perf(realtime): debounce typing start/stop events

web/src/components/MessageComposer.tsx

@@ -109,6 +109,8 @@ export function MessageComposer() {
   const recordingStateRef = useRef<RecordingState>("idle");
   const lastEditingMessageIdRef = useRef<number | null>(null);
   const prevActiveChatIdRef = useRef<number | null>(null);
+  const typingActiveRef = useRef(false);
+  const typingStopTimerRef = useRef<number | null>(null);
 
   const [isUploading, setIsUploading] = useState(false);
   const [uploadProgress, setUploadProgress] = useState(0);
@@ -247,6 +249,9 @@ export function MessageComposer() {
       if (pointerUpHandlerRef.current) {
         window.removeEventListener("pointerup", pointerUpHandlerRef.current);
       }
+      if (typingStopTimerRef.current !== null) {
+        window.clearTimeout(typingStopTimerRef.current);
+      }
     };
   }, [previewUrl]);
 
@@ -261,6 +266,11 @@ export function MessageComposer() {
     if (prev && prev !== activeChatId) {
       const ws = getWs();
       ws?.send(JSON.stringify({ event: "typing_stop", payload: { chat_id: prev } }));
+      typingActiveRef.current = false;
+      if (typingStopTimerRef.current !== null) {
+        window.clearTimeout(typingStopTimerRef.current);
+        typingStopTimerRef.current = null;
+      }
     }
     prevActiveChatIdRef.current = activeChatId;
   }, [activeChatId]);
@@ -333,6 +343,46 @@ export function MessageComposer() {
     ws?.send(JSON.stringify({ event: eventName, payload: { chat_id: activeChatId } }));
   }
 
+  function emitTypingStopIfActive() {
+    if (!activeChatId) {
+      return;
+    }
+    if (typingStopTimerRef.current !== null) {
+      window.clearTimeout(typingStopTimerRef.current);
+      typingStopTimerRef.current = null;
+    }
+    if (typingActiveRef.current) {
+      sendRealtimeChatEvent("typing_stop");
+      typingActiveRef.current = false;
+    }
+  }
+
+  function syncTypingForText(nextText: string) {
+    if (!activeChatId) {
+      return;
+    }
+    const hasText = nextText.trim().length > 0;
+    if (!hasText) {
+      emitTypingStopIfActive();
+      return;
+    }
+    if (!typingActiveRef.current) {
+      sendRealtimeChatEvent("typing_start");
+      typingActiveRef.current = true;
+    }
+    if (typingStopTimerRef.current !== null) {
+      window.clearTimeout(typingStopTimerRef.current);
+    }
+    typingStopTimerRef.current = window.setTimeout(() => {
+      if (!typingActiveRef.current) {
+        return;
+      }
+      sendRealtimeChatEvent("typing_stop");
+      typingActiveRef.current = false;
+      typingStopTimerRef.current = null;
+    }, 2500);
+  }
+
   async function handleSend() {
     if (!activeChatId || !text.trim() || !me || !canSendInActiveChat) {
       return;
@@ -373,7 +423,7 @@ export function MessageComposer() {
       setText("");
       clearDraft(activeChatId);
       setReplyToMessage(activeChatId, null);
-      sendRealtimeChatEvent("typing_stop");
+      emitTypingStopIfActive();
     } catch {
       removeOptimisticMessage(activeChatId, clientMessageId);
       setUploadError("Message send failed. Please try again.");
@@ -644,7 +694,7 @@ export function MessageComposer() {
       recordingStartedAtRef.current = Date.now();
       setRecordSeconds(0);
       setRecordingState("recording");
-      sendRealtimeChatEvent("typing_stop");
+      emitTypingStopIfActive();
       sendRealtimeChatEvent("recording_voice_start");
       return true;
     } catch {
@@ -1304,13 +1354,11 @@ export function MessageComposer() {
             setText(next);
             if (activeChatId) {
               setDraft(activeChatId, next);
-              sendRealtimeChatEvent(next.trim().length > 0 ? "typing_start" : "typing_stop");
+              syncTypingForText(next);
             }
           }}
           onBlur={() => {
-            if (activeChatId) {
+            emitTypingStopIfActive();
-              sendRealtimeChatEvent("typing_stop");
-            }
           }}
         />