sw.js

const CACHE_NAME = 'smartwaste-cache-v1';

self.addEventListener('install', event => {
  // Cache root page only on install, to have something in cache from start
  event.waitUntil(
    caches.open(CACHE_NAME).then(cache => cache.add('/'))
  );
  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 => {
  // Only handle GET requests from same origin
  if (event.request.method !== 'GET' || !event.request.url.startsWith(self.location.origin)) {
    return;
  }

  event.respondWith(
    fetch(event.request)
      .then(networkResponse => {
        // Cache the successful response clone dynamically
        if (networkResponse && networkResponse.status === 200) {
          const responseClone = networkResponse.clone();
          caches.open(CACHE_NAME).then(cache => {
            cache.put(event.request, responseClone);
          });
        }
        return networkResponse;
      })
      .catch(() => {
        // On network failure, return from cache if available
        return caches.match(event.request);
      })
  );
});