const CACHE_NAME = 'pinail2-cache-v1';
const APP_SHELL = [
  '/',
  '/static/style.css',
  '/static/app.js',
  '/static/img/pi_favicon.png',
  '/static/img/pinail_logo.svg',
  '/static/manifest.webmanifest'
];

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

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

self.addEventListener('fetch', function(event) {
  if (event.request.method !== 'GET') {
    return;
  }

  event.respondWith(
    fetch(event.request)
      .then(function(response) {
        const cloned = response.clone();
        caches.open(CACHE_NAME).then(function(cache) {
          cache.put(event.request, cloned);
        });
        return response;
      })
      .catch(function() {
        return caches.match(event.request).then(function(cached) {
          return cached || caches.match('/');
        });
      })
  );
});