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

module.exports = (env, argv) => {
  const isDevelopment = argv.mode === 'development'
  
  return {
    entry: './src/main.js',
    output: {
      path: path.resolve(__dirname, 'dist'),
      filename: isDevelopment ? 'bundle.js' : 'bundle.[contenthash:8].js',
      clean: true
    },
    // 开发模式使用高质量的 source map，方便调试
    devtool: isDevelopment ? 'eval-source-map' : 'source-map',
    module: {
      rules: [
        {
          test: /\.vue$/,
          loader: 'vue-loader'
        },
        {
          test: /\.js$/,
          loader: 'babel-loader',
          exclude: /node_modules/
        },
        {
          test: /\.css$/,
          use: [
            'vue-style-loader',
            {
              loader: 'css-loader',
              options: {
                sourceMap: isDevelopment
              }
            }
          ]
        },
        {
          test: /\.less$/,
          use: [
            'vue-style-loader',
            {
              loader: 'css-loader',
              options: {
                sourceMap: isDevelopment
              }
            },
            {
              loader: 'less-loader',
              options: {
                sourceMap: isDevelopment
              }
            }
          ]
        },
        {
          test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
          loader: 'url-loader',
          options: {
            limit: 10000,
            name: 'images/[name].[hash:7].[ext]',
            esModule: false
          }
        },
        {
          test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
          loader: 'url-loader',
          options: {
            limit: 10000,
            name: 'fonts/[name].[hash:7].[ext]',
            esModule: false
          }
        }
      ]
    },
    plugins: [
      new VueLoaderPlugin(),
      new HtmlWebpackPlugin({
        template: './public/index.html',
        filename: 'index.html'
      })
    ],
    resolve: {
      extensions: ['.js', '.vue', '.json'],
      alias: {
        // 框架源码的别名（必须在前面，优先级高）
        '@': path.resolve(__dirname, '../src'),
        '@component': path.resolve(__dirname, '../src/components'),
        '@utils': path.resolve(__dirname, '../src/utils'),
        '@api': path.resolve(__dirname, '../src/api'),
        '@config': path.resolve(__dirname, '../src/config'),
        '@assets': path.resolve(__dirname, '../src/assets'),
        // demo 项目的别名
        '~': path.resolve(__dirname, 'src'),
        'vue$': 'vue/dist/vue.esm.js'
      }
    },
    devServer: {
      port: 8080,
      hot: true,
      open: true,
      historyApiFallback: true,
      // 启用覆盖层显示编译错误
      client: {
        overlay: {
          errors: true,
          warnings: false
        }
      }
    }
  }
}