const CACHE_NAME = 'opus-loop-v1';
const ASSETS_TO_CACHE = [
  '/',
  '/index.html',
  '/manifest.json',
  '/images/logo.svg',
  '/images/icon-192.png',
  '/images/icon-512.png',
];

// Install - precache shell
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => cache.addAll(ASSETS_TO_CACHE))
  );
  self.skipWaiting();
});

// Activate - clean old caches
self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((keys) =>
      Promise.all(keys.filter((k) => k !== CACHE_NAME).map((k) => caches.delete(k)))
    )
  );
  self.clients.claim();
});

// Fetch - network first for pages, cache first for assets
self.addEventListener('fetch', (event) => {
  const { request } = event;
  const url = new URL(request.url);

  // Skip non-GET and cross-origin
  if (request.method !== 'GET' || url.origin !== location.origin) return;

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

  // Videos: cache first with network fallback (range-request aware)
  if (url.pathname.startsWith('/videos/')) {
    event.respondWith(
      caches.match(request).then((cached) => {
        if (cached) return cached;
        return fetch(request).then((response) => {
          if (response.ok) {
            const clone = response.clone();
            caches.open(CACHE_NAME).then((cache) => cache.put(request, clone));
          }
          return response;
        });
      })
    );
    return;
  }

  // Other assets: stale-while-revalidate
  event.respondWith(
    caches.match(request).then((cached) => {
      const fetching = fetch(request).then((response) => {
        if (response.ok) {
          const clone = response.clone();
          caches.open(CACHE_NAME).then((cache) => cache.put(request, clone));
        }
        return response;
      });
      return cached || fetching;
    })
  );
});