const CACHE_NAME = 'calendar-reminder-cache-v3';
const ASSETS = [
  '/WebApp/index.html',
  '/WebApp/css/styles.css',
  '/WebApp/css/bootstrap.local.css',
  '/WebApp/js/config.js',
  '/WebApp/js/db.js',
  '/WebApp/js/models.js',
  '/WebApp/js/ui.js',
  '/WebApp/js/main.js',
  '/WebApp/js/singleInstance.js',
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => cache.addAll(ASSETS)).catch(() => null)
  );
});

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

self.addEventListener('fetch', (event) => {
  const req = event.request;
  if (req.method !== 'GET') return;
  event.respondWith(
    caches.match(req).then((cached) => {
      const fetchPromise = fetch(req).then((resp) => {
        const copy = resp.clone();
        caches.open(CACHE_NAME).then((cache) => cache.put(req, copy)).catch(() => {});
        return resp;
      }).catch(() => cached);
      return cached || fetchPromise;
    })
  );
});