feat(chat): stop active llm responses

backend/internal/api/handlers.go

@@ -449,6 +449,32 @@ func (a *API) GetChatStream(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (a *API) StopChatGeneration(w http.ResponseWriter, r *http.Request) {
+	log := a.logger.WithField("handler", "StopChatGenerationHandler")
+
+	// Parse Chat ID
+	rawChatID := r.PathValue("chatId")
+	if rawChatID == "" {
+		log.Error("missing chat ID parameter")
+		http.Error(w, "Chat ID is required", http.StatusBadRequest)
+		return
+	}
+	chatID, err := uuid.Parse(rawChatID)
+	if err != nil {
+		log.WithError(err).Error("invalid chat ID format")
+		http.Error(w, "Invalid chat ID format", http.StatusBadRequest)
+		return
+	}
+
+	// Stop Generation
+	if !a.generationManager.stop(chatID) {
+		http.Error(w, "Chat generation is not active", http.StatusNotFound)
+		return
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}
+
 func (a *API) PostChatMessage(w http.ResponseWriter, r *http.Request) {
 	log := a.logger.WithField("handler", "PostChatMessageHandler")
 
@@ -563,7 +589,7 @@ func (a *API) startMessageGeneration(chatID uuid.UUID, chatModel, userMessage st
 
 func (a *API) runMessageGeneration(apiClient *client.Client, chat *store.Chat, assistantMsg *store.Message, chatModel string, gen *generation) {
 	// Create Generation Context
-	ctx, cancel := context.WithTimeout(context.Background(), time.Minute*5)
+	ctx, cancel := context.WithTimeout(gen.ctx, time.Minute*5)
 	defer cancel()
 
 	// Send Message
@@ -593,15 +619,37 @@ func (a *API) runMessageGeneration(apiClient *client.Client, chat *store.Chat, a
 
 		return nil
 	}); err != nil {
-		assistantMsg.Status = store.MessageStatusFailed
+		// Handle Stopped Generation
+		if errors.Is(gen.ctx.Err(), context.Canceled) {
+			assistantMsg.Status = store.MessageStatusStopped
+			if saveErr := a.store.SaveChatMessage(assistantMsg); saveErr != nil {
+				a.logger.WithError(saveErr).WithField("chat_id", chat.ID).Error("failed to save stopped assistant message")
+			}
+			gen.broadcast(&MessageChunk{AssistantMessage: assistantMsg})
+			return
+		}
+
+		// Handle Error Generation
+		assistantMsg.Status = store.MessageStatusError
 		if saveErr := a.store.SaveChatMessage(assistantMsg); saveErr != nil {
-			a.logger.WithError(saveErr).WithField("chat_id", chat.ID).Error("failed to save failed assistant message")
+			a.logger.WithError(saveErr).WithField("chat_id", chat.ID).Error("failed to save errored assistant message")
 		}
 		gen.broadcast(&MessageChunk{AssistantMessage: assistantMsg})
 		a.logger.WithError(err).WithField("chat_id", chat.ID).Error("failed to generate text stream")
 		return
 	}
 
+	// Handle Stopped Generation
+	if errors.Is(gen.ctx.Err(), context.Canceled) {
+		assistantMsg.Status = store.MessageStatusStopped
+		if err := a.store.SaveChatMessage(assistantMsg); err != nil {
+			a.logger.WithError(err).WithField("chat_id", chat.ID).Error("failed to save stopped assistant message")
+			return
+		}
+		gen.broadcast(&MessageChunk{AssistantMessage: assistantMsg})
+		return
+	}
+
 	// Summarize & Update Chat Title
 	if chat.Title == "" {
 		var err error