sw.js

/* Chained Timers — Service Worker */
const CACHE = 'chained-timers-v1.4.24';
const ASSETS = [
  './',
  './index.html',
  './css/styles.css',
  './css/fonts.css',
  './js/app.js',
  './manifest.webmanifest',
  './icons/icon.svg',
  './icons/icon-192.png',
  './icons/icon-512.png',
  './icons/icon-maskable-192.png',
  './icons/icon-maskable-512.png',
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE).then(c => c.addAll(ASSETS).catch(() => {}))
  );
  self.skipWaiting();
});

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

self.addEventListener('fetch', (event) => {
  const req = event.request;
  if (req.method !== 'GET') return;

  // network-first for HTML so updates roll out without manual refresh
  const url = new URL(req.url);
  const isHTML = req.mode === 'navigate' || (req.headers.get('accept') || '').includes('text/html');

  if (isHTML) {
    event.respondWith(
      fetch(req).then(res => {
        const copy = res.clone();
        caches.open(CACHE).then(c => c.put(req, copy));
        return res;
      }).catch(() => caches.match(req).then(r => r || caches.match('./index.html')))
    );
    return;
  }

  // cache-first for static assets
  event.respondWith(
    caches.match(req).then(cached => cached || fetch(req).then(res => {
      if (res.ok && url.origin === location.origin) {
        const copy = res.clone();
        caches.open(CACHE).then(c => c.put(req, copy));
      }
      return res;
    }).catch(() => cached))
  );
});

self.addEventListener('notificationclick', (event) => {
  event.notification.close();
  event.waitUntil(
    self.clients.matchAll({ type: 'window' }).then(list => {
      for (const c of list) { if ('focus' in c) return c.focus(); }
      if (self.clients.openWindow) return self.clients.openWindow('./');
    })
  );
});