// Plants vs Zombies PWA Service Worker (Offline Support)
const CACHE_NAME = 'pvz-web-v2.3';
const ASSETS_TO_CACHE = [
  './',
  './index.html',
  './manifest.json',
  './favicon.ico',
  './icon-192.png',
  './icon-512.png',
  './css/style.css',
  './js/main.js',
  './js/game.js',
  './js/entities/plant.js',
  './js/entities/zombie.js',
  './js/entities/projectile.js',
  './js/systems/grid.js',
  './js/systems/economy.js',
  './js/systems/combat.js',
  './js/systems/campaign.js',
  './js/systems/feedback.js',
  './js/systems/wave.js',
  './js/systems/workshop.js',
  './js/systems/zengarden.js',
  './js/systems/almanac.js',
  './js/systems/achievements.js',
  './js/systems/roguelike.js',
  './js/systems/tree.js',
  './js/systems/boss.js',
  './js/systems/leaderboard.js',
  './js/systems/auth.js',
  './js/utils/assets.js',
  './js/utils/test_api.js'
];

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

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

self.addEventListener('fetch', (event) => {
  // Navigation or static asset request
  if (event.request.method !== 'GET') return;

  event.respondWith(
    caches.match(event.request).then((cachedResponse) => {
      if (cachedResponse) {
        // Fetch in background to update cache
        fetch(event.request).then((networkResponse) => {
          if (networkResponse && networkResponse.status === 200) {
            caches.open(CACHE_NAME).then((cache) => cache.put(event.request, networkResponse));
          }
        }).catch(() => {});
        return cachedResponse;
      }
      return fetch(event.request).then((networkResponse) => {
        if (!networkResponse || networkResponse.status !== 200 || networkResponse.type !== 'basic') {
          return networkResponse;
        }
        const responseToCache = networkResponse.clone();
        caches.open(CACHE_NAME).then((cache) => {
          cache.put(event.request, responseToCache);
        });
        return networkResponse;
      }).catch(() => {
        // Fallback to cached index.html for navigation requests
        if (event.request.mode === 'navigate') {
          return caches.match('./index.html');
        }
      });
    })
  );
});