const CACHE_NAME = 'llm-in-text-v1';
const APP_SHELL_ASSETS = [
  '/',
  '/index.html',
  '/manifest.webmanifest',
  '/icons/icon-180.png',
  '/icons/icon-192.png',
  '/icons/icon-512.png'
];

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

async function staleWhileRevalidate(request) {
  const cache = await caches.open(CACHE_NAME);
  const cached = await cache.match(request);
  const networkPromise = fetch(request)
    .then((response) => {
      if (response.ok) {
        cache.put(request, response.clone());
      }
      return response;
    })
    .catch(() => cached);

  return cached || networkPromise;
}

self.addEventListener('fetch', (event) => {
  const { request } = event;

  if (request.method !== 'GET') return;

  const url = new URL(request.url);
  if (url.origin !== self.location.origin) return;

  if (url.pathname.startsWith('/v1/')) return;

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

  const cacheableDestinations = ['script', 'style', 'font', 'image', 'worker'];
  if (cacheableDestinations.includes(request.destination)) {
    event.respondWith(staleWhileRevalidate(request));
  }
});