// Service worker: precache the app shell, serve network-first with a
// cache fallback so updates show up immediately when online and the app
// still works fully offline. Bump VERSION when the file list changes.

const VERSION = 'picker-v2';
const SHELL = [
  './',
  './index.html',
  './manifest.webmanifest',
  './css/app.css',
  './js/main.js',
  './js/game.js',
  './js/modes.js',
  './js/random.js',
  './js/renderer.js',
  './js/reveals.js',
  './js/input.js',
  './js/audio.js',
  './js/device.js',
  './js/settings.js',
  './js/i18n.js',
  './js/themes.js',
  './js/ui.js',
  './icons/icon.svg',
  './icons/icon-192.png',
  './icons/icon-512.png',
  './icons/icon-maskable-512.png',
  './icons/apple-touch-icon.png',
];
const NETWORK_TIMEOUT_MS = 2500;

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches
      .open(VERSION)
      .then((cache) => cache.addAll(SHELL.map((u) => new Request(u, { cache: 'reload' }))))
      .then(() => self.skipWaiting()),
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches
      .keys()
      .then((keys) => Promise.all(keys.filter((k) => k !== VERSION).map((k) => caches.delete(k))))
      .then(() => self.clients.claim()),
  );
});

self.addEventListener('fetch', (event) => {
  const req = event.request;
  if (req.method !== 'GET' || new URL(req.url).origin !== self.location.origin) return;
  event.respondWith(networkFirst(req, event));
});

async function networkFirst(req, event) {
  const cache = await caches.open(VERSION);
  try {
    const res = await withTimeout(fetch(req), NETWORK_TIMEOUT_MS);
    if (res.ok) event.waitUntil(cache.put(req, res.clone()));
    return res;
  } catch {
    // ignoreSearch so ?debug=1 etc. still resolve offline
    const hit = (await cache.match(req, { ignoreSearch: true })) || (req.mode === 'navigate' && (await cache.match('./index.html')));
    return hit || Response.error();
  }
}

function withTimeout(promise, ms) {
  return new Promise((resolve, reject) => {
    const t = setTimeout(() => reject(new Error('timeout')), ms);
    promise.then(
      (v) => {
        clearTimeout(t);
        resolve(v);
      },
      (e) => {
        clearTimeout(t);
        reject(e);
      },
    );
  });
}