import 'dart:io';
import 'dart:async';
import 'dart:convert';
import 'package:shelf/shelf.dart';
import 'package:shelf/shelf_io.dart' as shelf_io;
import 'package:shelf_static/shelf_static.dart';
import 'package:shelf_router/shelf_router.dart';
import 'package:http/http.dart' as http;
import 'package:args/args.dart';
import 'database/database.dart';
import 'models/user.dart';
import 'models/playlist.dart';
import 'models/playlist_config.dart';
import 'api/auth_handler.dart';
import 'api/users_handler.dart';
import 'api/playlists_handler.dart';
import 'api/settings_handler.dart';
import 'api/streaming_handler.dart';
import 'middleware/auth_middleware.dart';
import 'middleware/security_middleware.dart';
import 'services/cleanup_service.dart';

void main(List<String> args) async {
  // Parse command line arguments
  final parser = ArgParser()
    ..addOption('port', abbr: 'p', defaultsTo: '8089')
    ..addOption('path', defaultsTo: '/app/web');

  final result = parser.parse(args);
  final port = int.parse(result['port']);
  final webPath = result['path'];

  // Initialize database
  final db = AppDatabase();
  await db.init();
  await db.seedAdmin();

  // Initialize Streaming Subsystem
  await initStreaming();

  // Create API handlers
  final authHandler = AuthHandler(db);
  final playlistsHandler = PlaylistsHandler(db);
  final usersHandler = UsersHandler(db);
  final settingsHandler = SettingsHandler(db);

  // Setup router
  final apiRouter = Router()
    // Auth endpoints
    ..mount('/api/auth', authHandler.router)
    // Playlists endpoints
    ..mount(
      '/api/playlists',
      const Pipeline()
          .addMiddleware(authMiddleware(db))
          .addHandler(playlistsHandler.router.call),
    )
    // Users endpoints
    ..mount(
      '/api/users',
      const Pipeline()
          .addMiddleware(authMiddleware(db))
          .addHandler(usersHandler.router.call),
    )
    // Settings endpoints
    ..mount(
      '/api/settings',
      const Pipeline()
          .addMiddleware(authMiddleware(db))
          .addHandler(settingsHandler.router.call),
    );

  // Initialize Cleanup Service
  final cleanupService = CleanupService();
  cleanupService.addTarget(Directory.systemTemp);
  cleanupService.addTarget(Directory('/app/data/logs'));
  cleanupService.addTarget(Directory('/app/data/tmp'));

  cleanupService.start();

  // Admin Routes (protected)
  apiRouter.mount(
    '/api/admin',
    const Pipeline()
        .addMiddleware(authMiddleware(db))
        .addHandler((Request request) {
      final router = Router();

      // POST /api/admin/purge
      router.post('/purge', (Request req) async {
        final user = req.context['user'] as User?;
        if (user == null || !user.isAdmin) {
          return Response.forbidden(
              jsonEncode({'error': 'Admin access required'}));
        }

        final result = await cleanupService.runCleanup();
        return Response.ok(
          jsonEncode(result),
          headers: {'content-type': 'application/json'},
        );
      });

      return router(request);
    }),
  );

  // Create static handler
  final baseStaticHandler = createStaticHandler(
    webPath,
    defaultDocument: 'index.html',
    listDirectories: false,
  );

  // Wrap static handler to enforce cache policies
  FutureOr<Response> staticHandler(Request request) async {
    final response = await baseStaticHandler(request);

    // Disable cache for entry points to ensure updates are seen immediately
    final path = request.url.path;
    if (path.isEmpty ||
        path == 'index.html' ||
        path.endsWith('.js') ||
        path.endsWith('.json')) {
      return response.change(
        headers: {
          'Cache-Control': 'no-store, no-cache, must-revalidate, max-age=0',
          'Pragma': 'no-cache',
          'Expires': '0',
        },
      );
    }

    // Allow aggressive caching for hashed assets
    return response.change(
      headers: {
        'Cache-Control': 'public, max-age=86400',
      },
    );
  }

  // Helper to get playlist from request
  Future<PlaylistConfig?> getPlaylist(Request request) async {
    Playlist? playlist;

    final user = request.context['user'] as User?;
    if (user != null) {
      final playlists = db.getPlaylists(user.id);
      if (playlists.isNotEmpty) playlist = playlists.first;
    } else {
      // Fallback: Try to find a playlist for any user if no specific user is logged in
      final users = db.getAllUsers();
      if (users.isNotEmpty) {
        final playlists = db.getPlaylists(users[0].id);
        if (playlists.isNotEmpty) playlist = playlists.first;
      }
    }

    if (playlist != null) {
      return PlaylistConfig(
        id: playlist.id,
        name: playlist.name,
        dns: playlist.serverUrl,
        username: playlist.username,
        password: playlist.password,
        createdAt: playlist.createdAt,
        isActive: true,
      );
    }
    return null;
  }

  // Create Streaming Router (Mount handlers on correct paths)
  final streamingRouter = Router()
    ..mount(
        '/api/live',
        createLiveStreamHandler(getPlaylist,
            isGpuEnabled: db.isNvidiaGpuEnabled))
    ..mount(
        '/api/vod',
        createVodStreamHandler(getPlaylist,
            isGpuEnabled: db.isNvidiaGpuEnabled));

  // Main handler with API proxy and NEW Streaming Handlers
  final handler = Cascade()
      .add(apiRouter.call) /* Standard API endpoints */
      .add(_createXtreamProxyHandler()) /* Keep for general API calls */
      .add(streamingRouter.call) /* Streaming endpoints */
      .add(staticHandler)
      .handler;

  // Add middleware
  final pipeline = const Pipeline()
      .addMiddleware(logRequests())
      .addMiddleware(securityHeadersMiddleware())
      .addMiddleware(honeypotMiddleware())
      .addMiddleware(rateLimitMiddleware())
      .addMiddleware(_corsMiddleware())
      .addHandler(handler);

  // Start server
  final server = await shelf_io.serve(
    pipeline,
    InternetAddress.anyIPv4,
    port,
  );

  print('Server started on port ${server.port}');
  print('Serving static files from: $webPath');
  print('REST API available at: /api/auth/* and /api/playlists/*');
  print('Xtream proxy available at: /api/xtream/*');

  // Clean expired sessions periodically (every hour)
  Timer.periodic(const Duration(hours: 1), (_) {
    db.cleanExpiredSessions();
    print('Cleaned expired sessions');
  });
}

/// CORS middleware to allow cross-origin requests
Middleware _corsMiddleware() {
  return (Handler handler) {
    return (Request request) async {
      // Handle preflight requests
      if (request.method == 'OPTIONS') {
        return Response.ok('', headers: _corsHeaders);
      }

      // Process request and add CORS headers to response
      final response = await handler(request);
      return response.change(headers: _corsHeaders);
    };
  };
}

final _corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Methods': 'GET, POST, PUT, DELETE, OPTIONS',
  'Access-Control-Allow-Headers': 'Origin, Content-Type, Accept, Authorization',
};

/// Create Xtream proxy handler with M3U8 URL rewriting support
Handler _createXtreamProxyHandler() {
  return (Request request) async {
    final path = request.url.path;

    // Only handle /api/xtream/* requests
    if (!path.startsWith('api/xtream/')) {
      return Response.notFound('Not found');
    }

    try {
      // Extract target URL from request
      // Format: /api/xtream/http://server:port/path
      String apiPath = path.substring('api/xtream/'.length);

      // Decode URL if it's encoded
      if (apiPath.startsWith('http%3A') || apiPath.startsWith('https%3A')) {
        apiPath = Uri.decodeComponent(apiPath);
      }

      if (!apiPath.startsWith('http://') && !apiPath.startsWith('https://')) {
        return Response.badRequest(
          body: 'Invalid API URL. Expected format: /api/xtream/http://...',
        );
      }

      String fullUrl = apiPath;
      if (request.url.query.isNotEmpty) {
        if (fullUrl.contains('?')) {
          fullUrl = '$fullUrl&${request.url.query}';
        } else {
          fullUrl = '$fullUrl?${request.url.query}';
        }
      }

      final targetUrl = Uri.parse(fullUrl);

      final proxyHeaders = {
        'User-Agent': 'VLC/3.0.18 LibVLC/3.0.18',
        'Accept': '*/*',
        'Accept-Encoding': 'identity',
        'Connection': 'keep-alive',
      };

      http.Response response;
      if (request.method == 'GET') {
        response = await http.get(targetUrl, headers: proxyHeaders).timeout(
              const Duration(seconds: 30),
              onTimeout: () => http.Response('Request timeout', 504),
            );
      } else if (request.method == 'POST') {
        final body = await request.readAsString();
        response = await http
            .post(targetUrl, headers: proxyHeaders, body: body)
            .timeout(
              const Duration(seconds: 30),
              onTimeout: () => http.Response('Request timeout', 504),
            );
      } else {
        return Response(405, body: 'Method not allowed');
      }

      return Response(
        response.statusCode,
        body: response.bodyBytes,
        headers: {
          'content-type':
              response.headers['content-type'] ?? 'application/json',
          'access-control-allow-origin': '*',
        },
      );
    } catch (e, stackTrace) {
      print('Proxy error: $e');
      print(stackTrace);
      return Response.internalServerError(
        body: jsonEncode({'error': 'Proxy error', 'message': e.toString()}),
        headers: {'content-type': 'application/json'},
      );
    }
  };
}