feat(chat): prevent auto-scroll unless message sent

src/components/Chat.tsx

@@ -7,11 +7,12 @@ import MessageBoxLoading from './MessageBoxLoading';
 import { useChat } from '@/lib/hooks/useChat';
 
 const Chat = () => {
-  const { sections, chatTurns, loading, messageAppeared } = useChat();
+  const { sections, loading, messageAppeared, messages } = useChat();
 
   const [dividerWidth, setDividerWidth] = useState(0);
   const dividerRef = useRef<HTMLDivElement | null>(null);
   const messageEnd = useRef<HTMLDivElement | null>(null);
+  const lastScrolledRef = useRef<number>(0);
 
   useEffect(() => {
     const updateDividerWidth = () => {
@@ -22,35 +23,40 @@ const Chat = () => {
 
     updateDividerWidth();
 
+    const resizeObserver = new ResizeObserver(() => {
+      updateDividerWidth();
+    });
+
+    const currentRef = dividerRef.current;
+    if (currentRef) {
+      resizeObserver.observe(currentRef);
+    }
+
     window.addEventListener('resize', updateDividerWidth);
 
     return () => {
+      if (currentRef) {
+        resizeObserver.unobserve(currentRef);
+      }
+      resizeObserver.disconnect();
       window.removeEventListener('resize', updateDividerWidth);
     };
-  }, []);
+  }, [sections.length]);
 
   useEffect(() => {
     const scroll = () => {
       messageEnd.current?.scrollIntoView({ behavior: 'auto' });
     };
 
-    if (chatTurns.length === 1) {
-      document.title = `${chatTurns[0].content.substring(0, 30)} - Perplexica`;
+    if (messages.length === 1) {
+      document.title = `${messages[0].query.substring(0, 30)} - Perplexica`;
     }
 
-    const messageEndBottom =
-      messageEnd.current?.getBoundingClientRect().bottom ?? 0;
-
-    const distanceFromMessageEnd = window.innerHeight - messageEndBottom;
-
-    if (distanceFromMessageEnd >= -100) {
+    if (sections.length > lastScrolledRef.current) {
       scroll();
+      lastScrolledRef.current = sections.length;
     }
-
-    if (chatTurns[chatTurns.length - 1]?.role === 'user') {
-      scroll();
-    }
-  }, [chatTurns]);
+  }, [messages]);
 
   return (
     <div className="flex flex-col space-y-6 pt-8 pb-44 lg:pb-32 sm:mx-4 md:mx-8">
@@ -58,7 +64,7 @@ const Chat = () => {
         const isLast = i === sections.length - 1;
 
         return (
-          <Fragment key={section.userMessage.messageId}>
+          <Fragment key={section.message.messageId}>
             <MessageBox
               section={section}
               sectionIndex={i}