// Service Worker for FlockRadar Offline Driving & Live Updates
const CACHE_NAME = 'flockradar-v9';
const ASSETS_TO_CACHE = [
  './',
  './index.html',
  './css/styles.css?v=9',
  './js/app.js?v=9',
  './js/auth.js?v=9',
  './js/radar.js?v=9',
  './data/portals.js?v=9',
  './manifest.json'
];

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

self.addEventListener('activate', event => {
  event.waitUntil(
    caches.keys().then(keys => Promise.all(
      keys.filter(key => key !== CACHE_NAME).map(key => caches.delete(key))
    )).then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', event => {
  // Always network-first for HTML, JS and CSS to ensure instant updates
  const url = new URL(event.request.url);
  if (url.origin === self.location.origin) {
    event.respondWith(
      fetch(event.request, { cache: 'no-cache' })
        .then(response => {
          if (response && response.status === 200) {
            const clone = response.clone();
            caches.open(CACHE_NAME).then(cache => cache.put(event.request, clone));
          }
          return response;
        })
        .catch(() => caches.match(event.request))
    );
    return;
  }

  // Fallback for CDN resources (Leaflet tiles etc)
  event.respondWith(
    caches.match(event.request).then(cached => {
      return cached || fetch(event.request);
    })
  );
});