sw.js

const CACHE_NAME = 'scryfall-researcher-static-v2';
const STATIC_URLS = ['./', './index.html', './manifest.json'];

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

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

self.addEventListener('fetch', event => {
  if (event.request.method !== 'GET') return;
  const url = new URL(event.request.url);
  if (url.origin !== self.location.origin || url.pathname.includes('/api.scryfall.com/')) return;

  if (event.request.mode === 'navigate') {
    event.respondWith(fetch(event.request).then(response => {
      const copy = response.clone();
      caches.open(CACHE_NAME).then(cache => cache.put('./index.html', copy));
      return response;
    }).catch(() => caches.match('./index.html')));
    return;
  }

  event.respondWith(caches.match(event.request).then(cached => cached || fetch(event.request).then(response => {
    if (response.ok) {
      const copy = response.clone();
      caches.open(CACHE_NAME).then(cache => cache.put(event.request, copy));
    }
    return response;
  })));
});