Background NWC: the worker now answers — and pays — from the pouch

The no-tap half of background wallet-connect. The push payload carries
the (encrypted, client-signed) request event; a bundled service-worker
responder (src/sw-nwc.js -> nwc-respond.js) finds the matching pouch in
IndexedDB, decrypts with the connection's service key, and answers
get_info/get_balance/list_transactions from pouch state. pay_invoice
pays through the swap bridge with an ArkManager running over the
pouch's chain-6 key window (one HTLC lock, one HTTP swap), enforcing
per-payment and daily budgets from the pouch's own spend log, checking
the notifier's /answered endpoint so it never double-pays or shouts
over an open device, and persisting the swap before handing it off so
the app can refund a crashed flight. Anything it can't handle falls
back to the wake-the-user notification.

The notifier grows /publish (verified 23195s only, rate-limited) as the
worker's reply pipe and /answered for race avoidance. The app gains
pouch funding (mailbox-less arkoor self-send whose recipient bytes we
keep), emptying, spend/budget reconciliation on open, and refund
recovery with the pouch's own keys.

Co-Authored-By: Claude Fable 5 <[email protected]>

1 files changed, 49 insertions, 0 deletions

diff --git a/src/sw-nwc.js b/src/sw-nwc.js
new file mode 100644
index 0000000..db57b99
--- /dev/null
+++ b/src/sw-nwc.js
@@ -0,0 +1,49 @@
+// Service-worker side of background NWC. Bundled by build.js and appended to
+// the generated sw.js, replacing the notify-only push handler: a push now
+// first tries to ANSWER the request from the pouch (see nwc-respond.js), and
+// only falls back to the wake-the-user notification when it can't.
+
+import { respondFromPouch } from './nwc-respond.js';
+
+const NOTIFIER = 'https://nwcpush.coinos.io';
+
+self.addEventListener('push', (e) => {
+  let data = {};
+  try { data = e.data ? e.data.json() : {}; } catch (_) {}
+  if (data.type !== 'nwc') return;
+  e.waitUntil((async () => {
+    // An open window handles requests itself with full wallet state — nudge
+    // it and stay out of the way.
+    const clients = await self.clients.matchAll({ type: 'window', includeUncontrolled: true });
+    if (clients.length) {
+      for (const c of clients) c.postMessage({ type: 'nwc-wake', servicePubkey: data.servicePubkey });
+      return;
+    }
+    let handled = false;
+    try {
+      handled = await respondFromPouch(data, {
+        notifier: NOTIFIER,
+        log: (m) => console.log('[sw-nwc]', m),
+      });
+    } catch (err) {
+      console.warn('[sw-nwc] auto-answer failed:', err && err.message);
+    }
+    if (handled) return;
+    await self.registration.showNotification('Payment request', {
+      body: 'An app is asking your wallet to pay. Open Hal to approve.',
+      icon: 'icon-192.png', badge: 'icon-192.png',
+      tag: 'nwc-' + (data.servicePubkey || 'req'), renotify: false,
+      data: { url: './' },
+    });
+  })());
+});
+
+self.addEventListener('notificationclick', (e) => {
+  e.notification.close();
+  e.waitUntil((async () => {
+    const all = await self.clients.matchAll({ type: 'window', includeUncontrolled: true });
+    const open = all.find((c) => 'focus' in c);
+    if (open) return open.focus();
+    if (self.clients.openWindow) return self.clients.openWindow('./');
+  })());
+});