'use strict';

const CACHE = 'chimera-shell-v1';
const SHELL = ['/offline.html', '/manifest.webmanifest', '/build/icon.png'];

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

self.addEventListener('activate', event => {
  event.waitUntil(caches.keys().then(keys => Promise.all(keys.filter(key => key.startsWith('chimera-shell-') && key !== CACHE).map(key => caches.delete(key)))).then(() => self.clients.claim()));
});

function cacheable(url) {
  return url.origin === self.location.origin && (url.pathname === '/manifest.webmanifest' || url.pathname === '/offline.html' || url.pathname === '/build/icon.png' || url.pathname.startsWith('/styles/') || url.pathname.startsWith('/modules/'));
}

self.addEventListener('fetch', event => {
  if (event.request.method !== 'GET') return;
  const url = new URL(event.request.url);
  if (event.request.mode === 'navigate') {
    event.respondWith(fetch(event.request).catch(() => caches.match('/offline.html')));
    return;
  }
  if (!cacheable(url)) return;
  const isIcon = url.pathname === '/build/icon.png';
  const cacheFallback = isIcon ? '/build/icon.png' : event.request;
  event.respondWith(
    fetch(event.request).then(response => {
      if (response.ok && response.type === 'basic') {
        caches.open(CACHE).then(cache => {
          cache.put(event.request, response.clone());
          if (isIcon) cache.put(cacheFallback, response.clone());
        });
      }
      return response;
    }).catch(() => caches.match(cacheFallback)),
  );
});