// Network-first service worker: always fresh when online, app shell still opens offline.
const CACHE = 'whattodo-v2';
const SHELL = [
  './', 'index.html', 'style.css', 'app.js', 'manifest.webmanifest',
  'icons/icon.svg', 'icons/icon-192.png', 'icons/icon-512.png',
];

self.addEventListener('install', (event) => {
  event.waitUntil(caches.open(CACHE).then((c) => c.addAll(SHELL)).then(() => 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;
  const url = new URL(req.url);
  if (req.method !== 'GET' || url.origin !== self.location.origin || url.pathname.includes('/api/')) return;
  event.respondWith(
    fetch(req)
      .then((res) => {
        if (res.ok) {
          const copy = res.clone();
          caches.open(CACHE).then((c) => c.put(req, copy));
        }
        return res;
      })
      .catch(() => caches.match(req).then((hit) => hit || caches.match('index.html'))),
  );
});