const CACHE_NAME = 'hwlab-shell-v1'

// App shell assets to cache on install
const SHELL_ASSETS = [
  '/',
  '/index.html',
]

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

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

self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url)

  // API requests: network only — never cache
  if (url.pathname.startsWith('/api/')) {
    return
  }

  // Navigation requests: serve from cache, fall back to network (app shell)
  if (event.request.mode === 'navigate') {
    event.respondWith(
      caches.match('/').then((cached) => cached ?? fetch(event.request))
    )
    return
  }

  // Static assets: cache-first
  event.respondWith(
    caches.match(event.request).then(
      (cached) => cached ?? fetch(event.request).then((response) => {
        if (response.ok && event.request.method === 'GET') {
          const clone = response.clone()
          caches.open(CACHE_NAME).then((cache) => cache.put(event.request, clone))
        }
        return response
      })
    )
  )
})