const path = require('path');
const fs = require('fs');
const DefinePlugin = require('webpack/lib/DefinePlugin');
const CommonsChunkPlugin = require('webpack/lib/optimize/CommonsChunkPlugin');
const { AutoWebPlugin } = require('web-webpack-plugin');

const autoPlugin = new AutoWebPlugin('./src/pages/', {
  template: (pageName) => {
    let templatePath = path.resolve('./src/pages/', pageName, 'template.html');
    if (fs.existsSync(templatePath)) {
      return templatePath;
    }
    return './src/assets/template.html';
  },
  commonsChunk: {
    name: 'common',
    // 超过4个以上的页面都用到的公共模块就抽取到common里去
    minChunks: 4,
  },
});

module.exports = {
  entry: autoPlugin.entry({
    vendor: './src/assets/vendor',
  }),
  output: {
    publicPath: '',
    filename: '[name].js',
  },
  resolve: {
    // 加快搜索速度
    modules: [path.resolve(__dirname, 'node_modules')],
    // es tree-shaking
    mainFields: ['jsnext:main', 'browser', 'main'],
    // 加快编译速度
    alias: {
      moment: 'moment/min/moment.min.js',
    },
    // 支持 npm link
    symlinks: true,
  },
  module: {
    // 这些库都是不依赖其它库的库 不需要解析他们可以加快编译速度
    noParse: /node_modules\/(moment|chart\.js)/,
    rules: [
      {
        test: /\.js$/,
        // cacheDirectory 缓存babel编译结果加快重新编译速度
        loader: 'babel-loader?cacheDirectory',
        // 只命中src目录里的js文件，加快webpack搜索速度
        include: path.resolve(__dirname, 'src')
      },
      {
        test: /\.js$/,
        // 加载 imui 里的 // @require '.css'
        loaders: ['comment-require-loader'],
        include: [path.resolve(__dirname, 'node_modules/imui')]
      },
      {
        test: /\.scss$/,
        loaders: ['style-loader', 'css-loader', 'sass-loader'],
        include: path.resolve(__dirname, 'src')
      },
      {
        test: /\.css$/,
        loaders: ['style-loader', 'css-loader'],
      },
      {
        test: /\.(gif|png|jpe?g|eot|woff|ttf|svg|pdf)$/,
        loader: 'file-loader',
      },
    ]
  },
  plugins: [
    new DefinePlugin({
      'process.env': {
        // 'NODE_ENV': JSON.stringify('development')
        NODE_ENV: JSON.stringify(process.env.NODE_ENV)
      }
    }),
    autoPlugin,
    // 所有页面都会用到的基础运行环境
    new CommonsChunkPlugin({
      name: 'vendor',
      chunks: ['vendor', 'common']
    }),
  ],
  devtool: 'source-map',
};