const CACHE_NAME = 'timetracker-test-v1';
const urlsToCache = ['/', '/index.html'];

self.addEventListener('install', event => {
  console.log('[SW] Install');
  event.waitUntil(
    caches.open(CACHE_NAME).then(cache => {
      console.log('[SW] Caching shell:', urlsToCache);
      return cache.addAll(urlsToCache);
    }).catch(err => console.error('[SW] Install failed:', err))
  );
});

self.addEventListener('activate', event => {
  console.log('[SW] Activate');
  event.waitUntil(
    caches.keys().then(cacheNames =>
      Promise.all(
        cacheNames.map(name => {
          if (name !== CACHE_NAME) {
            console.log('[SW] Deleting old cache:', name);
            return caches.delete(name);
          }
        })
      )
    )
  );
});

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

  event.respondWith(
    caches.match(event.request).then(cached => {
      if (cached) {
        console.log('[SW] Cache hit:', event.request.url);
        return cached;
      }

      return fetch(event.request).then(networkRes => {
        return networkRes;
      }).catch(err => {
        console.error('[SW] Fetch failed:', event.request.url, err);
        return new Response('Offline', { status: 503 });
      });
    })
  );
});