import 'dart:async';
import 'package:logger/logger.dart';
import 'package:real_estate_mobile/config/app_config.dart';
import 'package:real_estate_mobile/core/network/api_client.dart';
import 'package:real_estate_mobile/core/storage/secure_storage.dart';
import 'package:real_estate_mobile/features/messaging/data/models/message.dart';
import 'package:real_estate_mobile/features/support_chat/data/models/support_chat_models.dart';

// We'll use a simple WebSocket approach for now since socket_io_client needs to be added
// This will be a placeholder that uses REST polling until socket_io_client is added
import 'package:socket_io_client/socket_io_client.dart' as io;

final _log = Logger(printer: PrettyPrinter(methodCount: 0));

class SocketService {
  static final SocketService _instance = SocketService._();
  factory SocketService() => _instance;
  SocketService._();

  io.Socket? _socket;
  bool _isConnected = false;
  bool _intentionalDisconnect = false;
  String? _currentToken;

  // Stream controllers for events
  final _messageController = StreamController<ChatMessage>.broadcast();
  final _typingStartController = StreamController<Map<String, dynamic>>.broadcast();
  final _typingStopController = StreamController<Map<String, dynamic>>.broadcast();
  final _statusController = StreamController<Map<String, dynamic>>.broadcast();
  final _readController = StreamController<Map<String, dynamic>>.broadcast();
  final _connectionController = StreamController<bool>.broadcast();
  final _supportMessageController = StreamController<SupportMessage>.broadcast();
  final _supportTypingStartController = StreamController<Map<String, dynamic>>.broadcast();
  final _supportTypingStopController = StreamController<Map<String, dynamic>>.broadcast();

  Stream<ChatMessage> get onNewMessage => _messageController.stream;
  Stream<Map<String, dynamic>> get onTypingStart => _typingStartController.stream;
  Stream<Map<String, dynamic>> get onTypingStop => _typingStopController.stream;
  Stream<Map<String, dynamic>> get onStatusChange => _statusController.stream;
  Stream<Map<String, dynamic>> get onMessagesRead => _readController.stream;
  Stream<bool> get onConnectionChange => _connectionController.stream;
  Stream<SupportMessage> get onSupportMessage => _supportMessageController.stream;
  Stream<Map<String, dynamic>> get onSupportTypingStart => _supportTypingStartController.stream;
  Stream<Map<String, dynamic>> get onSupportTypingStop => _supportTypingStopController.stream;
  bool get isConnected => _isConnected;

  Future<void> connect() async {
    final token = await SecureStorage.getAccessToken();
    if (token == null) {
      _log.w('No access token for socket connection');
      return;
    }

    if (_socket?.connected == true && _currentToken == token) return;

    _currentToken = token;
    _intentionalDisconnect = false;

    // Strip /api/v1 from base URL for socket connection
    final apiUrl = AppConfig.apiBaseUrl;
    final baseUrl = apiUrl.replaceAll(RegExp(r'/api/v1/?$'), '');

    _socket?.disconnect();
    _socket?.dispose();

    _socket = io.io(baseUrl, io.OptionBuilder()
      .setTransports(['websocket', 'polling'])
      .setAuth({'token': token})
      .disableAutoConnect()
      .enableReconnection()
      .setReconnectionAttempts(double.maxFinite.toInt())
      .setReconnectionDelay(1000)
      .setReconnectionDelayMax(10000)
      .build(),
    );

    _socket!.onConnect((_) {
      _log.i('Socket connected: ${_socket!.id}');
      _isConnected = true;
      _connectionController.add(true);
    });

    _socket!.onDisconnect((reason) {
      _log.w('Socket disconnected: $reason');
      _isConnected = false;
      _connectionController.add(false);

      if (reason == 'io server disconnect' && !_intentionalDisconnect) {
        _log.w('Server rejected connection - token likely expired');
        _reconnectWithFreshToken();
      }
    });

    _socket!.onConnectError((error) {
      _log.e('Socket connect error: $error');
      _isConnected = false;
      _connectionController.add(false);
    });

    _socket!.onReconnect((_) {
      _log.i('Socket reconnected successfully');
    });

    _socket!.onReconnectAttempt((attempt) {
      _log.w('Socket reconnection attempt #$attempt');
    });

    _socket!.onReconnectError((error) {
      _log.e('Socket reconnection error: $error');
    });

    // Listen for events
    _socket!.on('new_message', (data) {
      try {
        final message = ChatMessage.fromJson(data as Map<String, dynamic>);
        _messageController.add(message);
      } catch (e) {
        _log.e('Error parsing new_message: $e');
      }
    });

    _socket!.on('typing_start', (data) {
      _typingStartController.add(Map<String, dynamic>.from(data as Map));
    });

    _socket!.on('typing_stop', (data) {
      _typingStopController.add(Map<String, dynamic>.from(data as Map));
    });

    _socket!.on('user_status_change', (data) {
      _statusController.add(Map<String, dynamic>.from(data as Map));
    });

    _socket!.on('messages_read', (data) {
      _readController.add(Map<String, dynamic>.from(data as Map));
    });

    // Support chat events
    _socket!.on('support_new_message', (data) {
      try {
        final message = SupportMessage.fromJson(data as Map<String, dynamic>);
        _supportMessageController.add(message);
      } catch (e) {
        _log.e('Error parsing support_new_message: $e');
      }
    });

    _socket!.on('support_typing_start', (data) {
      _supportTypingStartController.add(Map<String, dynamic>.from(data as Map));
    });

    _socket!.on('support_typing_stop', (data) {
      _supportTypingStopController.add(Map<String, dynamic>.from(data as Map));
    });

    _socket!.connect();
  }

  Future<void> _reconnectWithFreshToken() async {
    // Wait briefly for any in-flight REST token refresh to complete
    await Future.delayed(const Duration(milliseconds: 500));

    final token = await SecureStorage.getAccessToken();
    if (token == null) return;

    // If token hasn't changed, try triggering a refresh via a lightweight API call
    if (token == _currentToken) {
      try {
        // Make a lightweight call that triggers the API client's 401 interceptor
        // which auto-refreshes the token
        final dio = ApiClient.instance.dio;
        await dio.get('/auth/me');
        final refreshedToken = await SecureStorage.getAccessToken();
        if (refreshedToken == null || refreshedToken == _currentToken) return;
        _currentToken = refreshedToken;
      } catch (_) {
        return; // Token refresh failed — user will need to re-login
      }
    } else {
      _currentToken = token;
    }

    _socket?.io.options?['auth'] = {'token': _currentToken};
    _socket?.connect();
  }

  /// Ensure socket is connected — reconnect if needed.
  Future<void> ensureConnected() async {
    if (_socket?.connected == true) return;
    await connect();
  }

  void disconnect() {
    _intentionalDisconnect = true;
    _socket?.disconnect();
    _socket?.dispose();
    _socket = null;
    _isConnected = false;
    _currentToken = null;
  }

  Future<void> joinConversation(String conversationId) async {
    if (_socket == null || !_isConnected) return;
    final completer = Completer<void>();
    _socket!.emitWithAck('join_conversation', {'conversationId': conversationId},
      ack: (data) => completer.complete(),
    );
    await completer.future.timeout(
      const Duration(seconds: 10),
      onTimeout: () => _log.w('join_conversation timeout'),
    );
  }

  void leaveConversation(String conversationId) {
    _socket?.emit('leave_conversation', {'conversationId': conversationId});
  }

  Future<ChatMessage?> sendMessage(
    String conversationId,
    Map<String, dynamic> messageData,
  ) async {
    if (_socket == null || !_isConnected) return null;

    final completer = Completer<ChatMessage?>();
    _socket!.emitWithAck('send_message', {
      'conversationId': conversationId,
      'message': messageData,
    }, ack: (data) {
      try {
        final response = data as Map<String, dynamic>;
        if (response['success'] == true && response['message'] != null) {
          completer.complete(
            ChatMessage.fromJson(response['message'] as Map<String, dynamic>),
          );
        } else {
          completer.complete(null);
        }
      } catch (e) {
        completer.complete(null);
      }
    });

    return completer.future.timeout(
      const Duration(seconds: 10),
      onTimeout: () => null,
    );
  }

  void startTyping(String conversationId) {
    _socket?.emit('typing_start', {'conversationId': conversationId});
  }

  void stopTyping(String conversationId) {
    _socket?.emit('typing_stop', {'conversationId': conversationId});
  }

  /// Emit a raw event (used by support chat)
  void emitRaw(String event, Map<String, dynamic> data) {
    _socket?.emit(event, data);
  }

  void markAsRead(String conversationId) {
    _socket?.emit('mark_read', {'conversationId': conversationId});
  }

  void dispose() {
    disconnect();
    _messageController.close();
    _typingStartController.close();
    _typingStopController.close();
    _statusController.close();
    _readController.close();
    _connectionController.close();
    _supportMessageController.close();
    _supportTypingStartController.close();
    _supportTypingStopController.close();
  }
}