fix: delay image placeholder until text shows

Guard the auto image-loading placeholder so it starts only after a visible text reply and cancel pending timers when the image arrives.

components/chat.tsx

@@ -72,6 +72,7 @@ export function Chat({
   
   // 🆕 跟踪是否正在生成图片（用于占位图显示）
   const [isGeneratingImageFlag, setIsGeneratingImageFlag] = useState(false);
+  const imagePlaceholderTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   
   // 🆕 存储通过 data-appendMessage 添加的消息，避免与 useChat 内部状态冲突
   const [appendedMessages, setAppendedMessages] = useState<ChatMessage[]>([]);
@@ -100,6 +101,16 @@ export function Chat({
     }
   }, [pendingGeneration, initialMessages, completeGeneration, router]);
 
+  // 清理占位图定时器
+  useEffect(() => {
+    return () => {
+      if (imagePlaceholderTimerRef.current) {
+        clearTimeout(imagePlaceholderTimerRef.current);
+        imagePlaceholderTimerRef.current = null;
+      }
+    };
+  }, []);
+
   const { mutate } = useSWRConfig();
 
   // Handle browser back/forward navigation
@@ -303,11 +314,25 @@ export function Chat({
           );
           if (hasGeneratingMarker) {
             console.log("[Chat] 🖼️ Detected GENERATING_IMAGE marker, will show placeholder after delay");
+            const hasDisplayText = messageData.parts?.some((part: any) => {
+              if (part.type !== "text" || !part.text) return false;
+              const cleanedText = part.text.replace(/\n*<!-- GENERATING_IMAGE -->\n*/g, "").trim();
+              return cleanedText.length > 0;
+            });
+            if (!hasDisplayText) {
+              console.log("[Chat] ⚠️ Marker message has no display text, skip image placeholder timer");
+              return;
+            }
             // 🆕 延迟显示占位图，让用户先看到 AI 的文字回复
             // 消息会立即添加到 appendedMessages 并显示，3 秒后再显示动态占位图
-            setTimeout(() => {
+            if (imagePlaceholderTimerRef.current) {
+              clearTimeout(imagePlaceholderTimerRef.current);
+              imagePlaceholderTimerRef.current = null;
+            }
+            imagePlaceholderTimerRef.current = setTimeout(() => {
               console.log("[Chat] 🖼️ Now showing placeholder after 3s delay");
               setIsGeneratingImageFlag(true);
+              imagePlaceholderTimerRef.current = null;
             }, 3000); // 延迟 3 秒，让用户有时间阅读文字
           }
           
@@ -326,6 +351,10 @@ export function Chat({
           
           if (hasImage) {
             console.log("[Chat] 🎉 Image generated, hiding placeholder");
+            if (imagePlaceholderTimerRef.current) {
+              clearTimeout(imagePlaceholderTimerRef.current);
+              imagePlaceholderTimerRef.current = null;
+            }
             setIsGeneratingImageFlag(false);
           }
           

components/messages.tsx

@@ -472,6 +472,14 @@ function PureMessages({
                 (part: any) => part.type === "text" && part.text?.includes("<!-- GENERATING_IMAGE -->")
               )
             );
+            const hasAssistantTextReplyWithContent = messages.some(msg =>
+              msg.role === "assistant" && msg.parts?.some((part: any) => {
+                if (part.type !== "text" || !part.text) return false;
+                if (!part.text.includes("<!-- GENERATING_IMAGE -->")) return false;
+                const cleanedText = part.text.replace(/\n*<!-- GENERATING_IMAGE -->\n*/g, "").trim();
+                return cleanedText.length > 0;
+              })
+            );
             
             if (showVideo) return <QianwenVideoLoading />;
             if (showGemini) return <GeminiImageLoading imageCount={imageCount} />;
@@ -482,7 +490,7 @@ function PureMessages({
             if (isAutoMode && userMessageHasImage) {
               // 🆕 只用 isGeneratingImageFlag 来控制是否显示生图占位图
               // isGeneratingImageFlag 由 chat.tsx 控制：延迟 3 秒后设置为 true，收到图片后设置为 false
-              if (isGeneratingImageFlag) {
+              if (isGeneratingImageFlag && hasAssistantTextReplyWithContent) {
                 return <ImageGenerationLoading imageCount={imageCount} maxImages={6} providerType="alibaba-image" modelName="智能处理" />;
               }
               // 否则显示思考动画（在等待 AI 分析或延迟期间）