email: push new-mail to /email via SSE (IMAP IDLE -> sidecar -> server -> EventSource)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/api/email/email.ts

@@ -10,6 +10,60 @@ export const emailRouter = createRouter();
 
 emailRouter.route('/accounts', accountsRouter);
 
+// ── Real-time: per-user SSE stream of email events (fed by the IMAP IDLE watcher) ──
+const emailSseClients = new Map<string, Set<ReadableStreamDefaultController<Uint8Array>>>();
+
+// Called from the sidecar-message handler when the IDLE watcher saves new mail for a user.
+export function broadcastEmailNew(userEmail: string): void {
+  const set = emailSseClients.get(userEmail);
+  if (!set || set.size === 0) return;
+  const payload = new TextEncoder().encode(`data: ${JSON.stringify({ type: 'new-mail' })}\n\n`);
+  for (const ctrl of set) {
+    try {
+      ctrl.enqueue(payload);
+    } catch {
+      /* dead controller — cleaned up on cancel */
+    }
+  }
+}
+
+// EventSource endpoint (auth via ?token= handled by userMiddleware). The frontend opens this only
+// while on /email, so events stop the moment you navigate away.
+emailRouter.get('/events', (ctx) => {
+  const email = ctx.get('user').email;
+  const enc = new TextEncoder();
+  let controllerRef: ReadableStreamDefaultController<Uint8Array>;
+  let ping: ReturnType<typeof setInterval>;
+  const stream = new ReadableStream<Uint8Array>({
+    start(controller) {
+      controllerRef = controller;
+      let set = emailSseClients.get(email);
+      if (!set) {
+        set = new Set();
+        emailSseClients.set(email, set);
+      }
+      set.add(controller);
+      controller.enqueue(enc.encode('retry: 3000\n\n'));
+      ping = setInterval(() => {
+        try {
+          controller.enqueue(enc.encode(': ping\n\n'));
+        } catch {
+          /* closed */
+        }
+      }, 25_000);
+    },
+    cancel() {
+      clearInterval(ping);
+      const set = emailSseClients.get(email);
+      set?.delete(controllerRef);
+      if (set && set.size === 0) emailSseClients.delete(email);
+    },
+  });
+  return new Response(stream, {
+    headers: { 'Content-Type': 'text/event-stream', 'Cache-Control': 'no-cache', Connection: 'keep-alive' },
+  });
+});
+
 emailRouter.get('/messages', async (ctx) => {
   const email = ctx.get('user').email;
   const page = Number(ctx.req.query('page') ?? '1');