"use strict";
const path = require("path");
const utils = require("./utils");
const webpack = require("webpack");
const config = require("../config");
const merge = require("webpack-merge");
const baseWebpackConfig = require("./webpack.base.conf");
const CopyWebpackPlugin = require("copy-webpack-plugin");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const ScriptExtHtmlWebpackPlugin = require("script-ext-html-webpack-plugin");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const OptimizeCSSAssetsPlugin = require("optimize-css-assets-webpack-plugin");
const UglifyJsPlugin = require("uglifyjs-webpack-plugin");

function resolve(dir) {
    return path.join(__dirname, "..", dir);
}

const env = require("../config/" + process.env.env_config + ".env");
// const env = require("../config/prod.env");

// For NamedChunksPlugin
const seen = new Set();
const nameLength = 4;

const webpackConfig = merge(baseWebpackConfig, {
    mode: "production",
    module: {
        rules: utils.styleLoaders({
            sourceMap: config.build.productionSourceMap,
            extract: true,
            usePostCSS: true
        })
    },
    devtool: config.build.productionSourceMap ? config.build.devtool : false,
    output: {
        path: config.build.assetsRoot,
        filename: utils.assetsPath("js/[name].[chunkhash:8].js"),
        chunkFilename: utils.assetsPath("js/[name].[chunkhash:8].js")
    },
    plugins: [
        // http://vuejs.github.io/vue-loader/en/workflow/production.html
        new webpack.DefinePlugin({
            "process.env": env
        }),
        // extract css into its own file
        new MiniCssExtractPlugin({
            filename: utils.assetsPath("css/[name].[contenthash:8].css"),
            chunkFilename: utils.assetsPath("css/[name].[contenthash:8].css")
        }),
        // generate dist index.html with correct asset hash for caching.
        // you can customize output by editing /index.html
        // see https://github.com/ampedandwired/html-webpack-plugin
        new HtmlWebpackPlugin({
            filename: config.build.index,
            template: "index.html",
            inject: true,
            favicon: resolve("favicon.ico"),
            title: "ui-jz-v4",
            templateParameters: {
                BASE_URL: config.build.assetsPublicPath + config.build.assetsSubDirectory
            },
            minify: {
                removeComments: true,
                collapseWhitespace: true,
                removeAttributeQuotes: true
                // more options:
                // https://github.com/kangax/html-minifier#options-quick-reference
            }
            // default sort mode uses toposort which cannot handle cyclic deps
            // in certain cases, and in webpack 4, chunk order in HTML doesn't
            // matter anyway
        }),
        new ScriptExtHtmlWebpackPlugin({
            //`runtime` must same as runtimeChunk name. default is `runtime`
            inline: /runtime\..*\.js$/
        }),
        // keep chunk.id stable when chunk has no name
        new webpack.NamedChunksPlugin(chunk => {
            if (chunk.name) {
                return chunk.name;
            }
            const modules = Array.from(chunk.modulesIterable);
            if (modules.length > 1) {
                const hash = require("hash-sum");
                const joinedHash = hash(modules.map(m => m.id).join("_"));
                let len = nameLength;
                while (seen.has(joinedHash.substr(0, len))) len++;
                seen.add(joinedHash.substr(0, len));
                return `chunk-${joinedHash.substr(0, len)}`;
            } else {
                return modules[0].id;
            }
        }),
        // keep module.id stable when vender modules does not change
        new webpack.HashedModuleIdsPlugin(),
        // copy custom static assets
        new CopyWebpackPlugin([
            {
                from: path.resolve(__dirname, "../static"),
                to: config.build.assetsSubDirectory,
                ignore: [".*"]
            }
        ])
    ],
    optimization: {
        splitChunks: {
            chunks: "all",
            cacheGroups: {
                libs: {
                    name: "chunk-libs",
                    test: /[\\/]node_modules[\\/]/,
                    priority: 10,
                    chunks: "initial" // 只打包初始时依赖的第三方
                },
                elementUI: {
                    name: "chunk-elementUI", // 单独将 elementUI 拆包
                    priority: 20, // 权重要大于 libs 和 app 不然会被打包进 libs 或者 app
                    test: /[\\/]node_modules[\\/]element-ui[\\/]/
                },
                commons: {
                    name: "chunk-commons",
                    test: resolve("src/components"), // 可自定义拓展你的规则
                    minChunks: 3, // 最小公用次数
                    priority: 5,
                    reuseExistingChunk: true
                }
            }
        },
        runtimeChunk: "single",
        minimizer: [
            new UglifyJsPlugin({
                uglifyOptions: {
                    mangle: {
                        safari10: true
                    }
                },
                sourceMap: config.build.productionSourceMap,
                cache: true,
                parallel: true
            }),
            // Compress extracted CSS. We are using this plugin so that possible
            // duplicated CSS from different components can be deduped.
            new OptimizeCSSAssetsPlugin()
        ]
    }
});

if (config.build.productionGzip) {
    const CompressionWebpackPlugin = require("compression-webpack-plugin");

    webpackConfig.plugins.push(
        new CompressionWebpackPlugin({
            algorithm: "gzip",
            test: new RegExp("\\.(" + config.build.productionGzipExtensions.join("|") + ")$"),
            threshold: 10240,
            minRatio: 0.8
        })
    );
}

if (config.build.generateAnalyzerReport || config.build.bundleAnalyzerReport) {
    const BundleAnalyzerPlugin = require("webpack-bundle-analyzer").BundleAnalyzerPlugin;

    if (config.build.bundleAnalyzerReport) {
        webpackConfig.plugins.push(
            new BundleAnalyzerPlugin({
                analyzerPort: 8080,
                generateStatsFile: false
            })
        );
    }

    if (config.build.generateAnalyzerReport) {
        webpackConfig.plugins.push(
            new BundleAnalyzerPlugin({
                analyzerMode: "static",
                reportFilename: "bundle-report.html",
                openAnalyzer: false
            })
        );
    }
}

module.exports = webpackConfig;