refactor entire frontend

frontend/lib/backend.dart

@@ -1,27 +1,31 @@
+
 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(username) {
-    _socket!.send(
-        json.encode({'username': username})
-    );
+  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');
-      auth("the-user");
-      ping(); 
     });
     _socket!.onError.listen((event) {
       print('Error: $event');
@@ -31,6 +35,9 @@ class Backend {
       print('Disconnected. Attempting to reconnect...');
       _reconnect();
     });
+    _socket!.onMessage.listen((event) {
+      _handleIncomingMessage(event.data);
+    });
   }
 
   static void _reconnect() {
@@ -39,8 +46,65 @@ class Backend {
     });
   }
 
+  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) {
+    if (_socket!= null && _socket!.readyState == WebSocket.OPEN) {
       final data = json.encode({'path': 'ping'});
       _socket!.send(data);
       print('Ping sent: $data');