// 开发环境参数设置
const Setting = require("./src/settings.env");
// 拼接路径
const resolve = dir => require("path").join(__dirname, dir);
// 是否开发环境
const isDev = process.env.NODE_ENV === "development";

module.exports = {
  publicPath: Setting.publicPath,
  lintOnSave: Setting.lintOnSave,
  outputDir: Setting.outputDir,
  assetsDir: Setting.assetsDir,
  runtimeCompiler: true,
  productionSourceMap: false,
  devServer: {
    open: true, // 自动启动浏览器
    port: 5189,
    disableHostCheck: true, // 禁用host检查
    publicPath: Setting.publicPath,
    // 浏览器弹出错误
    overlay: {
      warnings: false,
      errors: true
    }
    // proxy: { }
  },

  configureWebpack: {
    // provide the app's title in webpack's name field, so that
    // it can be accessed in index.html to inject the correct title.
    // name: name,
    resolve: {
      alias: {
        "@": resolve("src")
      }
    },
    // 发布时关闭警告
    performance: {
      hints: false
    }
  },
  // webpack配置
  // see https://github.com/vuejs/vue-cli/blob/dev/docs/webpack.md
  chainWebpack(config) {
    /**
     * 删除懒加载模块的 prefetch preload，降低带宽压力
     * https://cli.vuejs.org/zh/guide/html-and-static-assets.html#prefetch
     * https://cli.vuejs.org/zh/guide/html-and-static-assets.html#preload
     * 而且预渲染时生成的 prefetch 标签是 modern 版本的，低版本浏览器是不需要的
     */
    config.plugins.delete("prefetch").delete("preload");

    config
      // https://webpack.js.org/configuration/devtool/#development
      .when(isDev, config => config.devtool("cheap-source-map"));

    config.when(!isDev, config => {
      config.optimization.splitChunks({
        chunks: "all",
        cacheGroups: {
          libs: {
            name: "chunk-libs",
            test: /[\\/]node_modules[\\/]/,
            priority: 10,
            chunks: "initial" // only package third parties that are initially dependent
          },
          elementUI: {
            name: "chunk-elementUI", // split elementUI into a single package
            priority: 20, // the weight needs to be larger than libs and app or it will be packaged into libs or app
            test: /[\\/]node_modules[\\/]_?element-ui(.*)/ // in order to adapt to cnpm
          },
          commons: {
            name: "chunk-commons",
            test: resolve("src/components"), // can customize your rules
            minChunks: 3, //  minimum common number
            priority: 5,
            reuseExistingChunk: true
          }
        }
      });
      config.optimization.runtimeChunk("single");
    });

    config.plugin("html").tap(args => {
      args[0].title = Setting.defaultTitle;
      return args;
    });
  },
  // css相关配置
  css: {
    // 是否使用css分离插件 ExtractTextPlugin
    extract: true,
    sourceMap: false,
    // css预设器配置项
    loaderOptions: {},
    // 启用 CSS modules for all css / pre-processor files.
    // modules: false,
    requireModuleExtension: true
  },
  // use thread-loader for babel & TS in production build
  // enabled by default if the machine has more than 1 cores
  parallel: require("os").cpus().length > 1
};