const webpack = require('webpack')
const path = require('path')
const merge = require('webpack-merge')
const commonConfig = require('./helpers/webpack.common.config')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
const UglifyJsPlugin = require('uglifyjs-webpack-plugin')
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const HtmlWebpackHarddiskPlugin = require('html-webpack-harddisk-plugin')
const ScriptExtHtmlWebpackPlugin = require('script-ext-html-webpack-plugin')
const Dotenv = require('dotenv-webpack')
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer')
  .BundleAnalyzerPlugin

module.exports = merge(commonConfig, {
  mode: 'production',
  devtool: 'inline-sourcemap',
  output: {
    path: path.resolve(__dirname, '../../build'),
    filename: 'script.js'
  },

  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        cache: true,
        parallel: true,
        sourceMap: false
      }),
      new OptimizeCSSAssetsPlugin({})
    ],
    splitChunks: {
      cacheGroups: {
        styles: {
          name: 'styles',
          test: /\.css$/,
          chunks: 'all',
          enforce: true
        }
      }
    }
  },
  plugins: [
    new Dotenv(),
    new MiniCssExtractPlugin({
      filename: '[name].css',
      chunkFilename: '[id].css'
    }),
    new HtmlWebpackPlugin({
      template: 'html/index.html',
      alwaysWriteToDisk: true
    }),
    new ScriptExtHtmlWebpackPlugin({
      defaultAttribute: 'async'
    }),
    new HtmlWebpackHarddiskPlugin(),
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify('production')
    }),
    new BundleAnalyzerPlugin({
      analyzerMode: 'static',
      reportFilename: 'report.html'
    })
  ],
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: [
          /(node_modules|bower_components)/
        ],
        loader: 'babel-loader',
        options: {
          presets: ['@babel/preset-env', '@babel/preset-react']
        }
      },
      {
        test: /\.scss$/,
        use: [
          MiniCssExtractPlugin.loader,
          { loader: 'css-loader', options: { importLoaders: 2 } },
          'postcss-loader',
          { loader: 'sass-loader' }
        ]
      }
    ]
  },
  target: 'web'
})