Final dev

frontend/src/app/user/my-courses/page.tsx

@@ -175,7 +175,8 @@ function MyCoursesContent() {
     return () => {
       cancelled = true;
     };
-  }, [authLoading, isAuthenticated]); // Removed selectedId to prevent infinite loop
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [authLoading, isAuthenticated]); // selectedId intentionally omitted to prevent infinite loop
 
   // Load recommended courses immediately on mount
   useEffect(() => {

frontend/src/app/user/my-quizzes/[quizId]/play/page.tsx

@@ -227,7 +227,8 @@ export default function QuizPlayPage({ params }: PageProps) {
     };
     load();
     return () => { cancelled = true; };
-  }, [quizId]);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [quizId]); // answerDisplayMode intentionally omitted
 
   const handleTimeUp = useCallback(() => {
     // Prevent duplicate execution
@@ -269,7 +270,8 @@ export default function QuizPlayPage({ params }: PageProps) {
       // Reset flag after transition
       isProcessingTimeout.current = false;
     }, 1500);
-  }, [quiz, currentIndex, answers, timePerQuestion]);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [quiz, currentIndex, answers, timePerQuestion]); // handleSubmit intentionally omitted to avoid circular dependency
 
   // Timer countdown
   useEffect(() => {

frontend/src/app/user/ranking/page.tsx

@@ -11,7 +11,7 @@ export default function RankingPage() {
   const handleLogout = useCallback(() => router.push('/auth/login'), [router]);
   const { user, dashboardData, loading } = useDashboard(handleLogout);
 
-  const users = dashboardData?.info?.user_top_rank || [];
+  const users = useMemo(() => dashboardData?.info?.user_top_rank || [], [dashboardData]);
 
   // Find competitors (user + 1 above + 1 below)
   const competitors = useMemo(() => {

frontend/src/app/user/tracking/page.tsx

@@ -44,9 +44,11 @@ function TrackingInner() {
       if (resp.status === 200 && Array.isArray(resp.data?.items)) {
         const items = resp.data.items as GenerationItem[];
         items.sort((a, b) => {
-          if (!a.updated_at) return 1;
-          if (!b.updated_at) return -1;
-          return new Date(b.updated_at).getTime() - new Date(a.updated_at).getTime();
+          const aTime = a.updated_at || a.last_updated;
+          const bTime = b.updated_at || b.last_updated;
+          if (!aTime) return 1;
+          if (!bTime) return -1;
+          return new Date(bTime).getTime() - new Date(aTime).getTime();
         });
         setCourseItems(items);
       } else if (resp.status === 401) {

frontend/src/components/user/chatbot/LessonChatbot.tsx

@@ -23,6 +23,7 @@ export default function LessonChatbot({ lessonId, courseId }: ChatbotProps) {
   const [inputValue, setInputValue] = useState('');
   const [isLoading, setIsLoading] = useState(false);
   const [pendingChatId, setPendingChatId] = useState<string | null>(null);
+  const [pollStartTime, setPollStartTime] = useState<number | null>(null);
 
   const messagesEndRef = useRef<HTMLDivElement>(null);
   const lastActivityRef = useRef<number>(Date.now());
@@ -73,8 +74,27 @@ export default function LessonChatbot({ lessonId, courseId }: ChatbotProps) {
   useEffect(() => {
     if (!pendingChatId) return;
 
+    const POLLING_TIMEOUT = 180000; // 3 minutes (longer timeout for when course generation is running)
+
     const pollAnswer = async () => {
       try {
+        // Check timeout
+        if (pollStartTime && Date.now() - pollStartTime > POLLING_TIMEOUT) {
+          setMessages(prev => [
+            ...prev,
+            {
+              id: pendingChatId,
+              role: 'assistant',
+              content: 'Xin lỗi, hệ thống đang bận xử lý. Câu hỏi này có thể mất vài phút để trả lời. Bạn vui lòng thử lại sau nhé! 🙏',
+              timestamp: new Date(),
+            },
+          ]);
+          setPendingChatId(null);
+          setIsLoading(false);
+          setPollStartTime(null);
+          return;
+        }
+
         const response = await chatbotApi.getAnswer(pendingChatId);
         const data = response.data;
 
@@ -90,6 +110,7 @@ export default function LessonChatbot({ lessonId, courseId }: ChatbotProps) {
           ]);
           setPendingChatId(null);
           setIsLoading(false);
+          setPollStartTime(null);
         } else if (data.status === 500) {
           const errorMessage = data.message || 'Xin lỗi, mình gặp lỗi khi xử lý câu hỏi của bạn. Bạn có thể thử lại không?';
           setMessages(prev => [
@@ -103,11 +124,21 @@ export default function LessonChatbot({ lessonId, courseId }: ChatbotProps) {
           ]);
           setPendingChatId(null);
           setIsLoading(false);
+          setPollStartTime(null);
+        }
+        // For 202 (processing) or 404 (not yet created), continue polling
+      } catch (error: unknown) {
+        // If 404, treat as still processing (Lambda hasn't created record yet)
+        if (error && typeof error === 'object' && 'response' in error) {
+          const err = error as { response?: { status?: number } };
+          if (err.response?.status === 404) {
+            return; // Continue polling
+          }
         }
-      } catch (error) {
         console.error('Error polling answer:', error);
         setPendingChatId(null);
         setIsLoading(false);
+        setPollStartTime(null);
       }
     };
 
@@ -116,10 +147,11 @@ export default function LessonChatbot({ lessonId, courseId }: ChatbotProps) {
 
     return () => {
       if (pollingIntervalRef.current) {
+    setPollStartTime(Date.now()); // Start timeout timer
         clearInterval(pollingIntervalRef.current);
       }
     };
-  }, [pendingChatId]);
+  }, [pendingChatId, pollStartTime]);
 
   useEffect(() => {
     messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });