const path = require("path")
const VueLoaderPlugin = require('vue-loader/lib/plugin')
const HTMLPlugin = require('html-webpack-plugin')
const isDEV = process.env.ENV === "development"
const webpack = require("webpack")
const MiniCssExtractPlugin = require("mini-css-extract-plugin")
const config = {
    target: "web",
    entry: path.join(__dirname, "src/index.js"),
    output: {
        filename:"bundle[hash:8].js",
        path: path.join(__dirname, "dist")
    },

    //单独打包框架文件,让浏览器缓存时间更长
    optimization:{
        splitChunks:{
            chunks: 'initial',
            cacheGroups: {
                // react: {
                //     test: /[\\/]node_modules[\\/](react|react-dom)/,
                //     priority: -1
                // },
                vue: {
                    test: /[\\/]node_modules[\\/](vue|vuex)/,
                    priority: -2
                }
            }
        }
    },
    // resolve: {
    //     extensions: ['.js', '.vue', '.json'],
    // },
        //webpack原生只支持js文件类型，只支持ES5语法，我们使用以.vue文件名结尾的文件时，需要为其指定loader
    module: {
        rules: [
            {
                test: /\.vue$/,
                loader: "vue-loader"
            },
            {
                test: /\.jsx$/,
                loader: "babel-loader"
            },
    //         {
    //             test: /\.css$/,
    //             use: ["style-loader", "stylus-loader"]
    //         },
    //         {
    //             test: /\.styl/,
    //             use: [
    //                 "vue-style-loader",
    //                 "css-loader",
    //                 {
    //                     loader: "postcss-loader",
    //                     // 直接使用stylus-loader生成好的sourceMap，提高编译速度
    //                     options: {
    //                         sourceMap: true,
    //                     }
    //                 },
    //                 "stylus-loader"
    //             ],
    //         },
            {
                test: /\.(png|jpg|jpeg|gif|bmp|svg)$/,
                use: [
                    {
                        loader: "url-loader",
                        // 用base64编码小图片减少http请求
                        options: {
                            limit: 1024,
                            name: "[name].[ext]"
                        }
                    }
                ],
            },
        ]
    },
    plugins: [
        new webpack.DefinePlugin({
            "process.env": {
                ENV: isDEV ? "'development'" : "'production'",
            }
        }),
        // new webpack.NoEmitOnErrorsPlugin(),
        new VueLoaderPlugin(),
        new HTMLPlugin()
    ]
};
if (isDEV) {
    config.output.filename="bundle[hash:8].js"
   const loaderPlugin = {
        //css预处理器，使用模块化的方式写css代码
        //stylus-loader专门用来处理stylus文件，处理完成后变成css文件，交给css-loader.webpack的loader就是这样一级一级向上传递，每一层loader只处理自己关心的部分
        test: /\.styl/,
        use: [
            'vue-style-loader',
            'css-loader',
            {
                loader: 'postcss-loader',
                options: { sourceMap: true }
            },
            'stylus-loader'
        ]
    };

    config.module.rules.push(loaderPlugin);
    config.plugins.push(
        new webpack.HotModuleReplacementPlugin(),
    )

    config.devtool = "#cheap-module-eval-source-map"

    config.devServer = {
        port: 8000,
        host: "0.0.0.0",
        // 显示错误到页面
        overlay: {
            errors: true,
        },
        //自动打开浏览器
        // open: true,
        // historyFallback:{
        //
        // }
        // 热加载
        hot: true,
    }
}else {

    // config.entry= {
    //     app:path.join(__dirname, "src/index.js"),
    //     vendor:['vue']
    // }
    config.output.filename="[name].[chunkHash:8].js"
    const loaderPlugin ={
        test: /\.styl/,
        use: [
            {
                loader: MiniCssExtractPlugin.loader,
                options: {
                    // you can specify a publicPath here
                    // by default it uses publicPath in webpackOptions.output
                    publicPath: './',
                    hmr: process.env.NODE_ENV === 'development',
                },
            },
            'css-loader',
            {
                loader: 'postcss-loader',
                options: { sourceMap: true }
            },
            'stylus-loader'
        ]
    };
    config.module.rules.push(loaderPlugin);
    config.plugins.push(
        new MiniCssExtractPlugin({
            // Options similar to the same options in webpackOptions.output
            // all options are optional
            filename: 'styles.[contentHash].[name].css',
            chunkFilename: '[id].css',
            ignoreOrder: false, // Enable to remove warnings about conflicting order
        })
    )
}

module.exports = config