// Offline app-shell cache. API calls are never cached. The shell (HTML/JS/CSS)
// is NETWORK-FIRST so code updates land immediately for online clients (a stale
// cache-first app.js is why "?job=" showed no model on an old install); heavy,
// stable assets (three.js vendor, demo.glb, icons) stay cache-first.
const CACHE = 'genrecon-v4';   // bump on shell change so clients refresh
const SHELL = [
  './', './index.html', './styles.css', './app.js', './viewer.js', './manifest.webmanifest',
  './demo.glb', './icons/icon-192.png', './icons/icon-512.png',
  './vendor/three.module.js',
  './vendor/jsm/loaders/GLTFLoader.js', './vendor/jsm/utils/BufferGeometryUtils.js',
  './vendor/jsm/math/Octree.js', './vendor/jsm/math/Capsule.js',
];

self.addEventListener('install', (e) => {
  e.waitUntil(caches.open(CACHE).then((c) => c.addAll(SHELL)).then(() => self.skipWaiting()));
});

self.addEventListener('activate', (e) => {
  e.waitUntil(
    caches.keys()
      .then((ks) => Promise.all(ks.filter((k) => k !== CACHE).map((k) => caches.delete(k))))
      .then(() => self.clients.claim()),
  );
});

self.addEventListener('fetch', (e) => {
  const req = e.request;
  const url = new URL(req.url);
  if (url.pathname.startsWith('/api/')) return;            // dynamic — straight to network, never cached
  const isVendor = url.pathname.includes('/vendor/') || url.pathname.endsWith('.glb') || url.pathname.includes('/icons/');
  const isShell = !isVendor && (req.mode === 'navigate' || /\.(?:js|css|webmanifest)$/.test(url.pathname));
  if (isShell) {
    // Network-first: always try the latest code, cache it, fall back to cache offline.
    e.respondWith(
      fetch(req)
        .then((r) => { const copy = r.clone(); caches.open(CACHE).then((c) => c.put(req, copy)); return r; })
        .catch(() => caches.match(req).then((r) => r || caches.match('./index.html'))),
    );
  } else {
    // Cache-first for heavy, stable assets (three.js, demo.glb, icons).
    e.respondWith(caches.match(req).then((r) => r || fetch(req)));
  }
});