const CACHE_NAME = 'secret-message-studio-v3';
const ASSETS = [
  './',
  './index.html',
  './manifest.json',
  './icon.svg',
  'https://cdn.jsdelivr.net/npm/qrcode@1.5.4/build/qrcode.min.js',
  'https://cdn.jsdelivr.net/npm/jsqr@1.4.0/dist/jsQR.min.js'
];

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

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

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