/* ════════════════════════════════════════════════════
   AMUSEMENT — Service Worker
   Cache-first strategy for offline PWA support
   ════════════════════════════════════════════════════ */

const CACHE_NAME = 'amusement-v1';
const ASSETS = [
  './',
  './index.html',
  './style.css',
  './app.js',
  './manifest.json',
];

// Install: pre-cache core assets
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => cache.addAll(ASSETS))
  );
  self.skipWaiting();
});

// Activate: clean old caches
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();
});

// Fetch: cache-first, fallback to network
self.addEventListener('fetch', (event) => {
  event.respondWith(
    caches.match(event.request).then((cached) => {
      if (cached) return cached;
      return fetch(event.request).then((response) => {
        if (!response || response.status !== 200 || response.type !== 'basic') {
          return response;
        }
        const clone = response.clone();
        caches.open(CACHE_NAME).then((cache) => cache.put(event.request, clone));
        return response;
      });
    }).catch(() => {
      // If both cache and network fail, return offline fallback
      if (event.request.mode === 'navigate') {
        return caches.match('./index.html');
      }
    })
  );
});