const CACHE = "who-need-help-static-v1"
const SHELL = ["/assets/css/app.css", "/assets/js/app.js", "/images/logo.svg"]

self.addEventListener("install", event => {
  event.waitUntil(caches.open(CACHE).then(cache => cache.addAll(SHELL)))
})

self.addEventListener("activate", event => {
  event.waitUntil(
    caches.keys().then(keys =>
      Promise.all(keys.filter(key => key !== CACHE).map(key => caches.delete(key)))
    )
  )
})

self.addEventListener("fetch", event => {
  const url = new URL(event.request.url)
  const isStatic =
    url.origin === self.location.origin &&
    (url.pathname.startsWith("/assets/") || url.pathname.startsWith("/images/"))

  if (event.request.method === "GET" && isStatic) {
    event.respondWith(
      caches.match(event.request).then(cached =>
        cached || fetch(event.request).then(response => {
          const copy = response.clone()
          caches.open(CACHE).then(cache => cache.put(event.request, copy))
          return response
        })
      )
    )
  }
})