const path = require('path')
const webpack = require('webpack')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const { VueLoaderPlugin } = require('vue-loader')

module.exports = (env, argv) => {
  // 仅当传入 env_file 时加载 .env（build:sit / build:prod），否则 dev 用 development，build 用 prod
  const envFile = env && env.env_file
  if (envFile) {
    require('dotenv').config({ path: path.resolve(__dirname, envFile) })
  }
  const buildEnv = process.env.BUILD_ENV || (argv.mode === 'production' ? 'prod' : 'development')
  return {
  entry: './src/main.js',
  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'js/[name].[contenthash:8].js',
    chunkFilename: 'js/[name].[contenthash:8].chunk.js',
    clean: true
  },
  optimization: {
    splitChunks: {
      chunks: 'all',
      minSize: 20000,
      maxSize: 244000,
      cacheGroups: {
        // Vue 相关库单独打包
        vue: {
          test: /[\\/]node_modules[\\/](vue|vue-router|vuex|vue-loader|vue-template-compiler)[\\/]/,
          name: 'vue',
          priority: 30,
          reuseExistingChunk: true
        },
        // UI 库单独打包
        ui: {
          test: /[\\/]node_modules[\\/](view-design|iview)[\\/]/,
          name: 'ui',
          priority: 25,
          reuseExistingChunk: true
        },
        // 其他第三方库打包
        vendor: {
          test: /[\\/]node_modules[\\/]/,
          name: 'vendors',
          priority: 10,
          reuseExistingChunk: true
        },
        // 公共代码
        common: {
          name: 'common',
          minChunks: 2,
          priority: 5,
          reuseExistingChunk: true
        }
      }
    },
    // 运行时代码单独打包
    runtimeChunk: {
      name: 'runtime'
    },
    // 生产环境启用压缩
    minimize: process.env.NODE_ENV === 'production'
  },
  module: {
    rules: [
      {
        test: /\.vue$/,
        loader: 'vue-loader'
      },
      {
        test: /\.js$/,
        loader: 'babel-loader',
        exclude: /node_modules/
      },
      {
        test: /\.css$/,
        use: ['vue-style-loader', 'css-loader']
      },
      {
        test: /\.less$/,
        use: ['vue-style-loader', 'css-loader', 'less-loader']
      },
      {
        test: /\.(png|jpe?g|gif|svg|woff2?|eot|ttf|otf)$/,
        type: 'asset/resource',
        generator: {
          filename: 'assets/[name].[hash:8][ext]'
        }
      }
    ]
  },
  plugins: [
    new webpack.DefinePlugin({
      __APP_BUILD_ENV__: JSON.stringify(buildEnv),
      'process.env.BUILD_ENV': JSON.stringify(buildEnv)
    }),
    new VueLoaderPlugin(),
    new HtmlWebpackPlugin({
      template: './public/index.html',
      title: '管理后台'
    })
  ],
  resolve: {
    extensions: ['.js', '.vue', '.json'],
    alias: {
      '@': path.resolve(__dirname, 'src'),
      'vue$': 'vue/dist/vue.esm.js'
    }
  },
  devServer: {
    hot: true,
    open: true,
    port: 8080,
    historyApiFallback: true
  }
  }
}