fixed bug that prevents sending messages if reply was triggered in a different chat

lib/api/errors/talk_exception.dart

@@ -4,16 +4,22 @@ import 'app_exception.dart';
 class TalkException extends AppException {
   final TalkError source;
 
-  TalkException(this.source)
+  TalkException(this.source, {String? technicalDetails})
     : super(
         userMessage: _mapMessage(source),
         technicalDetails:
+            technicalDetails ??
             'Talk ${source.status} (${source.code}): ${source.message}',
         allowRetry: source.code >= 500,
       );
 
   static String _mapMessage(TalkError e) {
     switch (e.code) {
+      case 400:
+        return 'Talk hat diese Anfrage abgelehnt. Bitte lade den Chat neu und '
+            'versuche es erneut.';
+      case 413:
+        return 'Diese Nachricht ist zu lang.';
       case 401:
         return 'Bitte melde dich erneut an, um auf Talk zuzugreifen.';
       case 403:

lib/api/marianumcloud/talk/talk_api.dart

@@ -6,8 +6,10 @@ import '../../api_params.dart';
 import '../../api_response.dart';
 import '../../errors/network_exception.dart';
 import '../../errors/parse_exception.dart';
+import '../../errors/talk_exception.dart';
 import '../../http_errors.dart';
 import '../nextcloud_ocs.dart';
+import 'talk_error.dart';
 
 abstract class TalkApi<T extends ApiResponse?> {
   String path;
@@ -49,6 +51,16 @@ abstract class TalkApi<T extends ApiResponse?> {
       // logs surface the cause instead of just the bare status code.
       final detail = httpErrorDetail('Talk $endpoint', data.body, status);
       log(detail);
+      // Talk's own codes need their own wording: a 400/412/413 here is a
+      // rejected request, not a struggling server, and "try again later"
+      // would send the user in circles. 401/403/404 keep the shared mapping
+      // so the auth handling stays in one place.
+      if (status == 400 || status == 412 || status == 413 || status == 429) {
+        throw TalkException(
+          TalkError('failure', status, ''),
+          technicalDetails: detail,
+        );
+      }
       throwForStatus(status, detail);
     }
 

lib/state/app/modules/chat/bloc/chat_bloc.dart

@@ -93,9 +93,13 @@ class ChatBloc
     _stopLongPoll();
     add(
       Emit(
+        // A reply reference belongs to the room it was picked in — carrying it
+        // into the next chat makes every send there fail on an unrelated
+        // parent id. ChatTextfield restores this room's draft reply after.
         (s) => s.copyWith(
           currentToken: token,
           chatResponse: null,
+          referenceMessageId: null,
           hasMoreOld: true,
           isLoadingOlder: false,
         ),

lib/view/pages/talk/widgets/chat_textfield.dart

@@ -11,6 +11,7 @@ import '../../../../api/marianumcloud/talk/send_message/send_message_params.dart
 import '../../../../api/marianumcloud/talk/share_files_to_chat.dart';
 import '../../../../api/marianumcloud/webdav/webdav_api.dart';
 import '../../../../state/app/modules/chat/bloc/chat_bloc.dart';
+import '../../../../state/app/modules/chat/bloc/chat_state.dart';
 import '../../../../state/app/modules/settings/bloc/settings_cubit.dart';
 import '../../../../widget/async_action_button.dart';
 import '../../../../widget/demo_restricted.dart';
@@ -216,11 +217,27 @@ class _ChatTextfieldState extends State<ChatTextfield> {
     _setDraft(newText);
   }
 
+  /// Reply target for the next send, or null when there is none. Requires the
+  /// referenced message to sit in this room's loaded history — the same
+  /// criterion the reply banner renders on, so what the user sees is what gets
+  /// sent. Talk rejects the whole message when the parent id is foreign to the
+  /// room, so a leftover reference would otherwise block the chat entirely.
+  String? _replyTargetFor(ChatState? chatState) {
+    final referenceId = chatState?.referenceMessageId;
+    if (referenceId == null) return null;
+    if (chatState!.currentToken != widget.sendToToken) return null;
+    final messages = chatState.chatResponse?.data;
+    if (messages == null || !messages.any((e) => e.id == referenceId)) {
+      return null;
+    }
+    return referenceId.toString();
+  }
+
   Future<void> _sendMessage(ChatBloc chatBloc) async {
     if (_textBoxController.text.isEmpty) return;
     if (guardDemoAction(context)) return;
     final text = _textBoxController.text;
-    final replyTo = chatBloc.state.data?.referenceMessageId?.toString();
+    final replyTo = _replyTargetFor(chatBloc.state.data);
     final ownToken = widget.sendToToken;
     setState(() => _sendError = null);
     await SendMessage(