/**
 * TRXTD service worker – makes the game installable as an app (PWA) and
 * keeps it playable offline.
 *
 * Strategy: network-first with runtime caching. The deployed build uses
 * hashed asset names, so index.html must always come from the network to
 * pick up new deploys; the cache is only a fallback when offline.
 * API calls and WebSocket upgrades are never intercepted.
 */
const CACHE = 'trxtd-v1'

self.addEventListener('install', () => {
  self.skipWaiting()
})

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

self.addEventListener('fetch', (event) => {
  const req = event.request
  if (req.method !== 'GET') return

  const url = new URL(req.url)
  if (url.origin !== self.location.origin) return // CDN/external resources
  if (url.pathname.startsWith('/api/')) return // auth & game API: network only
  if (url.pathname.startsWith('/ws')) return

  event.respondWith(
    fetch(req)
      .then((res) => {
        if (res && res.status === 200 && res.type === 'basic') {
          const copy = res.clone()
          caches.open(CACHE).then((c) => c.put(req, copy)).catch(() => {})
        }
        return res
      })
      .catch(() =>
        caches.match(req).then((hit) => hit || caches.match('/')),
      ),
  )
})