const path = require('path');
const webpack = require('webpack');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
require('@babel/register');

const devMode = (process.env.NODE_ENV !== 'production' && process.argv.indexOf('-p') === -1);

const config = {
  entry: ['@babel/polyfill', `${__dirname}/src/components/index.js`],

  output: {
    path: `${__dirname}/build`,
    publicPath: '/build/',
    filename: 'bundle.js',
  },

  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        cache: true,
        parallel: true,
        sourceMap: true,
        extractComments: true
      }),
      new OptimizeCSSAssetsPlugin({})
    ],
    splitChunks: {
      cacheGroups: {
        styles: {
          name: 'styles',
          test: /\.css$/,
          chunks: 'all',
          enforce: true
        }
      }
    }
  },

  module: {
    rules: [
      {
        test: /\.(js|jsx)$/, 
        exclude: /node_modules/,
        loader: 'babel-loader',
        options: {
          'presets': [
            '@babel/preset-env',
            '@babel/preset-react',
            '@babel/preset-flow',
          ],
          'plugins': [
            '@babel/plugin-transform-runtime',
            ['@babel/plugin-proposal-decorators', {'legacy': true }],
            ['@babel/plugin-proposal-class-properties', { 'loose': true }]
          ]
        }
      },
      {
        test: /\.s?[ac]ss$/,
        use: [
          devMode ? 'style-loader' : MiniCssExtractPlugin.loader,
          'css-loader',
          'sass-loader',
        ],
      }
    ]
  },

  resolve: {
    extensions: ['.js', '.jsx'],
  },

  node: {
    fs: 'empty',
  },

  // First array is dev only, second is production
  plugins: devMode ? [] : [
    new webpack.DefinePlugin({
      'process.env.NODE_ENV': JSON.stringify('production'),
    }),
    new MiniCssExtractPlugin({
      filename: '[name].css',
      chunkFilename: '[id].css',
    })
  ],
};

// Exports
module.exports = config;