import 'dart:html';
import 'dart:convert';
import 'dart:async'; // Import for handling Completers

class Backend {
  static WebSocket? _socket;
  static String? _url;
  static String? _username;
  static Map<int, Completer> _pendingActions = {};
  static Map<int, StreamController<Map<String, dynamic>>> _chatControllers = {};
  static int _nextNonce = 0; // Tracking nonce for each action
  static StreamController<Map<String, dynamic>> _packetStreamController = StreamController.broadcast();

  static void setup(String url) {
    _url = url;
    connect();
  }

  static void auth(String username, String password) {
    _socket!.send(json.encode({'username': username, 'password': password}));
    _username = username;
  }

  static void connect() {
    _socket = WebSocket(_url!);
    _socket!.onOpen.listen((event) {
      print('Connected to the WebSocket server');
    });
    _socket!.onError.listen((event) {
      print('Error: $event');
      _reconnect();
    });
    _socket!.onClose.listen((event) {
      print('Disconnected. Attempting to reconnect...');
      _reconnect();
    });
    _socket!.onMessage.listen((event) {
      _handleIncomingMessage(event.data);
    });
  }

  static void _reconnect() {
    Future.delayed(Duration(seconds: 5), () {
      connect();
    });
  }

  static Future<dynamic> sendAction(String action, Map<String, dynamic> body) {
    int nonce = _nextNonce++;
    Completer completer = Completer();
    _pendingActions[nonce] = completer;

    final packet = {
      'action': action,
      'nonce': nonce,
      'body': body,
    };
    _socket!.send(json.encode(packet));

    return completer.future.then((response) {
      _pendingActions.remove(nonce); // Clean up the mapping
      return response;
    });
  }

  static void _handleIncomingMessage(String data) {
    var jsonData = json.decode(data);
    print("Incoming Packet: $jsonData");
    
    if (jsonData['nonce'] != null) {
      int nonce = jsonData['nonce'];
      if (_pendingActions.containsKey(nonce)) {
        // Complete the response
        _pendingActions[nonce]!.complete(jsonData);
      } else {
        print("Orphan response for action nonce $nonce");
      }
    } else if (jsonData['action'] == 'chat-message') {
      int chatId = jsonData['chatId'];
      final controller = _chatControllers[chatId];
      if (controller != null && !controller.isClosed) {
        controller.add(jsonData);
      } else {
        print("No active listeners for chatId $chatId");
      }
    } else {
      _packetStreamController.add(jsonData);
    }
  }

  static Stream<Map<String, dynamic>> chatMessages(int chatId) {
    if (!_chatControllers.containsKey(chatId) || _chatControllers[chatId]!.isClosed) {
      _chatControllers[chatId] = StreamController<Map<String, dynamic>>.broadcast();
    }
    return _chatControllers[chatId]!.stream;
  }

  static void removeChatListener(int chatId) {
    final controller = _chatControllers.remove(chatId);
    if (controller != null && !controller.isClosed) {
      controller.close();
    }
  }

  static void ping() {
    if (_socket!= null && _socket!.readyState == WebSocket.OPEN) {
      final data = json.encode({'path': 'ping'});
      _socket!.send(data);
      print('Ping sent: $data');
    }
  }
}