Merge pull request #98 from cogwheel0/feat/chat-archive-assistant-variants

feat(chat): regenerate variants and support

lib/core/models/chat_message.dart

@@ -30,12 +30,40 @@ sealed class ChatMessage with _$ChatMessage {
     @Default(<ChatSourceReference>[])
     List<ChatSourceReference> sources,
     Map<String, dynamic>? usage,
+    // Previous generated versions of this assistant message (OpenWebUI-style)
+    @JsonKey(includeFromJson: false, includeToJson: false)
+    @Default(<ChatMessageVersion>[])
+    List<ChatMessageVersion> versions,
   }) = _ChatMessage;
 
   factory ChatMessage.fromJson(Map<String, dynamic> json) =>
       _$ChatMessageFromJson(json);
 }
 
+@freezed
+abstract class ChatMessageVersion with _$ChatMessageVersion {
+  const factory ChatMessageVersion({
+    required String id,
+    required String content,
+    required DateTime timestamp,
+    String? model,
+    List<Map<String, dynamic>>? files,
+    @JsonKey(
+      name: 'sources',
+      fromJson: _sourceRefsFromJson,
+      toJson: _sourceRefsToJson,
+    )
+    @Default(<ChatSourceReference>[])
+    List<ChatSourceReference> sources,
+    @Default(<String>[]) List<String> followUps,
+    @Default(<ChatCodeExecution>[]) List<ChatCodeExecution> codeExecutions,
+    Map<String, dynamic>? usage,
+  }) = _ChatMessageVersion;
+
+  factory ChatMessageVersion.fromJson(Map<String, dynamic> json) =>
+      _$ChatMessageVersionFromJson(json);
+}
+
 @freezed
 abstract class ChatStatusUpdate with _$ChatStatusUpdate {
   const factory ChatStatusUpdate({

lib/core/services/api_service.dart

@@ -879,10 +879,59 @@ class ApiService {
           }
 
           // Default path: parse message as-is
-          final message = _parseOpenWebUIMessage(
+          var message = _parseOpenWebUIMessage(msgData, historyMsg: historyMsg);
-            msgData,
+
-            historyMsg: historyMsg,
+          // Attach server-persisted variants (siblings) as versions for assistant
+          if (message.role == 'assistant' && historyMessagesMap != null) {
+            try {
+              final parentId = historyMsg?['parentId']?.toString();
+              if (parentId != null && parentId.isNotEmpty) {
+                final parent =
+                    historyMessagesMap[parentId] as Map<String, dynamic>?;
+                final children = parent != null && parent['childrenIds'] is List
+                    ? (parent['childrenIds'] as List)
+                          .map((e) => e.toString())
+                          .toList()
+                    : const <String>[];
+                final versions = <ChatMessageVersion>[];
+
+                for (final cid in children) {
+                  if (cid == message.id) continue; // skip current assistant
+                  final sibling = historyMessagesMap[cid];
+                  if (sibling is Map<String, dynamic>) {
+                    final role = (sibling['role'] ?? '').toString();
+                    if (role != 'assistant') continue;
+                    // Build a ChatMessage from sibling for consistent parsing
+                    final siblingData = Map<String, dynamic>.from(sibling);
+                    siblingData['id'] = cid;
+                    final parsed = _parseOpenWebUIMessage(
+                      siblingData,
+                      historyMsg: sibling,
                     );
+                    versions.add(
+                      ChatMessageVersion(
+                        id: parsed.id,
+                        content: parsed.content,
+                        timestamp: parsed.timestamp,
+                        model: parsed.model,
+                        files: parsed.files,
+                        sources: parsed.sources,
+                        followUps: parsed.followUps,
+                        codeExecutions: parsed.codeExecutions,
+                        usage: parsed.usage,
+                      ),
+                    );
+                  }
+                }
+
+                if (versions.isNotEmpty) {
+                  message = message.copyWith(versions: versions);
+                }
+              }
+            } catch (_) {
+              // Best-effort: ignore variants if parsing fails
+            }
+          }
           messages.add(message);
           if (_traceFullChatParsing) {
             DebugLogger.log(
@@ -1412,14 +1461,19 @@ class ApiService {
     final List<Map<String, dynamic>> messagesArray = [];
     String? currentId;
     String? previousId;
-
+    String? lastUserId;
     for (final msg in messages) {
       final messageId = msg.id;
 
+      // Choose parent id (branch assistants from last user)
+      final parentId = msg.role == 'assistant'
+          ? (lastUserId ?? previousId)
+          : previousId;
+
       // Build message for history.messages map
       messagesMap[messageId] = {
         'id': messageId,
-        'parentId': previousId,
+        'parentId': parentId,
         'childrenIds': [],
         'role': msg.role,
         'content': msg.content,
@@ -1432,14 +1486,14 @@ class ApiService {
       };
 
       // Update parent's childrenIds if there's a previous message
-      if (previousId != null && messagesMap.containsKey(previousId)) {
+      if (parentId != null && messagesMap.containsKey(parentId)) {
-        (messagesMap[previousId]['childrenIds'] as List).add(messageId);
+        (messagesMap[parentId]['childrenIds'] as List).add(messageId);
       }
 
       // Build message for messages array
       messagesArray.add({
         'id': messageId,
-        'parentId': previousId,
+        'parentId': parentId,
         'childrenIds': [],
         'role': msg.role,
         'content': msg.content,
@@ -1453,6 +1507,9 @@ class ApiService {
 
       previousId = messageId;
       currentId = messageId;
+      if (msg.role == 'user') {
+        lastUserId = messageId;
+      }
     }
 
     // Create the chat data structure matching OpenWebUI format exactly
@@ -1509,6 +1566,7 @@ class ApiService {
     final List<Map<String, dynamic>> messagesArray = [];
     String? currentId;
     String? previousId;
+    String? lastUserId;
 
     for (final msg in messages) {
       final messageId = msg.id;
@@ -1517,9 +1575,19 @@ class ApiService {
       // The msg.files array already contains all attachments in the correct format
       final sanitizedFiles = _sanitizeFilesForWebUI(msg.files);
 
+      // Determine parent id: allow explicit parent override via metadata
+      final explicitParent = msg.metadata != null
+          ? (msg.metadata!['parentId']?.toString())
+          : null;
+      // For assistant messages, branch from the last user (OpenWebUI-style)
+      final fallbackParent = msg.role == 'assistant'
+          ? (lastUserId ?? previousId)
+          : previousId;
+      final parentId = explicitParent ?? fallbackParent;
+
       messagesMap[messageId] = {
         'id': messageId,
-        'parentId': previousId,
+        'parentId': parentId,
         'childrenIds': <String>[],
         'role': msg.role,
         'content': msg.content,
@@ -1536,8 +1604,8 @@ class ApiService {
       };
 
       // Update parent's childrenIds
-      if (previousId != null && messagesMap.containsKey(previousId)) {
+      if (parentId != null && messagesMap.containsKey(parentId)) {
-        (messagesMap[previousId]['childrenIds'] as List).add(messageId);
+        (messagesMap[parentId]['childrenIds'] as List).add(messageId);
       }
 
       // Use the same properly formatted files array for messages array
@@ -1545,7 +1613,7 @@ class ApiService {
 
       messagesArray.add({
         'id': messageId,
-        'parentId': previousId,
+        'parentId': parentId,
         'childrenIds': [],
         'role': msg.role,
         'content': msg.content,
@@ -1562,6 +1630,37 @@ class ApiService {
       });
 
       previousId = messageId;
+      if (msg.role == 'user') {
+        lastUserId = messageId;
+      }
+
+      // Server-side persistence of assistant versions (OpenWebUI-style)
+      if (msg.role == 'assistant' && (msg.versions.isNotEmpty)) {
+        final parentForVersions = explicitParent ?? lastUserId ?? previousId;
+        for (final ver in msg.versions) {
+          final vId = ver.id;
+          // Only add if not already present
+          if (!messagesMap.containsKey(vId)) {
+            messagesMap[vId] = {
+              'id': vId,
+              'parentId': parentForVersions,
+              'childrenIds': <String>[],
+              'role': 'assistant',
+              'content': ver.content,
+              'timestamp': ver.timestamp.millisecondsSinceEpoch ~/ 1000,
+              if (ver.model != null) 'model': ver.model,
+              if (ver.model != null) 'modelName': ver.model,
+              'modelIdx': 0,
+              'done': true,
+              if (ver.files != null) 'files': _sanitizeFilesForWebUI(ver.files),
+            };
+            // Link into parent (parentForVersions is always non-null here)
+            if (messagesMap.containsKey(parentForVersions)) {
+              (messagesMap[parentForVersions]['childrenIds'] as List).add(vId);
+            }
+          }
+        }
+      }
       currentId = messageId;
     }
 

lib/features/chat/providers/chat_providers.dart

@@ -494,6 +494,45 @@ class ChatMessagesNotifier extends Notifier<List<ChatMessage>> {
     state = next;
   }
 
+  // Archive the last assistant message's current content as a previous version
+  // and clear it to prepare for regeneration, keeping the same message id.
+  void archiveLastAssistantAsVersion() {
+    if (state.isEmpty) return;
+    final last = state.last;
+    if (last.role != 'assistant') return;
+    // Do not archive if it's already streaming (nothing final to archive)
+    if (last.isStreaming) return;
+
+    final snapshot = ChatMessageVersion(
+      id: last.id,
+      content: last.content,
+      timestamp: last.timestamp,
+      model: last.model,
+      files: last.files == null
+          ? null
+          : List<Map<String, dynamic>>.from(last.files!),
+      sources: List<ChatSourceReference>.from(last.sources),
+      followUps: List<String>.from(last.followUps),
+      codeExecutions: List<ChatCodeExecution>.from(last.codeExecutions),
+      usage: last.usage == null ? null : Map<String, dynamic>.from(last.usage!),
+    );
+
+    final updated = last.copyWith(
+      // Start a fresh stream for the new generation
+      isStreaming: true,
+      content: '',
+      files: null,
+      followUps: const [],
+      codeExecutions: const [],
+      sources: const [],
+      usage: null,
+      versions: [...last.versions, snapshot],
+    );
+
+    state = [...state.sublist(0, state.length - 1), updated];
+    _touchStreamingActivity();
+  }
+
   void appendStatusUpdate(String messageId, ChatStatusUpdate update) {
     final withTimestamp = update.occurredAt == null
         ? update.copyWith(occurredAt: DateTime.now())
@@ -644,10 +683,38 @@ class ChatMessagesNotifier extends Notifier<List<ChatMessage>> {
     final finalized = _finalizeFormatter(lastMessage.id, lastMessage.content);
     final cleaned = _stripStreamingPlaceholders(finalized);
 
-    state = [
+    var updatedLast = lastMessage.copyWith(
-      ...state.sublist(0, state.length - 1),
+      isStreaming: false,
-      lastMessage.copyWith(isStreaming: false, content: cleaned),
+      content: cleaned,
-    ];
+    );
+
+    // Fallback: if there is an immediately previous assistant message
+    // marked as an archived variant and we have no versions yet, attach it
+    // as a version so the UI shows a switcher.
+    if (state.length >= 2 && updatedLast.versions.isEmpty) {
+      final prev = state[state.length - 2];
+      final isArchivedAssistant =
+          prev.role == 'assistant' &&
+          (prev.metadata?['archivedVariant'] == true);
+      if (isArchivedAssistant) {
+        final snapshot = ChatMessageVersion(
+          id: prev.id,
+          content: prev.content,
+          timestamp: prev.timestamp,
+          model: prev.model,
+          files: prev.files,
+          sources: prev.sources,
+          followUps: prev.followUps,
+          codeExecutions: prev.codeExecutions,
+          usage: prev.usage,
+        );
+        updatedLast = updatedLast.copyWith(
+          versions: [...updatedLast.versions, snapshot],
+        );
+      }
+    }
+
+    state = [...state.sublist(0, state.length - 1), updatedLast];
     _messageStream = null;
     _stopRemoteTaskMonitor();
 
@@ -1014,8 +1081,9 @@ Future<Map<String, dynamic>> _buildMessagePayloadWithAttachments({
 Future<void> regenerateMessage(
   dynamic ref,
   String userMessageContent,
-  List<String>? attachments,
+  List<String>? attachments, [
-) async {
+  String? existingAssistantId,
+]) async {
   final reviewerMode = ref.read(reviewerModeProvider);
   final api = ref.read(apiServiceProvider);
   final selectedModel = ref.read(selectedModelProvider);
@@ -1135,13 +1203,42 @@ Future<void> regenerateMessage(
       }
     }
 
-    // Pre-seed assistant skeleton and persist chain
+    // Pre-seed assistant skeleton and persist chain; always use a new id so
+    // server history can branch like OpenWebUI.
     final String assistantMessageId = await _preseedAssistantAndPersist(
       ref,
+      existingAssistantId: null,
       modelId: selectedModel.id,
       systemPrompt: effectiveSystemPrompt,
     );
 
+    // Attach previous assistant as a version snapshot to the new assistant
+    try {
+      final msgs = ref.read(chatMessagesProvider);
+      if (msgs.length >= 2) {
+        final prev = msgs[msgs.length - 2];
+        final last = msgs.last;
+        if (prev.role == 'assistant' && last.id == assistantMessageId) {
+          final snapshot = ChatMessageVersion(
+            id: prev.id,
+            content: prev.content,
+            timestamp: prev.timestamp,
+            model: prev.model,
+            files: prev.files,
+            sources: prev.sources,
+            followUps: prev.followUps,
+            codeExecutions: prev.codeExecutions,
+            usage: prev.usage,
+          );
+          ref
+              .read(chatMessagesProvider.notifier)
+              .updateLastMessageWithFunction(
+                (m) => m.copyWith(versions: [...m.versions, snapshot]),
+              );
+        }
+      }
+    } catch (_) {}
+
     // Feature toggles
     final webSearchEnabled =
         ref.read(webSearchEnabledProvider) &&
@@ -2223,8 +2320,16 @@ final regenerateLastMessageProvider = Provider<Future<void> Function()>((ref) {
 
     if (lastUserMessage == null) return;
 
-    // Remove last assistant message
+    // Mark previous assistant as an archived variant so UI can hide it
-    ref.read(chatMessagesProvider.notifier).removeLastMessage();
+    final notifier = ref.read(chatMessagesProvider.notifier);
+    if (lastAssistantMessage != null) {
+      notifier.updateLastMessageWithFunction((m) {
+        final meta = Map<String, dynamic>.from(m.metadata ?? const {});
+        meta['archivedVariant'] = true;
+        // Keep content/files intact for server persistence
+        return m.copyWith(metadata: meta, isStreaming: false);
+      });
+    }
 
     // If previous assistant was image-only or had images, regenerate images instead of text
     if (lastAssistantHadImages) {

lib/features/chat/views/chat_page.dart

@@ -902,6 +902,13 @@ class _ChatPageState extends ConsumerState<ChatPage> {
                 }
               }
 
+              // Hide archived assistant variants in the linear view
+              final isArchivedVariant =
+                  !isUser && (message.metadata?['archivedVariant'] == true);
+              if (isArchivedVariant) {
+                return const SizedBox.shrink();
+              }
+
               final showFollowUps =
                   !isUser && !hasUserBubbleBelow && !hasAssistantBubbleBelow;
 
@@ -990,8 +997,14 @@ class _ChatPageState extends ConsumerState<ChatPage> {
         return;
       }
 
-      // Remove the assistant message we want to regenerate
+      // Mark previous assistant as archived for UI; keep it for server history
-      ref.read(chatMessagesProvider.notifier).removeLastMessage();
+      ref.read(chatMessagesProvider.notifier).updateLastMessageWithFunction((
+        m,
+      ) {
+        final meta = Map<String, dynamic>.from(m.metadata ?? const {});
+        meta['archivedVariant'] = true;
+        return m.copyWith(metadata: meta, isStreaming: false);
+      });
 
       // Regenerate response for the previous user message (without duplicating it)
       final userMessage = messages[messageIndex - 1];

lib/features/chat/widgets/assistant_message_widget.dart

@@ -70,6 +70,8 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
   bool _allowTypingIndicator = false;
   Timer? _typingGateTimer;
   String _ttsPlainText = '';
+  // Active version index (-1 means current/live content)
+  int _activeVersionIndex = -1;
   // press state handled by shared ChatActionButton
 
   Future<void> _handleFollowUpTap(String suggestion) async {
@@ -140,7 +142,10 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
   }
 
   void _reparseSections() {
-    final raw0 = widget.message.content ?? '';
+    final raw0 = _activeVersionIndex >= 0
+        ? (widget.message.versions[_activeVersionIndex].content as String?) ??
+              ''
+        : widget.message.content ?? '';
     // Strip any leftover placeholders from content before parsing
     const ti = '[TYPING_INDICATOR]';
     const searchBanner = '🔍 Searching the web...';
@@ -633,6 +638,10 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
         widget.showFollowUps &&
         widget.message.followUps.isNotEmpty &&
         !widget.isStreaming;
+    final bool showingVersion = _activeVersionIndex >= 0;
+    final activeFiles = showingVersion
+        ? widget.message.versions[_activeVersionIndex].files
+        : widget.message.files;
     final hasSources = widget.message.sources.isNotEmpty;
 
     return Container(
@@ -657,8 +666,7 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: [
                     // Display attachments - prioritize files array over attachmentIds to avoid duplication
-                    if (widget.message.files != null &&
+                    if (activeFiles != null && activeFiles.isNotEmpty) ...[
-                        widget.message.files!.isNotEmpty) ...[
                       _buildFilesFromArray(),
                       const SizedBox(height: Spacing.md),
                     ] else if (widget.message.attachmentIds != null &&
@@ -729,6 +737,8 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
                         messageId: widget.message.id,
                       ),
                     ],
+
+                    // Version switcher moved inline with action buttons below
                   ],
                 ),
               ),
@@ -896,11 +906,14 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
   }
 
   Widget _buildFilesFromArray() {
-    if (widget.message.files == null || widget.message.files!.isEmpty) {
+    final filesArray = _activeVersionIndex >= 0
+        ? widget.message.versions[_activeVersionIndex].files
+        : widget.message.files;
+    if (filesArray == null || filesArray.isEmpty) {
       return const SizedBox.shrink();
     }
 
-    final allFiles = widget.message.files!;
+    final allFiles = filesArray;
 
     // Separate images and non-image files
     final imageFiles = allFiles
@@ -1077,6 +1090,8 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
     );
   }
 
+  // Deprecated: old in-content version switcher replaced by inline controls with action buttons.
+
   Widget _buildActionButtons() {
     final l10n = AppLocalizations.of(context)!;
     final ttsState = ref.watch(textToSpeechControllerProvider);
@@ -1139,6 +1154,43 @@ class _AssistantMessageWidgetState extends ConsumerState<AssistantMessageWidget>
           label: l10n.copy,
           onTap: widget.onCopy,
         ),
+        if (widget.message.versions.isNotEmpty && !widget.isStreaming) ...[
+          // Inline version toggle: Prev [1/n] Next
+          ChatActionButton(
+            icon: Icons.chevron_left,
+            label: 'Prev',
+            onTap: () {
+              setState(() {
+                if (_activeVersionIndex < 0) {
+                  _activeVersionIndex = widget.message.versions.length - 1;
+                } else if (_activeVersionIndex > 0) {
+                  _activeVersionIndex -= 1;
+                }
+                _reparseSections();
+              });
+            },
+          ),
+          ConduitChip(
+            label:
+                '${_activeVersionIndex < 0 ? (widget.message.versions.length + 1) : (_activeVersionIndex + 1)}/${widget.message.versions.length + 1}',
+            isCompact: true,
+          ),
+          ChatActionButton(
+            icon: Icons.chevron_right,
+            label: 'Next',
+            onTap: () {
+              setState(() {
+                if (_activeVersionIndex < 0) return; // already live
+                if (_activeVersionIndex < widget.message.versions.length - 1) {
+                  _activeVersionIndex += 1;
+                } else {
+                  _activeVersionIndex = -1; // move to live
+                }
+                _reparseSections();
+              });
+            },
+          ),
+        ],
         if (isErrorMessage) ...[
           _buildActionButton(
             icon: Platform.isIOS