/* VistAi — Service Worker v1.0 */

const CACHE = 'vistai-v1';
const SHELL = ['/', '/index.html', '/manifest.json', '/icon-192.png', '/icon-512.png'];

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(keys => Promise.all(keys.filter(k => k !== CACHE).map(k => caches.delete(k))))
      .then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', e => {
  // API — always network
  if (e.request.url.includes('api.php')) {
    e.respondWith(
      fetch(e.request).catch(() =>
        new Response(JSON.stringify({ success: false, message: '// OFFLINE — network unavailable' }),
          { headers: { 'Content-Type': 'application/json' } })
      )
    );
    return;
  }
  // Shell — cache first
  e.respondWith(
    caches.match(e.request).then(cached => {
      if (cached) return cached;
      return fetch(e.request).then(res => {
        if (e.request.method === 'GET' && res.status === 200) {
          caches.open(CACHE).then(c => c.put(e.request, res.clone()));
        }
        return res;
      }).catch(() => caches.match('/index.html'));
    })
  );
});