/**
 * Copyright 2015 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

(function() {
  var nativeAddAll = Cache.prototype.addAll;
  var userAgent = navigator.userAgent.match(/(Firefox|Chrome)\/(\d+\.)/);

  // Has nice behavior of `var` which everyone hates
  if (userAgent) {
    var agent = userAgent[1];
    var version = parseInt(userAgent[2]);
  }

  if (
    nativeAddAll && (!userAgent ||
      (agent === 'Firefox' && version >= 46) ||
      (agent === 'Chrome'  && version >= 50)
    )
  ) {
    return;
  }

  Cache.prototype.addAll = function addAll(requests) {
    var cache = this;

    // Since DOMExceptions are not constructable:
    function NetworkError(message) {
      this.name = 'NetworkError';
      this.code = 19;
      this.message = message;
    }

    NetworkError.prototype = Object.create(Error.prototype);

    return Promise.resolve().then(function() {
      if (arguments.length < 1) throw new TypeError();

      // Simulate sequence<(Request or USVString)> binding:
      var sequence = [];

      requests = requests.map(function(request) {
        if (request instanceof Request) {
          return request;
        }
        else {
          return String(request); // may throw TypeError
        }
      });

      return Promise.all(
        requests.map(function(request) {
          if (typeof request === 'string') {
            request = new Request(request);
          }

          var scheme = new URL(request.url).protocol;

          if (scheme !== 'http:' && scheme !== 'https:') {
            throw new NetworkError("Invalid scheme");
          }

          return fetch(request.clone());
        })
      );
    }).then(function(responses) {
      // If some of the responses has not OK-eish status,
      // then whole operation should reject
      if (responses.some(function(response) {
        return !response.ok;
      })) {
        throw new NetworkError('Incorrect response status');
      }

      // TODO: check that requests don't overwrite one another
      // (don't think this is possible to polyfill due to opaque responses)
      return Promise.all(
        responses.map(function(response, i) {
          return cache.put(requests[i], response);
        })
      );
    }).then(function() {
      return undefined;
    });
  };

  Cache.prototype.add = function add(request) {
    return this.addAll([request]);
  };
}());


var dataCacheName = 'PracticoPWA-Data-v1';
var cacheName = 'PracticoPWA-final-1';
var filesToCache = [
  '/',
  '../inc/version_actual.txt',
  '../img/logo.png'
];


self.addEventListener('install', function(event) {
  console.log('Practico Framework: Service worker INSTALLING...');
  event.waitUntil(
    caches.open(cacheName).then(function(cache) {
      console.log('Practico Framework: Service worker CACHING APP SHELL');
      return cache.addAll(filesToCache);
    })
  );
});

self.addEventListener('fetch', function(event) {
console.log("Practico Framework: Service worker "+event.request.url);
event.respondWith(
caches.match(event.request).then(function(response) {
return response || fetch(event.request);
})
);
});

self.addEventListener('activate', function(event) {
  console.log('Practico Framework: Service worker ACTIVATING...');
  event.waitUntil(
    caches.keys().then(function(keyList) {
      return Promise.all(keyList.map(function(key) {
        if (key !== cacheName && key !== dataCacheName) {
          console.log('Practico Framework: Service worker REMOVING OLD CACHE', key);
          return caches.delete(key);
        }
      }));
    })
  );
  /*
   * Fixes a corner case in which the app wasn't returning the latest data.
   * You can reproduce the corner case by commenting out the line below and
   * then doing the following steps: 1) load app for first time so that the
   * initial New York City data is shown 2) press the refresh button on the
   * app 3) go offline 4) reload the app. You expect to see the newer NYC
   * data, but you actually see the initial data. This happens because the
   * service worker is not yet activated. The code below essentially lets
   * you activate the service worker faster.
   */
  return self.clients.claim();
});