// This code executes in its own worker or thread
self.addEventListener("install", event => {
   console.log("Service worker installed");
});
self.addEventListener("activate", event => {
   console.log("Service worker activated");
});


self.addEventListener("fetch", event => {
   // Stratégie Cache-First
   event.respondWith(
      caches
         .match(event.request) // On vérifie si la requête a déjà été mise en cache
         .then(cached => cached || fetch(event.request)) // sinon on requête le réseau
         .then(
            response =>
               cache(event.request, response) // on met à jour le cache
                  .then(() => response) // et on résout la promesse avec l'objet Response
         )
   );
});

/*
function cache(request, response) {
   if (response.type === "error" || response.type === "opaque") {
      return Promise.resolve(); // do not put in cache network errors
   }

   return caches
      .open(CACHE_NAME)
      .then(cache => cache.put(request, response.clone()));
}
*/

const CACHE_NAME = "V2";

self.addEventListener("activate", event => {
   // delete any unexpected caches
   event.waitUntil(
      caches
         .keys()
         .then(keys => keys.filter(key => key !== CACHE_NAME))
         .then(keys =>
            Promise.all(
               keys.map(key => {
                  console.log(`Deleting cache ${key}`);
                  return caches.delete(key);
               })
            )
         )
   );
});