Stream each task's transcript over its own SSE; keep session note order

web/src/state.ts

@@ -1,4 +1,4 @@
-import { get, type AgentSession, type ByreEvent, type InboxItem, type Project, type Task, type User } from "./api.js";
+import { get, subscribe, type AgentSession, type ByreEvent, type InboxItem, type Project, type Task, type User } from "./api.js";
 
 export type Topic = "me" | "projects" | "tasks" | "sessions" | "inbox" | "selection" | "transcript" | "stream" | "connection" | "event";
 
@@ -87,7 +87,9 @@ export async function loadInbox(): Promise<void> {
   notify("inbox");
 }
 
-let liveDuringLoad: ByreEvent[] | undefined;
+let closeTaskStream: (() => void) | undefined;
+let taskBuffer: ByreEvent[] = [];
+let taskFlush = 0;
 
 const visitsKey = "byre.visits";
 
@@ -102,33 +104,48 @@ function markVisited(taskId: string | undefined): void {
   localStorage.setItem(visitsKey, JSON.stringify({ ...lastVisits(), [taskId]: Date.now() }));
 }
 
-export async function selectTask(taskId: string | undefined): Promise<void> {
+export function selectTask(taskId: string | undefined): void {
   markVisited(state.selectedTaskId);
   markVisited(taskId);
+  closeTaskStream?.();
+  closeTaskStream = undefined;
+  clearTimeout(taskFlush);
+  taskFlush = 0;
+  taskBuffer = [];
   state.selectedTaskId = taskId;
   state.transcript = [];
   state.lastTranscriptSeq = 0;
-  liveDuringLoad = undefined;
   notify("selection");
 
   if (!taskId) {
     return;
   }
 
-  const held: ByreEvent[] = [];
-  liveDuringLoad = held;
-  for (;;) {
-    const page = await get("/api/tasks/{taskId}/events", { path: { taskId }, query: { after: state.lastTranscriptSeq, limit: 1000 } });
-    if (state.selectedTaskId !== taskId || liveDuringLoad !== held) {
-      return;
-    }
-    appendTranscript(page);
-    if (page.length < 1000) {
-      break;
-    }
+  closeTaskStream = subscribe(0, taskId, queueTaskEvent, () => undefined);
+}
+
+function queueTaskEvent(ev: ByreEvent): void {
+  taskBuffer.push(ev);
+  if (!taskFlush) {
+    taskFlush = setTimeout(flushTaskEvents, 0);
   }
-  liveDuringLoad = undefined;
-  appendTranscript(held);
+}
+
+function flushTaskEvents(): void {
+  const events = taskBuffer;
+  taskBuffer = [];
+  taskFlush = 0;
+  let stored: ByreEvent[] = [];
+  for (const ev of events) {
+    if (ev.seq !== 0) {
+      stored.push(ev);
+      continue;
+    }
+    appendTranscript(stored);
+    stored = [];
+    notify("stream", ev);
+  }
+  appendTranscript(stored);
 }
 
 function appendTranscript(events: ByreEvent[]): void {
@@ -143,21 +160,10 @@ function appendTranscript(events: ByreEvent[]): void {
 
 export function handleEvent(ev: ByreEvent): void {
   if (ev.seq === 0) {
-    if (ev.task_id && ev.task_id === state.selectedTaskId && !liveDuringLoad) {
-      notify("stream", ev);
-    }
     notify("event", ev);
     return;
   }
 
-  if (ev.task_id && ev.task_id === state.selectedTaskId) {
-    if (liveDuringLoad) {
-      liveDuringLoad.push(ev);
-    } else {
-      appendTranscript([ev]);
-    }
-  }
-
   switch (ev.kind) {
     case "user.updated":
       if (ev.payload["login"] === state.me?.login) {