sw.js

const CACHE_NAME = 'block-display-generator-v1';
const APP_SHELL = [
  './',
  './index.html',
  './css/styles.css',
  './js/app.js',
  './js/block-display.js',
  './manifest.json',
  './assets/icons/icon.svg',
  './assets/icons/icon-192.png',
  './assets/icons/icon-512.png'
];

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

async function networkFirst(request) {
  try {
    const response = await fetch(request);
    if (response && response.ok) {
      const cache = await caches.open(CACHE_NAME);
      await cache.put(request, response.clone());
    }
    return response;
  } catch (error) {
    const cached = await caches.match(request);
    if (cached) return cached;
    if (request.mode === 'navigate') return caches.match('./index.html');
    throw error;
  }
}

self.addEventListener('fetch', (event) => {
  const request = event.request;
  if (request.method !== 'GET') return;
  const url = new URL(request.url);
  if (url.origin !== self.location.origin) return;
  event.respondWith(networkFirst(request));
});