:lightning: optimize chat streaming

src/main/ipcHandlers.ts

@@ -135,11 +135,27 @@ export function registerIpcHandlers(): void {
   ipcMain.handle('ai:streamMessage', async (event, payload: AIPayload) => {
     try {
       const storyBibleContent = (await readStoryBibleFile()) ?? undefined
+
+      let pending = ''
+      let flushTimer: ReturnType<typeof setTimeout> | null = null
+
+      const flush = (): void => {
+        if (flushTimer) { clearTimeout(flushTimer); flushTimer = null }
+        if (pending && !event.sender.isDestroyed()) {
+          event.sender.send('ai:chunk', pending)
+          pending = ''
+        }
+      }
+
       await streamMessage(payload, storyBibleContent, (chunk: string) => {
-        if (!event.sender.isDestroyed()) {
-          event.sender.send('ai:chunk', chunk)
+        pending += chunk
+        if (!flushTimer) {
+          flushTimer = setTimeout(flush, 30)
         }
       })
+
+      flush()
+
       if (!event.sender.isDestroyed()) {
         event.sender.send('ai:done')
       }

src/renderer/components/AIChat/ChatMessageItem.tsx

@@ -1,4 +1,4 @@
-import { useMemo } from 'react'
+import { useMemo, memo } from 'react'
 import { marked } from 'marked'
 import DOMPurify from 'dompurify'
 import type { ChatMessage, TextAnnotation } from '../../types/editor'
@@ -30,7 +30,7 @@ interface Props {
   linkedAnnotations?: TextAnnotation[]
 }
 
-export function ChatMessageItem({ message, linkedAnnotations }: Props): JSX.Element {
+function ChatMessageItemInner({ message, linkedAnnotations }: Props): JSX.Element {
   const { activeFilePath, markSaved } = useEditorStore()
 
   const html = useMemo(() => {
@@ -123,3 +123,13 @@ export function ChatMessageItem({ message, linkedAnnotations }: Props): JSX.Elem
     </div>
   )
 }
+
+function areEqual(prev: Props, next: Props): boolean {
+  if (prev.message.content !== next.message.content) return false
+  if (prev.message.id !== next.message.id) return false
+  const prevIds = prev.linkedAnnotations?.map(a => a.id).join(',') ?? ''
+  const nextIds = next.linkedAnnotations?.map(a => a.id).join(',') ?? ''
+  return prevIds === nextIds
+}
+
+export const ChatMessageItem = memo(ChatMessageItemInner, areEqual)

src/renderer/components/AIChat/ChatPanel.tsx

@@ -50,6 +50,7 @@ export function ChatPanel(): JSX.Element {
   const [pendingAttachmentCount, setPendingAttachmentCount] = useState(0)
   const [feedbackNotice, setFeedbackNotice] = useState<string | null>(null)
   const scrollRef = useRef<HTMLDivElement>(null)
+  const scrollRafRef = useRef<number | null>(null)
   const prevAnnotationCountRef = useRef(annotations.length)
 
   // Collapse history when switching files
@@ -119,12 +120,14 @@ export function ChatPanel(): JSX.Element {
     }
   }
 
-  // Auto-scroll to bottom when new content arrives
+  // Auto-scroll to bottom when new content arrives (coalesced to one scroll per animation frame)
   useEffect(() => {
-    const el = scrollRef.current
-    if (el) {
-      el.scrollTop = el.scrollHeight
-    }
+    if (scrollRafRef.current !== null) return
+    scrollRafRef.current = requestAnimationFrame(() => {
+      scrollRafRef.current = null
+      const el = scrollRef.current
+      if (el) el.scrollTop = el.scrollHeight
+    })
   }, [chatHistory])
 
   const hasFile = Boolean(activeFilePath)

src/renderer/store/editorStore.ts

@@ -256,17 +256,24 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       if (last?.role === 'assistant') {
         history[history.length - 1] = { ...last, content: last.content + chunk }
       }
-      if (!s.activeFilePath) return { chatHistory: history }
-      const activeId = s.activeSessionIdByFile[s.activeFilePath]
-      const sessions = (s.chatSessionsByFile[s.activeFilePath] ?? []).map(sess =>
-        sess.id === activeId ? { ...sess, messages: history } : sess
-      )
-      return { chatHistory: history, chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: sessions } }
+      return { chatHistory: history }
     })
   },
 
   setAILoading: (isAILoading) => {
-    set({ isAILoading })
+    set((s) => {
+      if (isAILoading) return { isAILoading }
+      // Sync the completed chatHistory into chatSessionsByFile once at stream end
+      if (!s.activeFilePath) return { isAILoading }
+      const activeId = s.activeSessionIdByFile[s.activeFilePath]
+      const sessions = (s.chatSessionsByFile[s.activeFilePath] ?? []).map(sess =>
+        sess.id === activeId ? { ...sess, messages: s.chatHistory } : sess
+      )
+      return {
+        isAILoading,
+        chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: sessions }
+      }
+    })
     // When AI finishes, persist the completed chat history
     if (!isAILoading) {
       scheduleSave(() => {