/**
 * Copyright 2018 Google LLC
 *
 * 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.
 */

const CODE = `<script>(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)})(window,document,'script','//www.google-analytics.com/analytics.js','ga');ga('create','{{ID}}','auto');ga('send','pageview');</script>`;

export default class GoogleAnalyticsPlugin {
  constructor ({ id }) {
    this.id = id;
  }
  apply (compiler) {
    compiler.hooks.compilation.tap('ga', compilation => {
      compilation.hooks.htmlWebpackPluginAfterHtmlProcessing.tap('ga', ({ html }) => ({
        html: html.replace('</body>', CODE.replace('{{ID}}', this.id) + '</body>')
      }));
    });
  }
}