const CACHE = 'ns-v69';
const PRECACHE = ['/', 'index.html', 'manifest.json', 'icon.svg'];
const SKIP_PATHS = ['/rest/stream', '/rest/download', '/config.js'];
// Auth token params stripped from cache keys so artwork survives across sessions/token refreshes.
// The actual fetch still uses the full URL (with token); only the stored key is normalized.
const STRIP_PARAMS = ['t', 's', 'u', 'v', 'c', 'f'];

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

self.addEventListener('activate', e => {
  e.waitUntil(
    caches.keys()
      .then(keys => Promise.all(keys.filter(k => k !== CACHE).map(k => caches.delete(k))))
      .then(() => self.clients.claim())
      .then(() => self.clients.matchAll({ type: 'window', includeUncontrolled: true }))
      .then(clients => clients.forEach(c => c.postMessage({ type: 'SW_UPDATED', version: CACHE })))
  );
});

self.addEventListener('message', e => {
  if (e.data?.type === 'GET_VERSION') {
    e.source.postMessage({ type: 'VERSION', version: CACHE });
  }
});

// Build a stable cache key by stripping Navidrome auth params
function _cacheKey(url) {
  try {
    const u = new URL(url);
    STRIP_PARAMS.forEach(p => u.searchParams.delete(p));
    return u.toString();
  } catch {
    return url;
  }
}

self.addEventListener('fetch', e => {
  if (!e.request.url.startsWith(self.location.origin)) return;
  if (SKIP_PATHS.some(p => e.request.url.includes(p))) return;

  const isCoverArt = e.request.url.includes('/rest/getCoverArt');

  if (isCoverArt) {
    // Cache-first for artwork — serves instantly from SW cache even when Doze blocks network.
    // Key is token-stripped so it survives session restarts with new auth tokens.
    const keyUrl = _cacheKey(e.request.url);
    const keyReq = new Request(keyUrl);
    e.respondWith(
      caches.open(CACHE).then(cache =>
        cache.match(keyReq).then(cached => {
          if (cached) return cached;
          return fetch(e.request).then(res => {
            if (res.status === 200) cache.put(keyReq, res.clone());
            return res;
          }).catch(() => Response.error());
        })
      )
    );
    return;
  }

  // All other requests: network-first, fall back to cache
  e.respondWith(
    fetch(e.request)
      .then(res => {
        if (res.status === 200 && e.request.method === 'GET') {
          const clone = res.clone();
          caches.open(CACHE).then(c => c.put(e.request, clone));
        }
        return res;
      })
      .catch(() => caches.match(e.request).then(r => r || Response.error()))
  );
});