var CACHE_VERSION = 'v2.7.1';
var CACHE_NAME = CACHE_VERSION + ':sw-cache::';
var REQUESTS_LIMIT = 40;

function onInstall(event) {
  event.waitUntil(
    caches.open(CACHE_NAME).then(function prefill(cache) {
      return cache.addAll([
        '<%= asset_path "base.js" %>',
        '<%= asset_path "minimal.css" %>',
        '/offline.html',
        '<%= asset_path "devword.png" %>',
        '<%= asset_path "wires.png" %>',
        '<%= asset_path "comments-bubble.png" %>',
        '<%= asset_path "reactions-stack.png" %>',
        '<%= asset_path "emoji/emoji-one-heart.png" %>',
        '<%= asset_path "emoji/emoji-one-unicorn.png" %>',
        '<%= asset_path "emoji/emoji-one-bookmark.png" %>',
        '<%= asset_path "emoji/apple-fire.png" %>',
      ]).then(function () {
        console.log("WORKER: Install completed");
      });
    })
  );
}

function onActivate(event) {
  console.log('[Serviceworker]', "Activating!", event);
  event.waitUntil(
    caches.keys().then(function(cacheNames) {
      return Promise.all(
        cacheNames.filter(function(cacheName) {
          // Return true if you want to remove this cache,
          return cacheName.indexOf(CACHE_NAME) !== 0;
        }).map(function(cacheName) {
          return caches.delete(cacheName);
        })
      );
    })
  );
}

function onFetch(event) {
  if ( requestBlackListed(event.request) ) { return; }
  event.respondWith(
    caches.match(event.request).then(function (cached) {
      if (cached && shouldReturnStraightFromCache(event.request.url)) {
        return cached;
      }
      return fetch(event.request)
        .then(fetchedFromNetwork)
        .catch(function fallback(err) {
           console.log(err)
           return cached || caches.match('/offline.html');
         })
      }
    )
  );


  function requestBlackListed(request){
    var url = new URL(request.url);
    var test = (event.request.method !== 'GET' ||
                event.request.url.match(/\/notifications(\?|\/)/) ||
                url.host.indexOf("facebook") > -1 ||
                url.host.indexOf("google") > -1 )
    return test
  }

  function shouldReturnStraightFromCache(url) {
    return (url === "<%= asset_path "base.js" %>" ||
                url === "<%= asset_path "minimal.css" %>" ||
                url.indexOf(".self-") > -1 ||
                (url.indexOf("search?") > -1 && url.indexOf("&i=i") > -1) ||
                url.indexOf("freetls.fastly.net") > -1)
  }

  function fetchedFromNetwork(response) {
    var cacheCopy = response.clone();
    caches
      .open(CACHE_NAME + 'pages')
      .then(function add(cache) {
        if ( shouldReturnStraightFromCache(event.request.url) ) {
          cache.put(event.request, cacheCopy);
        }
        garbageCollect(cache);
      })
    return response;
  }

  function garbageCollect(cache) {
    cache.keys().then(function count(keys) {
      if (keys.length > REQUESTS_LIMIT) {
        cache.delete(keys[0]);
        cache.delete(keys[1]);
        cache.delete(keys[2]);
        cache.delete(keys[3]);
        cache.delete(keys[4]);
        cache.delete(keys[5]);
        cache.delete(keys[6]);
        cache.delete(keys[7]);
        cache.delete(keys[8]);
        cache.delete(keys[9]);
        cache.delete(keys[10]);
      }
    })
  }

  function unableToResolve () {
    console.log('WORKER: fetch request failed in both cache and network.');
    return caches.match('/offline.html')
  }
};

function onPush(event) {
  var title = 'DEV Connect 👋 ';
  var body = event.data.text();
  var icon = '<%= image_path "devlogo-pwa-128.png" %>';
  var tag = 'default-tag' + body;
  event.waitUntil(
    self.registration.showNotification(title, {
      body: body,
      icon: icon,
      tag: tag,
      data: {
        url: 'https://dev.to/connect'
      }
    })
  );
};

function onNotificationClick(event) {
  if (Notification.prototype.hasOwnProperty('data')) {
    var url = event.notification.data.url;
    event.waitUntil(clients.openWindow(url));
  }
}


self.addEventListener('install', onInstall);
self.addEventListener('activate', onActivate);
self.addEventListener('fetch', onFetch);
self.addEventListener('push', onPush);
self.addEventListener('notificationclick', onNotificationClick)