import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:logging/logging.dart';
import 'package:shelf/shelf.dart';
import 'package:shelf/shelf_io.dart' as shelf_io;
import 'package:shelf_router/shelf_router.dart';

import 'package:focusflow_api/src/config/database.dart';
import 'package:focusflow_api/src/config/env.dart';
import 'package:focusflow_api/src/middleware/auth_middleware.dart';
import 'package:focusflow_api/src/middleware/cors_middleware.dart';
import 'package:focusflow_api/src/middleware/error_handler.dart';
import 'package:focusflow_api/src/middleware/logging_middleware.dart';
import 'package:focusflow_api/src/middleware/rate_limit_middleware.dart';
import 'package:focusflow_api/src/modules/auth/auth_routes.dart';
import 'package:focusflow_api/src/modules/auth/auth_service.dart';
import 'package:focusflow_api/src/modules/auth/password_hasher.dart';
import 'package:focusflow_api/src/modules/auth/token_service.dart';
import 'package:focusflow_api/src/modules/rewards/reward_engine.dart';
import 'package:focusflow_api/src/modules/rewards/reward_routes.dart';
import 'package:focusflow_api/src/modules/rewards/reward_service.dart';
import 'package:focusflow_api/src/modules/rooms/room_routes.dart';
import 'package:focusflow_api/src/modules/rooms/room_service.dart';
import 'package:focusflow_api/src/modules/streaks/streak_repository.dart';
import 'package:focusflow_api/src/modules/streaks/streak_routes.dart';
import 'package:focusflow_api/src/modules/streaks/streak_service.dart';
import 'package:focusflow_api/src/modules/sync/sync_routes.dart';
import 'package:focusflow_api/src/modules/sync/sync_service.dart';
import 'package:focusflow_api/src/modules/tasks/dopamine_scorer.dart';
import 'package:focusflow_api/src/modules/tasks/task_repository.dart';
import 'package:focusflow_api/src/modules/tasks/task_routes.dart';
import 'package:focusflow_api/src/modules/tasks/task_service.dart';
import 'package:focusflow_api/src/modules/time/time_routes.dart';
import 'package:focusflow_api/src/modules/time/time_service.dart';

final _log = Logger('Server');

Future<void> main() async {
  // ── Logging ─────────────────────────────────────────────────────────
  Logger.root.level = Level.ALL;
  Logger.root.onRecord.listen((record) {
    // ignore: avoid_print
    print(
      '${record.time} [${record.level.name}] ${record.loggerName}: '
      '${record.message}',
    );
  });

  // ── Environment ─────────────────────────────────────────────────────
  Env.init();
  _log.info('Starting FocusFlow API (${Env.appEnv})');

  // ── Database ────────────────────────────────────────────────────────
  await Database.init();
  _log.info('Database pool opened');

  // ── Services (dependency injection) ─────────────────────────────────
  final tokenService = TokenService();
  final passwordHasher = PasswordHasher();
  final authService = AuthService(
    hasher: passwordHasher,
    tokenService: tokenService,
  );

  final rewardEngine = RewardEngine();
  final dopamineScorer = DopamineScorer();
  final taskRepository = TaskRepository();
  final taskService = TaskService(
    repository: taskRepository,
    scorer: dopamineScorer,
    rewardEngine: rewardEngine,
  );

  final streakRepository = StreakRepository();
  final streakService = StreakService(repository: streakRepository);

  final rewardService = RewardService(engine: rewardEngine);
  final timeService = TimeService();
  final syncService = SyncService();
  final roomService = RoomService();

  // ── Route modules ───────────────────────────────────────────────────
  final authRoutes = AuthRoutes(authService);
  final taskRoutes = TaskRoutes(taskService);
  final streakRoutes = StreakRoutes(streakService);
  final rewardRoutes = RewardRoutes(rewardService);
  final timeRoutes = TimeRoutes(timeService);
  final syncRoutes = SyncRoutes(syncService);
  final roomRoutes = RoomRoutes(roomService);

  // ── Router ──────────────────────────────────────────────────────────
  final app = Router();

  // Health check (public)
  app.get('/health', (Request request) {
    return Response.ok(
      jsonEncode({'status': 'ok'}),
      headers: {'Content-Type': 'application/json'},
    );
  });

  // Mount module routers
  app.mount('/api/v1/auth/', authRoutes.router.call);
  app.mount('/api/v1/tasks/', taskRoutes.router.call);
  app.mount('/api/v1/streaks/', streakRoutes.router.call);
  app.mount('/api/v1/rewards/', rewardRoutes.router.call);
  app.mount('/api/v1/time/', timeRoutes.router.call);
  app.mount('/api/v1/sync/', syncRoutes.router.call);
  app.mount('/api/v1/rooms/', roomRoutes.router.call);

  // ── Pipeline ────────────────────────────────────────────────────────
  final handler = const Pipeline()
      .addMiddleware(corsMiddleware())
      .addMiddleware(loggingMiddleware())
      .addMiddleware(errorHandlerMiddleware())
      .addMiddleware(rateLimitMiddleware())
      .addMiddleware(authMiddleware(tokenService))
      .addHandler(app.call);

  // ── Start server ────────────────────────────────────────────────────
  final port = Env.port;
  final server =
      await shelf_io.serve(handler, InternetAddress.anyIPv4, port);
  _log.info('Listening on http://${server.address.host}:${server.port}');

  // ── Graceful shutdown ───────────────────────────────────────────────
  late final StreamSubscription<ProcessSignal> sigintSub;
  late final StreamSubscription<ProcessSignal> sigtermSub;

  Future<void> shutdown() async {
    _log.info('Shutting down...');
    await server.close(force: false);
    await Database.close();
    _log.info('Server stopped');
    await sigintSub.cancel();
    await sigtermSub.cancel();
    exit(0);
  }

  sigintSub = ProcessSignal.sigint.watch().listen((_) => shutdown());
  sigtermSub = ProcessSignal.sigterm.watch().listen((_) => shutdown());
}