/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
// tslint:disable
// TODO: cleanup this file, it's copied as is from Angular CLI.

// Remove .js files from entry points consisting entirely of .css|scss|sass|less|styl.
// To be used together with ExtractTextPlugin.

export class SuppressExtractedTextChunksWebpackPlugin {
  constructor() {}

  apply(compiler: any): void {
    compiler.hooks.compilation.tap(
      'SuppressExtractedTextChunks',
      (compilation: any) => {
        // find which chunks have css only entry points
        const cssOnlyChunks: string[] = [];
        const entryPoints = compilation.options.entry;
        // determine which entry points are composed entirely of css files
        for (let entryPoint of Object.keys(entryPoints)) {
          let entryFiles: string[] | string = entryPoints[entryPoint];
          // when type of entryFiles is not array, make it as an array
          entryFiles = entryFiles instanceof Array ? entryFiles : [entryFiles];
          if (
            entryFiles.every(
              (el: string) => el.match(/\.(css|scss|sass|less|styl)$/) !== null
            )
          ) {
            cssOnlyChunks.push(entryPoint);
          }
        }
        // Remove the js file for supressed chunks
        compilation.hooks.afterSeal.tap('SuppressExtractedTextChunks', () => {
          compilation.chunks
            .filter((chunk: any) => cssOnlyChunks.indexOf(chunk.name) !== -1)
            .forEach((chunk: any) => {
              let newFiles: string[] = [];
              chunk.files.forEach((file: string) => {
                if (file.match(/\.js(\.map)?$/)) {
                  // remove js files
                  delete compilation.assets[file];
                } else {
                  newFiles.push(file);
                }
              });
              chunk.files = newFiles;
            });
        });
        // Remove scripts tags with a css file as source, because HtmlWebpackPlugin will use
        // a css file as a script for chunks without js files.
        // TODO: Enable this once HtmlWebpackPlugin supports Webpack 4
        // compilation.plugin('html-webpack-plugin-alter-asset-tags',
        //   (htmlPluginData: any, callback: any) => {
        //     const filterFn = (tag: any) =>
        //       !(tag.tagName === 'script' && tag.attributes.src.match(/\.css$/));
        //     htmlPluginData.head = htmlPluginData.head.filter(filterFn);
        //     htmlPluginData.body = htmlPluginData.body.filter(filterFn);
        //     callback(null, htmlPluginData);
        //   });
      }
    );
  }
}
