fix: default model edge cases

lib/core/providers/app_providers.dart

@@ -259,6 +259,19 @@ final modelsProvider = FutureProvider<List<Model>>((ref) async {
 
 final selectedModelProvider = StateProvider<Model?>((ref) => null);
 
+// Track if the current model selection is manual (user-selected) or automatic (default)
+final isManualModelSelectionProvider = StateProvider<bool>((ref) => false);
+
+// Listen for settings changes and reset manual selection when default model changes
+final _settingsWatcherProvider = Provider<void>((ref) {
+  ref.listen<AppSettings>(appSettingsProvider, (previous, next) {
+    if (previous?.defaultModel != next.defaultModel) {
+      // Reset manual selection when default model changes
+      ref.read(isManualModelSelectionProvider.notifier).state = false;
+    }
+  });
+});
+
 // Cache timestamp for conversations to prevent rapid re-fetches
 final _conversationsCacheTimestamp = StateProvider<DateTime?>((ref) => null);
 
@@ -503,16 +516,20 @@ final loadConversationProvider = FutureProvider.family<Conversation, String>((
 
 // Provider to automatically load and set the default model from user settings or OpenWebUI
 final defaultModelProvider = FutureProvider<Model?>((ref) async {
+  // Initialize the settings watcher
+  ref.watch(_settingsWatcherProvider);
   // Watch user settings to refresh when default model changes
   ref.watch(appSettingsProvider);
   // Handle reviewer mode first
   final reviewerMode = ref.watch(reviewerModeProvider);
   if (reviewerMode) {
-    // Check if a model is already selected
+    // Check if a model is manually selected
     final currentSelected = ref.read(selectedModelProvider);
-    if (currentSelected != null) {
+    final isManualSelection = ref.read(isManualModelSelectionProvider);
+    
+    if (currentSelected != null && isManualSelection) {
       foundation.debugPrint(
-        'DEBUG: Model already selected in reviewer mode: ${currentSelected.name}',
+        'DEBUG: Manual model selected in reviewer mode: ${currentSelected.name}',
       );
       return currentSelected;
     }
@@ -522,7 +539,7 @@ final defaultModelProvider = FutureProvider<Model?>((ref) async {
     if (models.isNotEmpty) {
       final defaultModel = models.first;
       Future.microtask(() {
-        if (ref.read(selectedModelProvider) == null) {
+        if (!ref.read(isManualModelSelectionProvider)) {
           ref.read(selectedModelProvider.notifier).state = defaultModel;
           foundation.debugPrint(
             'DEBUG: Auto-selected demo model: ${defaultModel.name}',
@@ -538,15 +555,6 @@ final defaultModelProvider = FutureProvider<Model?>((ref) async {
   if (api == null) return null;
 
   try {
-    // Check if a model is already selected
-    final currentSelected = ref.read(selectedModelProvider);
-    if (currentSelected != null) {
-      foundation.debugPrint(
-        'DEBUG: Model already selected: ${currentSelected.name}',
-      );
-      return currentSelected;
-    }
-
     // Get all available models first
     final models = await ref.read(modelsProvider.future);
     if (models.isEmpty) {
@@ -554,15 +562,6 @@ final defaultModelProvider = FutureProvider<Model?>((ref) async {
       return null;
     }
 
-    // Double-check if a model was selected while we were loading
-    final checkSelected = ref.read(selectedModelProvider);
-    if (checkSelected != null) {
-      foundation.debugPrint(
-        'DEBUG: Model was selected during loading: ${checkSelected.name}',
-      );
-      return checkSelected;
-    }
-
     Model? selectedModel;
 
     // First check user's preferred default model
@@ -635,8 +634,8 @@ final defaultModelProvider = FutureProvider<Model?>((ref) async {
     // Defer the state update to avoid modifying providers during initialization
     final modelToSet = selectedModel;
     Future.microtask(() {
-      // Final check before setting
-      if (ref.read(selectedModelProvider) == null) {
+      // Only update if this is not a manual selection
+      if (!ref.read(isManualModelSelectionProvider)) {
         ref.read(selectedModelProvider.notifier).state = modelToSet;
         foundation.debugPrint('DEBUG: Set default model: ${modelToSet.name}');
       }
@@ -653,7 +652,7 @@ final defaultModelProvider = FutureProvider<Model?>((ref) async {
         final fallbackModel = models.first;
         // Defer the state update
         Future.microtask(() {
-          if (ref.read(selectedModelProvider) == null) {
+          if (!ref.read(isManualModelSelectionProvider)) {
             ref.read(selectedModelProvider.notifier).state = fallbackModel;
             foundation.debugPrint(
               'DEBUG: Fallback to first available model: ${fallbackModel.name}',

lib/core/services/api_service.dart

@@ -2530,7 +2530,7 @@ class ApiService {
       debugPrint('Persistent: Attempting to recover stream $streamId');
       // Restart the streaming request
       _streamSSE(data, streamController, messageId);
-    };
+    }
     
     // Declare variables that need to be accessible in catch block
     String? persistentStreamId;
@@ -2929,348 +2929,9 @@ class ApiService {
       }
     }
 
-  // Enhanced SSE parser that matches OpenWebUI's EventSourceParserStream approach
-  void _streamChatCompletionEnhanced(
-    Map<String, dynamic> data,
-    StreamController<String> streamController,
-    String messageId,
-  ) async {
-    try {
-      debugPrint('DEBUG: Making enhanced SSE request to /api/chat/completions');
 
-      final response = await _dio.post(
-        '/api/chat/completions',
-        data: data,
-        options: Options(
-          responseType: ResponseType.stream,
-          headers: {
-            'Accept': 'text/event-stream',
-            'Cache-Control': 'no-cache',
-            'Connection': 'keep-alive',
-          },
-          receiveTimeout: null,
-        ),
-      );
 
-      debugPrint('DEBUG: Enhanced SSE response received, status: ${response.statusCode}');
 
-      if (response.statusCode != 200) {
-        throw Exception('HTTP ${response.statusCode}: Failed to start streaming');
-      }
-
-      // Transform raw stream through SSE parser (like OpenWebUI's pipeline)
-      final rawStream = response.data.stream as Stream<List<int>>;
-      final textStream = StreamController<String>();
-      
-      // Convert bytes to text manually (like TextDecoderStream)
-      rawStream.listen(
-        (chunk) {
-          try {
-            final text = utf8.decode(chunk);
-            textStream.add(text);
-          } catch (e) {
-            debugPrint('DEBUG: Enhanced SSE decode error: $e');
-          }
-        },
-        onDone: () => textStream.close(),
-        onError: (error) => textStream.addError(error),
-      );
-      
-      // Apply SSE parsing (like EventSourceParserStream)
-      textStream.stream
-          .transform(_createEventSourceTransformer()) // Text → ParsedEvent
-          .listen(
-            (event) => _handleSSEEvent(event, streamController),
-            onDone: () {
-              debugPrint('DEBUG: Enhanced SSE stream completed');
-              streamController.close();
-            },
-            onError: (error) {
-              debugPrint('DEBUG: Enhanced SSE stream error: $error');
-              streamController.addError(error);
-            },
-          );
-    } catch (e) {
-      debugPrint('DEBUG: Enhanced SSE streaming error: $e');
-      streamController.addError(e);
-    }
-  }
-
-  // Create a stream transformer that parses SSE events (like EventSourceParserStream)
-  StreamTransformer<String, Map<String, String>> _createEventSourceTransformer() {
-    String buffer = '';
-    
-    return StreamTransformer<String, Map<String, String>>.fromHandlers(
-      handleData: (chunk, sink) {
-        buffer += chunk;
-        final lines = buffer.split('\n');
-        buffer = lines.removeLast(); // Keep incomplete line
-        
-        String? eventType;
-        String? data;
-        String? id;
-        
-        for (final line in lines) {
-          final trimmed = line.trim();
-          if (trimmed.isEmpty) {
-            // Empty line indicates end of event - emit it
-            if (data != null) {
-              sink.add({
-                'type': eventType ?? 'message',
-                'data': data,
-                if (id != null) 'id': id,
-              });
-            }
-            // Reset for next event
-            eventType = null;
-            data = null;
-            id = null;
-          } else if (trimmed.startsWith('data: ')) {
-            final eventData = trimmed.substring(6);
-            data = data == null ? eventData : '$data\n$eventData';
-          } else if (trimmed.startsWith('event: ')) {
-            eventType = trimmed.substring(7);
-          } else if (trimmed.startsWith('id: ')) {
-            id = trimmed.substring(4);
-          }
-          // Ignore retry: and other fields
-        }
-      },
-      handleDone: (sink) {
-        // Handle any remaining data
-        if (buffer.trim().isNotEmpty) {
-          sink.add({
-            'type': 'message',
-            'data': buffer.trim(),
-          });
-        }
-        sink.close();
-      },
-    );
-  }
-
-  // Handle individual SSE events (like OpenWebUI's event handler)
-  void _handleSSEEvent(Map<String, String> event, StreamController<String> streamController) {
-    final data = event['data'];
-    if (data == null) return;
-
-    debugPrint('DEBUG: Enhanced SSE event: ${event['type']}, data: $data');
-
-    if (data == '[DONE]') {
-      debugPrint('DEBUG: Enhanced SSE stream finished with [DONE]');
-      streamController.close();
-      return;
-    }
-
-    try {
-      final json = jsonDecode(data) as Map<String, dynamic>;
-      
-      // Handle errors (like OpenWebUI)
-      if (json.containsKey('error')) {
-        final error = json['error'];
-        debugPrint('DEBUG: Enhanced SSE error: $error');
-        streamController.addError('Server error: $error');
-        return;
-      }
-
-      // Handle content streaming (like OpenWebUI's choices processing)
-      if (json.containsKey('choices')) {
-        final choices = json['choices'] as List?;
-        if (choices != null && choices.isNotEmpty) {
-          final choice = choices[0] as Map<String, dynamic>;
-
-          if (choice.containsKey('delta')) {
-            final delta = choice['delta'] as Map<String, dynamic>;
-
-            // Extract content (like OpenWebUI's delta.content)
-            if (delta.containsKey('content')) {
-              final content = delta['content'] as String?;
-              if (content != null && content.isNotEmpty) {
-                debugPrint('DEBUG: Enhanced SSE content chunk: "$content"');
-                streamController.add(content);
-              }
-            }
-
-            // Handle tool calls if present
-            if (delta.containsKey('tool_calls')) {
-              final toolCalls = delta['tool_calls'] as List?;
-              if (toolCalls != null && toolCalls.isNotEmpty) {
-                debugPrint('DEBUG: Enhanced SSE tool calls: $toolCalls');
-                // Could emit special events for tool calls if needed
-              }
-            }
-          }
-
-          // Handle finish reason
-          if (choice.containsKey('finish_reason')) {
-            final finishReason = choice['finish_reason'];
-            if (finishReason != null) {
-              debugPrint('DEBUG: Enhanced SSE finished with reason: $finishReason');
-              streamController.close();
-              return;
-            }
-          }
-        }
-      }
-
-      // Handle other event types (sources, usage, etc.) like OpenWebUI
-      if (json.containsKey('sources')) {
-        debugPrint('DEBUG: Enhanced SSE sources: ${json['sources']}');
-        // Could emit sources events if needed
-      }
-
-      if (json.containsKey('usage')) {
-        debugPrint('DEBUG: Enhanced SSE usage: ${json['usage']}');
-        // Could emit usage events if needed  
-      }
-
-    } catch (e) {
-      debugPrint('DEBUG: Enhanced SSE JSON parse error: $e');
-      // Continue processing - don't fail the entire stream
-    }
-  }
-
-  // Original working SSE streaming implementation
-  void _streamChatCompletionOriginal(
-    Map<String, dynamic> data,
-    StreamController<String> streamController,
-    String messageId,
-  ) async {
-    try {
-      debugPrint('DEBUG: Making SSE request to /api/chat/completions');
-
-      final response = await _dio.post(
-        '/api/chat/completions',
-        data: data,
-        options: Options(
-          responseType: ResponseType.stream,
-          headers: {
-            'Accept': 'text/event-stream',
-            'Cache-Control': 'no-cache',
-            'Connection': 'keep-alive',
-          },
-          receiveTimeout: null,
-        ),
-      );
-
-      debugPrint('DEBUG: SSE response received, status: ${response.statusCode}');
-      debugPrint('DEBUG: SSE response headers: ${response.headers}');
-      debugPrint('DEBUG: SSE response content-type: ${response.headers.value('content-type')}');
-
-      if (response.statusCode != 200) {
-        throw Exception('HTTP ${response.statusCode}: Failed to start streaming');
-      }
-
-      // Process the SSE stream exactly like OpenWebUI frontend
-      final stream = response.data.stream as Stream<List<int>>;
-      String buffer = '';
-      
-      debugPrint('DEBUG: Starting to process SSE stream chunks');
-
-      await for (final chunk in stream) {
-        debugPrint('DEBUG: Received SSE chunk of size: ${chunk.length}');
-        try {
-          // Decode chunk to string
-          final chunkStr = utf8.decode(chunk);
-          buffer += chunkStr;
-
-          // Process complete lines (SSE format)
-          final lines = buffer.split('\n');
-          buffer = lines.removeLast(); // Keep incomplete line in buffer
-
-          for (final line in lines) {
-            final trimmedLine = line.trim();
-            if (trimmedLine.isEmpty) continue;
-
-            debugPrint('DEBUG: SSE line: $trimmedLine');
-
-            if (trimmedLine.startsWith('data: ')) {
-              final jsonStr = trimmedLine.substring(6); // Remove "data: "
-
-              if (jsonStr == '[DONE]') {
-                debugPrint('DEBUG: SSE stream finished with [DONE]');
-                streamController.close();
-                return;
-              }
-
-              try {
-                final json = jsonDecode(jsonStr) as Map<String, dynamic>;
-                debugPrint('DEBUG: SSE JSON: $json');
-
-                // Process exactly like OpenWebUI
-                if (json.containsKey('choices')) {
-                  final choices = json['choices'] as List?;
-                  if (choices != null && choices.isNotEmpty) {
-                    final choice = choices[0] as Map<String, dynamic>;
-
-                    if (choice.containsKey('delta')) {
-                      final delta = choice['delta'] as Map<String, dynamic>;
-
-                      // Handle content streaming (word by word)
-                      if (delta.containsKey('content')) {
-                        final content = delta['content'] as String?;
-                        if (content != null && content.isNotEmpty) {
-                          debugPrint('DEBUG: Adding content chunk: "$content"');
-                          streamController.add(content);
-                        }
-                      }
-
-                      // Handle function calls
-                      if (delta.containsKey('tool_calls')) {
-                        final toolCalls = delta['tool_calls'] as List?;
-                        if (toolCalls != null && toolCalls.isNotEmpty) {
-                          debugPrint('DEBUG: Tool calls received: $toolCalls');
-                          // Handle tool calls if needed
-                        }
-                      }
-                    }
-
-                    // Handle finish reason
-                    if (choice.containsKey('finish_reason')) {
-                      final finishReason = choice['finish_reason'];
-                      if (finishReason != null) {
-                        debugPrint('DEBUG: Stream finished with reason: $finishReason');
-                        streamController.close();
-                        return;
-                      }
-                    }
-                  }
-                } else if (json.containsKey('error')) {
-                  // Handle server errors
-                  final error = json['error'];
-                  debugPrint('DEBUG: SSE error: $error');
-                  streamController.addError('Server error: $error');
-                  return;
-                } else {
-                  debugPrint('DEBUG: Unknown SSE JSON format: $json');
-                }
-              } catch (e) {
-                debugPrint('DEBUG: Error parsing SSE JSON "$jsonStr": $e');
-                // Continue processing other lines
-              }
-            } else if (trimmedLine.startsWith('event: ') ||
-                trimmedLine.startsWith('id: ') ||
-                trimmedLine.startsWith('retry: ')) {
-              // Handle other SSE fields (ignore for now)
-              debugPrint('DEBUG: SSE metadata: $trimmedLine');
-            } else {
-              debugPrint('DEBUG: Unknown SSE line format: $trimmedLine');
-            }
-          }
-        } catch (e) {
-          debugPrint('DEBUG: Error processing SSE chunk: $e');
-          // Continue processing
-        }
-      }
-
-      // Stream ended without [DONE] marker
-      debugPrint('DEBUG: SSE stream ended unexpectedly');
-      streamController.close();
-    } catch (e) {
-      debugPrint('DEBUG: SSE streaming error: $e');
-      streamController.addError(e);
-    }
-  }
 
   // Initialize Socket.IO connection
   Future<void> _initializeSocket() async {

lib/core/services/settings_service.dart

@@ -162,6 +162,11 @@ class SettingsService {
   }
 }
 
+/// Sentinel class to detect when defaultModel parameter is not provided
+class _DefaultValue {
+  const _DefaultValue();
+}
+
 /// Data class for app settings
 class AppSettings {
   final bool reduceMotion;
@@ -189,7 +194,7 @@ class AppSettings {
     bool? highContrast,
     bool? largeText,
     bool? darkMode,
-    String? defaultModel,
+    Object? defaultModel = const _DefaultValue(),
   }) {
     return AppSettings(
       reduceMotion: reduceMotion ?? this.reduceMotion,
@@ -198,7 +203,7 @@ class AppSettings {
       highContrast: highContrast ?? this.highContrast,
       largeText: largeText ?? this.largeText,
       darkMode: darkMode ?? this.darkMode,
-      defaultModel: defaultModel ?? this.defaultModel,
+      defaultModel: defaultModel is _DefaultValue ? this.defaultModel : defaultModel as String?,
     );
   }