// hidden11 service worker.
//
// Scope is deliberately narrow: it exists to deliver the daily reminder, not to
// cache the app. The push messages are sent WITHOUT a payload (the sender only
// needs a VAPID header, no content encryption), so the notification copy is
// written into the Cache API when the user subscribes and read back here — a
// service worker cannot reach localStorage.

const MESSAGE_CACHE = "hidden11-push";
const MESSAGE_KEY = "/__push-message";

const FALLBACK = {
  title: "hidden11",
  body: "Today's hidden XI is live.",
  url: "/",
};

async function reminderMessage() {
  try {
    const cache = await caches.open(MESSAGE_CACHE);
    const stored = await cache.match(MESSAGE_KEY);
    if (!stored) return FALLBACK;
    const data = await stored.json();
    return {
      title: data.title || FALLBACK.title,
      body: data.body || FALLBACK.body,
      url: data.url || FALLBACK.url,
    };
  } catch {
    return FALLBACK;
  }
}

self.addEventListener("install", () => {
  self.skipWaiting();
});

self.addEventListener("activate", (event) => {
  event.waitUntil(self.clients.claim());
});

self.addEventListener("push", (event) => {
  event.waitUntil(
    (async () => {
      const message = await reminderMessage();
      await self.registration.showNotification(message.title, {
        body: message.body,
        icon: "/icon-192.png",
        badge: "/icon-192.png",
        tag: "hidden11-daily",
        renotify: true,
        data: { url: message.url },
      });
    })(),
  );
});

self.addEventListener("notificationclick", (event) => {
  event.notification.close();
  const target = event.notification.data?.url || FALLBACK.url;

  event.waitUntil(
    (async () => {
      const allClients = await self.clients.matchAll({ type: "window", includeUncontrolled: true });
      const existing = allClients.find((client) => client.url.includes(self.location.origin));
      if (existing) {
        await existing.focus();
        if ("navigate" in existing) await existing.navigate(target);
        return;
      }
      await self.clients.openWindow(target);
    })(),
  );
});