// Minimal offline app-shell cache — deliberately narrow: only the small set
// of same-origin static files that make up the page itself. Never touches
// the chat API (cross-origin, and never GET) or the CDN libraries (marked,
// DOMPurify, pdf.js, highlight.js, the Google Font) — those should always
// go through the browser's normal cache/network so a library update or a
// worker deploy is picked up immediately, not stuck behind a stale SW cache.
const CACHE_NAME = 'nox-shell-v2';
const APP_SHELL = [
  './',
  './index.html',
  './manifest.json',
  './devseis-logo.png',
  './icon-192.png',
  './icon-192-alert.png',
  './icon-512.png',
];

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

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();
});

self.addEventListener('fetch', (event) => {
  const req = event.request;
  if (req.method !== 'GET') return;
  const url = new URL(req.url);
  if (url.origin !== self.location.origin) return;
  if (!APP_SHELL.some((p) => url.pathname.endsWith(p.replace('./', '')) || (p === './' && url.pathname === '/'))) return;

  // Network-first so a redeploy is visible on next load when online; falls
  // back to the cached shell only when the network actually fails (offline).
  event.respondWith(
    fetch(req)
      .then((res) => {
        const copy = res.clone();
        caches.open(CACHE_NAME).then((cache) => cache.put(req, copy)).catch(() => {});
        return res;
      })
      .catch(() => caches.match(req))
  );
});