// NOTE: This service worker is for the web/PWA build.
// For development we aggressively unregister SWs in `src/player.js`.
//
// Bump this value whenever caching logic changes to guarantee clients don't
// keep an old UI after updates.
const CACHE_NAME = 'radioplayer-pwa-v4';

const CORE_ASSETS = [
  './',
  'index.html',
  'stations.json',
  'manifest.json',
  'assets/radioplayer-logo-192.png',
  'assets/radioplayer-logo-512.png',
];

const CORE_PATHS = new Set(CORE_ASSETS.map((p) => new URL(p, self.registration.scope).pathname));

self.addEventListener('install', (event) => {
  // Activate updated SW as soon as it's installed.
  self.skipWaiting();
  event.waitUntil(
    caches.open(CACHE_NAME).then(async (cache) => {
      const reqs = CORE_ASSETS.map((p) => new Request(p, { cache: 'reload' }));
      await cache.addAll(reqs);

      // Vite fingerprints JS/CSS assets in production. Parse the built HTML so
      // the installed PWA can launch offline after its first install.
      try {
        const indexResp = await fetch(new Request('./', { cache: 'reload' }));
        const indexText = await indexResp.clone().text();
        await cache.put('./', indexResp);

        const assetUrls = [...indexText.matchAll(/(?:src|href)="([^"]+)"/g)]
          .map((match) => match[1])
          .filter((assetPath) => assetPath.startsWith('./assets/') || assetPath.startsWith('assets/'))
          .map((assetPath) => new URL(assetPath, self.registration.scope).href);

        await Promise.all(assetUrls.map((assetUrl) => {
          return cache.add(new Request(assetUrl, { cache: 'reload' })).catch(() => {});
        }));
      } catch (e) {
        // If HTML parsing fails, runtime caching below still catches assets.
      }
    })
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    Promise.all([
      self.clients.claim(),
      caches.keys().then((keys) => Promise.all(
        keys.map((k) => { if (k !== CACHE_NAME) return caches.delete(k); return null; })
      )),
    ])
  );
});

self.addEventListener('fetch', (event) => {
  // Only handle GET requests
  if (event.request.method !== 'GET') return;

  const url = new URL(event.request.url);

  // Don't cache cross-origin requests (station logos, APIs, etc.).
  if (url.origin !== self.location.origin) {
    return;
  }

  const isCore = CORE_PATHS.has(url.pathname);
  const isHtmlNavigation = event.request.mode === 'navigate' || (event.request.headers.get('accept') || '').includes('text/html');

  // Network-first for navigations and core assets to prevent "old UI" issues.
  if (isHtmlNavigation || isCore) {
    event.respondWith(
      fetch(event.request)
        .then((networkResp) => {
          const respClone = networkResp.clone();
          caches.open(CACHE_NAME).then((cache) => cache.put(event.request, respClone)).catch(() => {});
          return networkResp;
        })
        .catch(() => caches.match(event.request).then((cached) => cached || caches.match('./') || caches.match('index.html')))
    );
    return;
  }

  event.respondWith(
    caches.match(event.request).then((cached) => {
      if (cached) return cached;
      return fetch(event.request).then((networkResp) => {
        // Optionally cache new resources (best-effort)
        try {
          const respClone = networkResp.clone();
          caches.open(CACHE_NAME).then((cache) => cache.put(event.request, respClone)).catch(()=>{});
        } catch (e) {}
        return networkResp;
      }).catch(() => {
        // If offline and HTML navigation, return cached index.html
        if (event.request.mode === 'navigate') return caches.match('./') || caches.match('index.html');
        return new Response('', { status: 503, statusText: 'Service Unavailable' });
      });
    })
  );
});