import 'dart:async';
import 'dart:ui';

import 'package:background_downloader/background_downloader.dart';
import 'package:flutter/material.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:immich_mobile/constants/constants.dart';
import 'package:immich_mobile/domain/utils/isolate_lock_manager.dart';
import 'package:immich_mobile/infrastructure/repositories/db.repository.dart';
import 'package:immich_mobile/infrastructure/repositories/logger_db.repository.dart';
import 'package:immich_mobile/platform/background_worker_api.g.dart';
import 'package:immich_mobile/providers/app_settings.provider.dart';
import 'package:immich_mobile/providers/background_sync.provider.dart';
import 'package:immich_mobile/providers/backup/drift_backup.provider.dart';
import 'package:immich_mobile/providers/db.provider.dart';
import 'package:immich_mobile/providers/infrastructure/db.provider.dart';
import 'package:immich_mobile/providers/user.provider.dart';
import 'package:immich_mobile/repositories/file_media.repository.dart';
import 'package:immich_mobile/services/app_settings.service.dart';
import 'package:immich_mobile/services/auth.service.dart';
import 'package:immich_mobile/services/localization.service.dart';
import 'package:immich_mobile/services/upload.service.dart';
import 'package:immich_mobile/utils/bootstrap.dart';
import 'package:immich_mobile/utils/http_ssl_options.dart';
import 'package:isar/isar.dart';
import 'package:logging/logging.dart';

class BackgroundWorkerFgService {
  final BackgroundWorkerFgHostApi _foregroundHostApi;

  const BackgroundWorkerFgService(this._foregroundHostApi);

  // TODO: Move this call to native side once old timeline is removed
  Future<void> enable() => _foregroundHostApi.enable();

  Future<void> disable() => _foregroundHostApi.disable();
}

class BackgroundWorkerBgService extends BackgroundWorkerFlutterApi {
  late final ProviderContainer _ref;
  final Isar _isar;
  final Drift _drift;
  final DriftLogger _driftLogger;
  final BackgroundWorkerBgHostApi _backgroundHostApi;
  final Logger _logger = Logger('BackgroundUploadBgService');
  late final IsolateLockManager _lockManager;

  bool _isCleanedUp = false;

  BackgroundWorkerBgService({required Isar isar, required Drift drift, required DriftLogger driftLogger})
    : _isar = isar,
      _drift = drift,
      _driftLogger = driftLogger,
      _backgroundHostApi = BackgroundWorkerBgHostApi() {
    _ref = ProviderContainer(
      overrides: [
        dbProvider.overrideWithValue(isar),
        isarProvider.overrideWithValue(isar),
        driftProvider.overrideWith(driftOverride(drift)),
      ],
    );
    _lockManager = IsolateLockManager(onCloseRequest: _cleanup);
    BackgroundWorkerFlutterApi.setUp(this);
  }

  bool get _isBackupEnabled => _ref.read(appSettingsServiceProvider).getSetting(AppSettingsEnum.enableBackup);

  Future<void> init() async {
    try {
      await loadTranslations();
      HttpSSLOptions.apply(applyNative: false);
      await _ref.read(authServiceProvider).setOpenApiServiceEndpoint();

      // Initialize the file downloader
      await FileDownloader().configure(
        globalConfig: [
          // maxConcurrent: 6, maxConcurrentByHost(server):6, maxConcurrentByGroup: 3
          (Config.holdingQueue, (6, 6, 3)),
          // On Android, if files are larger than 256MB, run in foreground service
          (Config.runInForegroundIfFileLargerThan, 256),
        ],
      );
      await FileDownloader().trackTasksInGroup(kDownloadGroupLivePhoto, markDownloadedComplete: false);
      await FileDownloader().trackTasks();
      configureFileDownloaderNotifications();
      await _ref.read(fileMediaRepositoryProvider).enableBackgroundAccess();

      // Notify the host that the background upload service has been initialized and is ready to use
      debugPrint("Acquiring background worker lock");
      if (await _lockManager.acquireLock().timeout(
        const Duration(seconds: 5),
        onTimeout: () {
          _lockManager.cancel();
          return false;
        },
      )) {
        _logger.info("Acquired background worker lock");
        await _backgroundHostApi.onInitialized();
        return;
      }

      _logger.warning("Failed to acquire background worker lock");
      await _cleanup();
      await _backgroundHostApi.close();
    } catch (error, stack) {
      _logger.severe("Failed to initialize background worker", error, stack);
      _backgroundHostApi.close();
    }
  }

  @override
  Future<void> onAndroidUpload() async {
    try {
      _logger.info('Android background processing started');
      final sw = Stopwatch()..start();

      await _syncAssets(hashTimeout: Duration(minutes: _isBackupEnabled ? 3 : 6));
      await _handleBackup(processBulk: false);

      sw.stop();
      _logger.info("Android background processing completed in ${sw.elapsed.inSeconds}s");
    } catch (error, stack) {
      _logger.severe("Failed to complete Android background processing", error, stack);
    } finally {
      await _cleanup();
    }
  }

  @override
  Future<void> onIosUpload(bool isRefresh, int? maxSeconds) async {
    try {
      _logger.info('iOS background upload started with maxSeconds: ${maxSeconds}s');
      final sw = Stopwatch()..start();

      final timeout = isRefresh ? const Duration(seconds: 5) : Duration(minutes: _isBackupEnabled ? 3 : 6);
      await _syncAssets(hashTimeout: timeout);

      final backupFuture = _handleBackup();
      if (maxSeconds != null) {
        await backupFuture.timeout(Duration(seconds: maxSeconds - 1), onTimeout: () {});
      } else {
        await backupFuture;
      }

      sw.stop();
      _logger.info("iOS background upload completed in ${sw.elapsed.inSeconds}s");
    } catch (error, stack) {
      _logger.severe("Failed to complete iOS background upload", error, stack);
    } finally {
      await _cleanup();
    }
  }

  @override
  Future<void> cancel() async {
    _logger.warning("Background worker cancelled");
    try {
      await _cleanup();
    } catch (error, stack) {
      debugPrint('Failed to cleanup background worker: $error with stack: $stack');
    }
  }

  Future<void> _cleanup() async {
    if (_isCleanedUp) {
      return;
    }

    try {
      _isCleanedUp = true;
      _logger.info("Cleaning up background worker");
      await _ref.read(backgroundSyncProvider).cancel();
      await _ref.read(backgroundSyncProvider).cancelLocal();
      if (_isar.isOpen) {
        await _isar.close();
      }
      await _drift.close();
      await _driftLogger.close();
      _ref.dispose();
      _lockManager.releaseLock();
      _logger.info("Background worker resources cleaned up");
    } catch (error, stack) {
      debugPrint('Failed to cleanup background worker: $error with stack: $stack');
    }
  }

  Future<void> _handleBackup({bool processBulk = true}) async {
    if (!_isBackupEnabled) {
      return;
    }

    final currentUser = _ref.read(currentUserProvider);
    if (currentUser == null) {
      return;
    }

    if (processBulk) {
      return _ref.read(driftBackupProvider.notifier).handleBackupResume(currentUser.id);
    }

    final activeTask = await _ref.read(uploadServiceProvider).getActiveTasks(currentUser.id);
    if (activeTask.isNotEmpty) {
      await _ref.read(uploadServiceProvider).resumeBackup();
    } else {
      await _ref.read(uploadServiceProvider).startBackupSerial(currentUser.id);
    }
  }

  Future<void> _syncAssets({Duration? hashTimeout}) async {
    final futures = <Future<void>>[];

    final localSyncFuture = _ref.read(backgroundSyncProvider).syncLocal().then((_) async {
      if (_isCleanedUp) {
        return;
      }

      var hashFuture = _ref.read(backgroundSyncProvider).hashAssets();
      if (hashTimeout != null) {
        hashFuture = hashFuture.timeout(
          hashTimeout,
          onTimeout: () {
            // Consume cancellation errors as we want to continue processing
          },
        );
      }

      return hashFuture;
    });

    futures.add(localSyncFuture);
    futures.add(_ref.read(backgroundSyncProvider).syncRemote());

    await Future.wait(futures);
  }
}

/// Native entry invoked from the background worker. If renaming or moving this to a different
/// library, make sure to update the entry points and URI in native workers as well
@pragma('vm:entry-point')
Future<void> backgroundSyncNativeEntrypoint() async {
  WidgetsFlutterBinding.ensureInitialized();
  DartPluginRegistrant.ensureInitialized();

  final (isar, drift, logDB) = await Bootstrap.initDB();
  await Bootstrap.initDomain(isar, drift, logDB, shouldBufferLogs: false);
  await BackgroundWorkerBgService(isar: isar, drift: drift, driftLogger: logDB).init();
}