const HtmlWebpackPlugin = require('html-webpack-plugin');
const TerserJSPlugin = require('terser-webpack-plugin');
const MiniCSSExtractPlugin = require('mini-css-extract-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');
const path = require('path');
const webpack = require('webpack');
const babelConfig = require('../../babel.config');

const mockModulePath = path.resolve(__dirname, '../mocks/emptyModule.js');

module.exports = (config) => {
  let webpackConfig = {
    entry: {
      main: [path.resolve(__dirname, '../admin/index.js')],
    },
    output: {
      path: path.resolve(process.cwd(), 'build'),
      publicPath: `${config.routes.admin}/`,
      filename: '[name].[chunkhash].js',
      chunkFilename: '[name].[chunkhash].js',
    },
    mode: 'production',
    devtool: 'source-map',
    stats: 'errors-only',
    optimization: {
      minimizer: [new TerserJSPlugin({}), new OptimizeCSSAssetsPlugin({})],
      splitChunks: {
        cacheGroups: {
          styles: {
            name: 'styles',
            test: /\.(sa|sc|c)ss$/,
            chunks: 'all',
            enforce: true,
          },
        },
      },
    },
    resolveLoader: { modules: ['node_modules', path.join(__dirname, '../../node_modules')] },
    module: {
      rules: [
        {
          test: /\.js$/,
          exclude: /node_modules[\\/](?!(@payloadcms[\\/]payload)[\\/]).*/,
          use: {
            loader: 'babel-loader',
            options: babelConfig,
          },
        },
        {
          oneOf: [
            {
              test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
              loader: require.resolve('url-loader'),
              options: {
                limit: 10000,
                name: 'static/media/[name].[hash:8].[ext]',
              },
            },
            {
              test: /\.(sa|sc|c)ss$/,
              sideEffects: true,
              use: [
                MiniCSSExtractPlugin.loader,
                'css-loader',
                {
                  loader: 'postcss-loader',
                  options: {
                    postcssOptions: {
                      plugins: [
                        [
                          'postcss-preset-env',
                          {
                            // Options
                          },
                        ],
                      ],
                    },
                  },
                },
                'sass-loader',
              ],
            },
            {
              exclude: [/\.(js|jsx|mjs)$/, /\.html$/, /\.json$/],
              loader: require.resolve('file-loader'),
              options: {
                name: 'static/media/[name].[hash:8].[ext]',
              },
            },
          ],
        },
      ],
    },
    resolve: {
      modules: ['node_modules', path.resolve(__dirname, '../../node_modules')],
      alias: {
        'payload/unsanitizedConfig': config.paths.config,
        '@payloadcms/payload$': mockModulePath,
      },
    },
    plugins: [
      new HtmlWebpackPlugin({
        template: config.admin && config.admin.indexHTML
          ? path.join(config.paths.configDir, config.admin.indexHTML)
          : path.resolve(__dirname, '../admin/index.html'),
        filename: './index.html',
        minify: true,
      }),
      new webpack.DefinePlugin(Object.entries(config.publicENV).reduce((values, [key, val]) => ({
        ...values,
        [`process.env.${key}`]: `'${val}'`,
      }), {})),
      new MiniCSSExtractPlugin({
        filename: '[name].css',
        ignoreOrder: true,
      }),
    ],
  };

  if (Array.isArray(config.serverModules)) {
    config.serverModules.forEach((mod) => {
      webpackConfig.resolve.alias[mod] = mockModulePath;
    });
  }

  if (process.env.PAYLOAD_ANALYZE_BUNDLE) {
    webpackConfig.plugins.push(new BundleAnalyzerPlugin());
  }

  if (config.paths.scss) {
    webpackConfig.resolve.alias['payload-scss-overrides'] = path.join(config.paths.configDir, config.paths.scss);
  } else {
    webpackConfig.resolve.alias['payload-scss-overrides'] = path.resolve(__dirname, '../admin/scss/overrides.scss');
  }

  if (config.webpack && typeof config.webpack === 'function') {
    webpackConfig = config.webpack(webpackConfig, 'production');
  }

  return webpackConfig;
};