Merge pull request #363 from cogwheel0/fix-model-selection

feat(api): Improve default model selection with fallback mechanism

lib/core/services/api_service.dart

@@ -794,15 +794,7 @@ class ApiService {
       DebugLogger.log('settings-ok', scope: 'api/user-settings');
 
       final data = response.data;
-      if (data is! Map<String, dynamic>) {
+      if (data is Map<String, dynamic>) {
-        DebugLogger.warning(
-          'settings-format',
-          scope: 'api/user-settings',
-          data: {'type': data.runtimeType},
-        );
-        return null;
-      }
-
         // Extract default model from ui.models array
         final ui = data['ui'];
         if (ui is Map<String, dynamic>) {
@@ -818,21 +810,51 @@ class ApiService {
             return defaultModel;
           }
         }
+      }
 
-      DebugLogger.warning('default-model-missing', scope: 'api/user-settings');
+      // Fallback: user has no default model configured, pick first available
-      return null;
+      // This fixes issue #353 where secondary accounts couldn't send messages
+      DebugLogger.log(
+        'default-model-fallback',
+        scope: 'api/user-settings',
+      );
+      return _getFirstAvailableModelId();
     } catch (e) {
       DebugLogger.error(
         'default-model-error',
         scope: 'api/user-settings',
         error: e,
       );
-      // Do not call admin-only configs endpoint here; let the caller
+      // Attempt fallback even on error
-      // handle fallback (e.g., first available model from /api/models).
+      return _getFirstAvailableModelId();
-      return null;
     }
   }
 
+  /// Returns the ID of the first available model, or null if none available.
+  ///
+  /// Used as a fallback when user has no default model configured.
+  Future<String?> _getFirstAvailableModelId() async {
+    try {
+      final models = await getModels();
+      if (models.isNotEmpty) {
+        final fallbackId = models.first.id;
+        DebugLogger.log(
+          'default-model-fallback-selected',
+          scope: 'api/user-settings',
+          data: {'id': fallbackId},
+        );
+        return fallbackId;
+      }
+    } catch (e) {
+      DebugLogger.error(
+        'default-model-fallback-failed',
+        scope: 'api/user-settings',
+        error: e,
+      );
+    }
+    return null;
+  }
+
   // Conversations - Updated to use correct OpenWebUI API
   Future<List<Conversation>> getConversations({int? limit, int? skip}) async {
     final pinnedFuture = _fetchChatCollection(