import 'dart:async';
import 'package:socket_io_client/socket_io_client.dart' as io;
import '../models/chat_message.dart';
import 'api.dart';

/// Service for managing real-time chat via WebSocket
class ChatService {
  static const String _wsBaseUrl = 'https://app.payfrit.com:3001';

  io.Socket? _socket;
  int? _currentTaskId;
  String? _userType;

  final StreamController<ChatMessage> _messageController =
      StreamController<ChatMessage>.broadcast();
  final StreamController<TypingEvent> _typingController =
      StreamController<TypingEvent>.broadcast();
  final StreamController<ChatEvent> _eventController =
      StreamController<ChatEvent>.broadcast();

  bool _isConnected = false;

  /// Stream of incoming messages
  Stream<ChatMessage> get messages => _messageController.stream;

  /// Stream of typing events
  Stream<TypingEvent> get typingEvents => _typingController.stream;

  /// Stream of chat events (user joined/left, chat ended)
  Stream<ChatEvent> get events => _eventController.stream;

  /// Whether the socket is currently connected
  bool get isConnected => _isConnected;

  /// Current task ID
  int? get currentTaskId => _currentTaskId;

  /// Connect to chat for a specific task
  Future<bool> connect({
    required int taskId,
    required String userToken,
    required String userType,
  }) async {
    // Disconnect if already connected to a different task
    if (_socket != null) {
      await disconnect();
    }

    _currentTaskId = taskId;
    _userType = userType;

    final completer = Completer<bool>();

    try {
      _socket = io.io(
        _wsBaseUrl,
        io.OptionBuilder()
            .setTransports(['websocket'])
            .disableAutoConnect()
            .build(),
      );

      _socket!.onConnect((_) {
        _isConnected = true;

        // Join the chat room
        _socket!.emit('join-chat', {
          'taskId': taskId,
          'userToken': userToken,
          'userType': userType,
        });
      });

      _socket!.on('joined', (data) {
        _eventController.add(ChatEvent(
          type: ChatEventType.joined,
          data: data,
        ));
        if (!completer.isCompleted) {
          completer.complete(true);
        }
      });

      _socket!.on('error', (data) {
        _eventController.add(ChatEvent(
          type: ChatEventType.error,
          message: data['message'] ?? 'Unknown error',
        ));
        if (!completer.isCompleted) {
          completer.complete(false);
        }
      });

      _socket!.on('new-message', (data) {
        final message = ChatMessage.fromJson(data as Map<String, dynamic>);
        _messageController.add(message);
      });

      _socket!.on('user-typing', (data) {
        _typingController.add(TypingEvent(
          userType: data['userType'] ?? '',
          userName: data['userName'] ?? '',
          isTyping: data['isTyping'] ?? false,
        ));
      });

      _socket!.on('user-joined', (data) {
        _eventController.add(ChatEvent(
          type: ChatEventType.userJoined,
          data: data,
        ));
      });

      _socket!.on('user-left', (data) {
        _eventController.add(ChatEvent(
          type: ChatEventType.userLeft,
          data: data,
        ));
      });

      _socket!.on('chat-ended', (data) {
        _eventController.add(ChatEvent(
          type: ChatEventType.chatEnded,
          message: data['message'] ?? 'Chat has ended',
        ));
      });

      _socket!.onDisconnect((_) {
        _isConnected = false;
        _eventController.add(ChatEvent(
          type: ChatEventType.disconnected,
        ));
      });

      _socket!.onConnectError((error) {
        _isConnected = false;
        if (!completer.isCompleted) {
          completer.complete(false);
        }
      });

      _socket!.connect();

      // Timeout after 10 seconds
      return completer.future.timeout(
        const Duration(seconds: 10),
        onTimeout: () => false,
      );
    } catch (e) {
      return false;
    }
  }

  /// Send a message via WebSocket
  /// Returns true if message was sent, false if not connected
  bool sendMessage(String text) {
    if (_socket == null || !_isConnected || _currentTaskId == null) {
      return false;
    }

    _socket!.emit('send-message', {
      'taskId': _currentTaskId,
      'message': text,
    });
    return true;
  }

  /// Send a message via HTTP (fallback)
  Future<int> sendMessageHttp({
    required int taskId,
    required String message,
    int? userId,
    String? senderType,
  }) async {
    return Api.sendChatMessage(
      taskId: taskId,
      message: message,
      userId: userId,
      senderType: senderType,
    );
  }

  /// Notify that user is typing
  void setTyping(bool isTyping) {
    if (_socket == null || !_isConnected || _currentTaskId == null) return;

    _socket!.emit('typing', {
      'taskId': _currentTaskId,
      'isTyping': isTyping,
    });
  }

  /// Close the chat (only workers can do this)
  void closeChat() {
    if (_socket == null || !_isConnected || _currentTaskId == null) return;

    _socket!.emit('chat-closed', {
      'taskId': _currentTaskId,
    });
  }

  /// Leave the chat room
  void leaveChat() {
    if (_socket == null || _currentTaskId == null) return;

    _socket!.emit('leave-chat', {
      'taskId': _currentTaskId,
    });
  }

  /// Disconnect from WebSocket
  Future<void> disconnect() async {
    if (_socket != null) {
      leaveChat();
      _socket!.disconnect();
      _socket!.dispose();
      _socket = null;
    }
    _isConnected = false;
    _currentTaskId = null;
    _userType = null;
  }

  /// Dispose the service and clean up streams
  void dispose() {
    disconnect();
    _messageController.close();
    _typingController.close();
    _eventController.close();
  }
}

/// Event for typing indicators
class TypingEvent {
  final String userType;
  final String userName;
  final bool isTyping;

  const TypingEvent({
    required this.userType,
    required this.userName,
    required this.isTyping,
  });
}

/// Event type for chat state changes
enum ChatEventType {
  joined,
  userJoined,
  userLeft,
  chatEnded,
  disconnected,
  error,
}

/// Event for chat state changes
class ChatEvent {
  final ChatEventType type;
  final String? message;
  final dynamic data;

  const ChatEvent({
    required this.type,
    this.message,
    this.data,
  });
}