
  /// Initializes all application services.
  /// 
  /// [environment] - The environment to use ('dev' or 'prod').
  /// 
  /// Returns an [AppServices] instance with all initialized services.
  /// 
  /// Throws if initialization fails.
  static Future<AppServices> initialize({
    String environment = 'dev',
  }) async {
    Logger.info('Starting application initialization...');

    // Load .env file (optional - falls back to defaults if not found)
    try {
      await dotenv.load(fileName: '.env');
      Logger.debug('.env file loaded successfully');
    } catch (e) {
      Logger.warning('.env file not found, using default values: $e');
    }

    // Load configuration based on environment
    final config = ConfigLoader.load(environment);
    Logger.setEnabled(config.enableLogging);
    Logger.info('Configuration loaded for environment: $environment');

    // Initialize Firebase if enabled
    if (config.firebaseConfig.enabled) {
      try {
        await Firebase.initializeApp();
        Logger.info('Firebase initialized successfully');
      } catch (e) {
        Logger.error(
          'Firebase initialization failed: $e',
          e,
        );
        Logger.warning(
          'Note: Firebase requires google-services.json (Android) and GoogleService-Info.plist (iOS)',
        );
      }
    }

    // Initialize local storage service
    Logger.debug('Initializing local storage service...');
    final storageService = LocalStorageService();
    try {
      await storageService.initialize();
      Logger.info('Local storage service initialized');
    } catch (e) {
      Logger.error('Failed to initialize storage: $e', e);
      rethrow;
    }

    // Initialize Nostr service and sync engine
    Logger.debug('Initializing Nostr service...');
    final nostrService = NostrService();
    final nostrKeyPair = nostrService.generateKeyPair();
    
    final syncEngine = SyncEngine(
      localStorage: storageService,
      nostrService: nostrService,
      nostrKeyPair: nostrKeyPair,
    );
    Logger.info('Nostr service and sync engine initialized');

    // Load relays from config
    for (final relayUrl in config.nostrRelays) {
      nostrService.addRelay(relayUrl);
    }
    Logger.debug('Loaded ${config.nostrRelays.length} relay(s) from config');

    // Initialize Immich service
    Logger.debug('Initializing Immich service...');
    final immichService = ImmichService(
      baseUrl: config.immichBaseUrl,
      apiKey: config.immichApiKey,
      localStorage: storageService,
    );
    Logger.info('Immich service initialized');

    // Initialize Firebase service if enabled
    FirebaseService? firebaseService;
    if (config.firebaseConfig.enabled) {
      try {
        Logger.debug('Initializing Firebase service...');
        firebaseService = FirebaseService(
          config: config.firebaseConfig,
          localStorage: storageService,
        );
        await firebaseService.initialize();
        Logger.info('Firebase service initialized: ${firebaseService.isEnabled}');
      } catch (e) {
        Logger.error('Firebase service initialization failed: $e', e);
        firebaseService = null;
      }
    }

    // Initialize SessionService with Firebase and Nostr integration
    Logger.debug('Initializing session service...');
    final sessionService = SessionService(
      localStorage: storageService,
      syncEngine: syncEngine,
      firebaseService: firebaseService,
      nostrService: nostrService,
    );
    Logger.info('Session service initialized');

    // Create AppServices container
    final appServices = AppServices(
      localStorageService: storageService,
      nostrService: nostrService,
      syncEngine: syncEngine,
      firebaseService: firebaseService,
      sessionService: sessionService,
      immichService: immichService,
    );

    // Register all services with ServiceLocator
    ServiceLocator.instance.registerServices(
      localStorageService: storageService,
      nostrService: nostrService,
      syncEngine: syncEngine,
      firebaseService: firebaseService,
      sessionService: sessionService,
      immichService: immichService,
    );

    Logger.info('Application initialization completed successfully');
    return appServices;
  }
}