'use strict';
const path = require('path');
const utils = require('./utils');
const webpack = require('webpack');
const config = require('../config');
const {merge} = require('webpack-merge');
const baseWebpackConfig = require('./webpack.base.conf');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CssMinimizerPlugin = require("css-minimizer-webpack-plugin");

const env = require('../config/prod.env');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

const webpackConfig = merge(baseWebpackConfig, {
  devtool: config.build.productionSourceMap ? config.build.devtool : false,
  mode: 'production',
  output: {
    path: config.build.assetsRoot,
    filename: utils.assetsPath('js/[name].[chunkhash].js'),
    chunkFilename: utils.assetsPath('js/[id].[chunkhash].js'),
  },
  optimization: {
    minimizer:  [
      new CssMinimizerPlugin()
    ]
  },
  plugins: [
    // http://vuejs.github.io/vue-loader/en/workflow/production.html
    new webpack.DefinePlugin({
      'process.env': env,
      // bundler feature flags https://github.com/vuejs/vue-next/tree/master/packages/vue#bundler-build-feature-flags
      __VUE_OPTIONS_API__: true, // default, but explicit
      __VUE_PROD_DEVTOOLS__: false, // default, but explicit
    }),
    // extract css into its own file
    new MiniCssExtractPlugin({
      filename: utils.assetsPath('css/[name].[contenthash].css'),
    }),
    // generate dist index.html with correct asset hash for caching.
    // you can customize output by editing /index.html
    // see https://github.com/ampedandwired/html-webpack-plugin
    new HtmlWebpackPlugin({
      filename: config.build.index,
      template: 'index.html',
      ...require('../config/prod.env'),
      minify: { // defaults from https://github.com/jantimon/html-webpack-plugin#minification
        collapseWhitespace: true,
        keepClosingSlash: true,
        removeComments: true,
        removeRedundantAttributes: true,
        removeScriptTypeAttributes: true,
        removeStyleLinkTypeAttributes: true,
        useShortDoctype: true,
      },
      // necessary to consistently work with multiple chunks via CommonsChunkPlugin
      chunksSortMode: 'auto',
    }),
    // keep module.id stable when vendor modules does not change
    new webpack.ids.HashedModuleIdsPlugin(),
    // split vendor js into its own file
    // todo: https://gist.github.com/sokra/1522d586b8e5c0f5072d7565c2bee693
    // todo: do we need this? probably default is fine
    // new webpack.optimize.CommonsChunkPlugin({
    //   name: 'vendor',
    //   minChunks (module) {
    //     // any required modules inside node_modules are extracted to vendor
    //     return (
    //       module.resource &&
    //       /\.js$/.test(module.resource) &&
    //       module.resource.indexOf(
    //         path.join(__dirname, '../node_modules')
    //       ) === 0
    //     )
    //   }
    // }),
    // extract webpack runtime and module manifest to its own file in order to
    // prevent vendor hash from being updated whenever app bundle is updated
    // new webpack.optimize.CommonsChunkPlugin({
    //   name: 'manifest',
    //   minChunks: Infinity
    // }),
    // This instance extracts shared chunks from code splitted chunks and bundles them
    // in a separate chunk, similar to the vendor chunk
    // see: https://webpack.js.org/plugins/commons-chunk-plugin/#extra-async-commons-chunk
    // new webpack.optimize.CommonsChunkPlugin({
    //   name: 'app',
    //   async: 'vendor-async',
    //   children: true,
    //   minChunks: 3
    // }),

    // copy custom static assets
    new CopyWebpackPlugin({
      patterns: [
        {
          from: path.resolve(__dirname, '../static'),
          to: config.build.assetsSubDirectory,
          globOptions: {
            ignore: ['.*'],
          },
        },
      ],
    }),
  ],
});

if (config.build.productionGzip) {
  const CompressionWebpackPlugin = require('compression-webpack-plugin');

  webpackConfig.plugins.push(
    new CompressionWebpackPlugin({
      asset: '[path].gz[query]',
      algorithm: 'gzip',
      test: new RegExp(
        '\\.(' +
        config.build.productionGzipExtensions.join('|') +
        ')$',
      ),
      threshold: 10240,
      minRatio: 0.8,
    }),
  );
}

if (config.build.bundleAnalyzerReport) {
  const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;
  webpackConfig.plugins.push(new BundleAnalyzerPlugin());
}

module.exports = webpackConfig;