message edit/update functionality

frontend/lib/chat_screen.dart

@@ -57,6 +57,7 @@ class _ChatScreenState extends State<ChatScreen> {
 
   // UI State
   Set<int> expandedThreads = {};
+  int? editingMessageId = null;
 
   // Internal Funcionality
   Offset? _longPressOffset;
@@ -153,21 +154,39 @@ class _ChatScreenState extends State<ChatScreen> {
     });
   }
 
-  void sendMessage(String content) async {
-    if (content.trim().isEmpty) return; // Don't send empty messages
+  void sendMessage() async {
+    final content =  _textController.text;
     _textController.clear();
+    if (content.trim().isEmpty) return; // Don't send empty messages
 
-    final newMessage = Message(sender: "user", content: content, threadId: currentThreadId);
-    Backend.sendAction("send-chat-message", {
-      'chatId': widget.chatId,
-      'content': content,
-      'threadId': currentThreadId,
-    }).then((response) {
-      if (response['error'] != null) {
-        print("Error sending chat message: ${response['error']}");
-      }
-    });
-    addMessage(newMessage);
+    if (editingMessageId == null) {
+      Backend.sendAction("send-chat-message", {
+        'chatId': widget.chatId,
+        'content': content,
+        'threadId': currentThreadId,
+      }).then((response) {
+        if (response['error'] != null) {
+          print("Error sending chat message: ${response['error']}");
+        }
+      });
+
+      final newMessage = Message(sender: "user", content: content, threadId: currentThreadId);
+      addMessage(newMessage);
+    } else {
+      Backend.sendAction("update-chat-message", {
+        'messageId': editingMessageId,
+        'content': content,
+      }).then((response) {
+        if (response['error'] != null) {
+          print("Error updating message: ${response['error']}");
+        }
+      });
+
+      Message message = _messages.firstWhere((element) => element.id == editingMessageId!);
+      setState(() {
+        message.content = content;
+      });
+    }
   }
 
   void createThread () async {
@@ -186,7 +205,7 @@ class _ChatScreenState extends State<ChatScreen> {
     return messageColor;
   }
 
-  void _showMessageContextMenu(BuildContext context, Offset position) {
+  void _showMessageContextMenu(BuildContext context, Message message, Offset position) {
     showMenu(
       context: context,
       position: RelativeRect.fromLTRB(position.dx, position.dy, position.dx + 1, position.dy + 1),
@@ -201,8 +220,10 @@ class _ChatScreenState extends State<ChatScreen> {
         PopupMenuItem(
           child: Text('Edit'),
           onTap: () {
-            // TODO: Implement Edit functionality
-            print('Edit clicked');
+            _textController.text = message.content;
+            setState(() {
+              editingMessageId = message.id;
+            });
           },
         ),
         PopupMenuItem(
@@ -282,11 +303,11 @@ class _ChatScreenState extends State<ChatScreen> {
                       _longPressOffset = details.globalPosition;
                     },
                     onLongPress: () {
-                      _showMessageContextMenu(context, _longPressOffset!);
+                      _showMessageContextMenu(context, message, _longPressOffset!);
                       _longPressOffset = null;
                     },
                     onSecondaryTapUp: (details) {
-                      _showMessageContextMenu(context, details.globalPosition);
+                      _showMessageContextMenu(context, message, details.globalPosition);
                     },
                     child: Padding(
                       padding: isWideScreen ? message.padding : EdgeInsets.zero,
@@ -299,7 +320,14 @@ class _ChatScreenState extends State<ChatScreen> {
                             color: getMessageColor(context),
                             borderRadius: BorderRadius.circular(12),
                           ),
-                          child: Text(message.content),
+                          child: SelectableText(
+                            message.content,
+                            toolbarOptions: ToolbarOptions(
+                              copy: true,
+                              selectAll: false,
+                            ),
+                            onTap: () {},
+                          ),
                         ),
                       ),
                     ),
@@ -315,13 +343,16 @@ class _ChatScreenState extends State<ChatScreen> {
             padding: const EdgeInsets.all(8.0),
             child: Column(
               children: [
+                if (editingMessageId!= null) ...[
+                  Text('Editing ${editingMessageId}'),
+                ],
                 Expanded(
                   child: KeyboardListener(
                     focusNode: _inputFocusNode,
                     onKeyEvent: (event) {
                       // TODO: Probably doing this in the input focus node would be cleaner
                       if (HardwareKeyboard.instance.isControlPressed && HardwareKeyboard.instance.isLogicalKeyPressed(LogicalKeyboardKey.enter)) {
-                        sendMessage(_textController.text);
+                        sendMessage();
                         //return KeyEventResult.handled;
                       }
                       //return KeyEventResult.ignored;
@@ -338,7 +369,7 @@ class _ChatScreenState extends State<ChatScreen> {
                   children: [
                     ElevatedButton(
                       onPressed: () {
-                        sendMessage(_textController.text);
+                        sendMessage();
                       },
                       child: Text('Send'),
                     ),
@@ -349,6 +380,17 @@ class _ChatScreenState extends State<ChatScreen> {
                       },
                       child: Text('Start New Topic'),
                     ),
+                    if (editingMessageId!= null) ...[
+                      ElevatedButton(
+                        onPressed: () {
+                          _textController.text = "";
+                          setState(() {
+                            editingMessageId = null;
+                          });
+                        },
+                        child: Text('Cancel Edit'),
+                      )
+                    ],
                   ],
                 ),
               ],