const path = require('path');
const glob = require('glob');
const TerserPlugin = require('terser-webpack-plugin');
// -------------------------------------------------------------------------------
// Config

const conf = (() => {
  const _conf = require('./build-config');
  return require('deepmerge').all([{}, _conf.base || {}, _conf[process.env.NODE_ENV] || {}]);
})();

conf.distPath = path.resolve(__dirname, conf.distPath);

// -------------------------------------------------------------------------------
// NPM packages to transpile

const TRANSPILE_PACKAGES = ['bootstrap', 'popper.js', 'shepherd.js'];

const packageRegex = package => `(?:\\\\|\\/)${package}(?:\\\\|\\/).+?\\.js$`;

// -------------------------------------------------------------------------------
// Build config

const collectEntries = () => {
  const fileList = glob.sync(`!(${conf.exclude.join('|')})/**/!(_)*.@(js|es6)`) || [];
  return fileList.reduce((entries, file) => {
    const filePath = file.replace(/\\/g, '/');
    return { ...entries, [filePath.replace(/\.(?:js|es6)$/, '')]: `./${filePath}` };
  }, {});
};

const babelLoader = () => ({
  loader: 'babel-loader',
  options: {
    presets: [['@babel/preset-env', { targets: 'last 2 versions, ie >= 10' }]],
    plugins: [
      '@babel/plugin-transform-destructuring',
      '@babel/plugin-transform-object-rest-spread',
      '@babel/plugin-transform-template-literals'
    ],
    babelrc: false
  }
});

const webpackConfig = {
  mode: process.env.NODE_ENV === 'production' ? 'production' : 'development',
  performance: {
    hints: false,
    maxEntrypointSize: 512000,
    maxAssetSize: 512000
  },
  entry: collectEntries(),

  output: {
    path: conf.distPath,
    filename: '[name].js',
    libraryTarget: 'umd'
  },
  module: {
    rules: [
      {
        // Transpile sources
        test: /\.es6$|\.js$/,
        exclude: [path.resolve(__dirname, 'node_modules')],
        use: [babelLoader()]
      },
      {
        // Transpile required packages
        test: new RegExp(`(?:${TRANSPILE_PACKAGES.map(packageRegex).join(')|(?:')})`),
        include: [path.resolve(__dirname, 'node_modules')],
        use: [babelLoader()]
      },
      {
        test: /\.css$/,
        use: [{ loader: 'style-loader' }, { loader: 'css-loader' }]
      },
      {
        test: /\.scss$/,
        use: [{ loader: 'style-loader' }, { loader: 'css-loader' }, { loader: 'sass-loader' }]
      },
      {
        test: /\.html$/,
        use: [
          {
            loader: 'html-loader',
            options: { minimize: true }
          }
        ]
      }
    ]
  },
  optimization: {
    minimize: true,
    minimizer: [
      new TerserPlugin({
        extractComments: false,
        terserOptions: {
          format: {
            comments: false
          },
          compress: {
            drop_console: true
          }
        }
      })
    ]
  },
  plugins: [],

  externals: {
    jquery: 'jQuery',
    moment: 'moment',
    jsdom: 'jsdom',
    velocity: 'Velocity',
    hammer: 'Hammer',
    pace: '"pace-progress"',
    'cross-fetch': 'fetch',
    // chartist: 'Chartist',
    'popper.js': 'Popper',
    // blueimp-gallery plugin
    './blueimp-helper': 'jQuery',
    './blueimp-gallery': 'blueimpGallery',
    './blueimp-gallery-video': 'blueimpGallery'
  }
};

// -------------------------------------------------------------------------------
// Sourcemaps
if (conf.sourcemaps) {
  webpackConfig.devtool = conf.devtool;
}

// -------------------------------------------------------------------------------
// Minify

// Minifies sources by default in production mode
if (process.env.NODE_ENV !== 'production' && conf.minify) {
  webpackConfig.plugins.push(
    new TerserPlugin({
      extractComments: false,
      terserOptions: {
        format: {
          comments: false
        },
        compress: {
          drop_console: true
        }
      },
      parallel: true
    })
  );
}

module.exports = webpackConfig;
