const fs = require('fs');
const path = require('path');
const webpack = require('webpack');
const TerserPlugin = require('terser-webpack-plugin');
const RollbarSourceMapPlugin = require('rollbar-sourcemap-webpack-plugin');
const childProcess = require('child_process');
const remarkSlug = require('remark-slug');
const remarkSectionizeHeadings = require('./webpack/remark_sectionize_headings');
const mdxTableOfContents = require('./webpack/mdx_table_of_contents');

const GIT_SHA = childProcess
    .execSync('git rev-parse HEAD')
    .toString()
    .trim();

const config = {
    entry: ['./ts/index.tsx'],
    output: {
        path: path.join(__dirname, '/public'),
        filename: 'bundle.js',
        chunkFilename: 'bundle-[name].js',
        publicPath: '/',
    },
    externals: {
        zeroExInstant: 'zeroExInstant',
    },
    resolve: {
        modules: [path.join(__dirname, '/ts'), 'node_modules'],
        extensions: ['.ts', '.tsx', '.js', '.jsx', '.json', '.md', '.mdx'],
        alias: {
            ts: path.join(__dirname, '/ts'),
            less: path.join(__dirname, '/less'),
            sass: path.join(__dirname, '/sass'),
            md: path.join(__dirname, '/md'),
            mdx: path.join(__dirname, '/mdx'),
        },
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                loader: 'source-map-loader',
                exclude: [
                    // instead of /\/node_modules\//
                    path.join(process.cwd(), 'node_modules'),
                    path.join(process.cwd(), '../..', 'node_modules'),
                ],
            },
            {
                test: /\.tsx?$/,
                loader: 'awesome-typescript-loader',
            },
            {
                test: /\.mdx$/,
                include: path.join(__dirname, '/mdx'),
                use: [
                    'cache-loader',
                    {
                        loader: 'babel-loader?cacheDirectory',
                        options: {
                            plugins: ['@babel/plugin-syntax-object-rest-spread'],
                            presets: ['@babel/preset-env', '@babel/preset-react'],
                        },
                    },
                    {
                        loader: '@mdx-js/loader',
                        options: {
                            remarkPlugins: [remarkSlug, remarkSectionizeHeadings],
                            compilers: [mdxTableOfContents],
                        },
                    },
                ],
            },

            {
                test: /\.md$/,
                use: 'raw-loader',
            },
            {
                test: /\.less$/,
                use: ['style-loader', 'css-loader', 'less-loader'],
                exclude: /node_modules/,
            },
            {
                test: /\.scss$/,
                use: ['style-loader', 'css-loader', 'sass-loader'],
            },
            {
                test: /\.css$/,
                loaders: ['style-loader', 'css-loader'],
            },

            {
                test: /\.svg$/,
                use: [
                    {
                        loader: 'react-svg-loader',
                        options: {
                            svgo: {
                                plugins: [{ removeViewBox: false }],
                            },
                        },
                    },
                ],
            },
        ],
    },
    optimization: {
        minimizer: [
            new TerserPlugin({
                parallel: true,
                sourceMap: true,
                terserOptions: {
                    mangle: {
                        reserved: ['BigNumber'],
                    },
                },
            }),
        ],
    },
    devServer: {
        host: '0.0.0.0',
        port: 3572,
        historyApiFallback: {
            // Fixes issue where having dots in URL path that aren't part of fileNames causes webpack-dev-server
            // to fail. Doc versions have dots in them, therefore we special case these urls to also load index.html.
            // Source: https://github.com/cvut/fittable/issues/171
            rewrites: [
                {
                    from: /^\/docs\/.*$/,
                    to: function() {
                        return 'index.html';
                    },
                },
            ],
        },
        disableHostCheck: true,
        // Fixes assertion error
        // Source: https://github.com/webpack/webpack-dev-server/issues/1491
        https: {
            spdy: {
                protocols: ['http/1.1'],
            },
        },
    },
};

module.exports = (_env, argv) => {
    const plugins = [];
    if (argv.mode === 'development') {
        config.mode = 'development';
        config.devtool = 'eval-source-map';
        // SSL certs
        if (fs.existsSync('./server.cert') && fs.existsSync('./server.key')) {
            config.devServer.https = {
                ...config.devServer.https,
                key: fs.readFileSync('./server.key'),
                cert: fs.readFileSync('./server.cert'),
            };
        }
    } else {
        config.mode = 'production';
        config.devtool = 'source-map';

        plugins.push(
            // Since we do not use moment's locale feature, we exclude them from the bundle.
            // This reduces the bundle size by 0.4MB.
            new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
            new webpack.DefinePlugin({
                'process.env': {
                    GIT_SHA: JSON.stringify(GIT_SHA),
                },
            }),
        );
        if (process.env.DEPLOY_ROLLBAR_SOURCEMAPS === 'true') {
            plugins.push(
                new RollbarSourceMapPlugin({
                    accessToken: '32c39bfa4bb6440faedc1612a9c13d28',
                    version: GIT_SHA,
                    publicPath: 'https://0x.org/',
                }),
            );
        }
    }
    console.log('i ｢atl｣: Mode: ', config.mode);

    config.plugins = plugins;
    console.log('i ｢atl｣: Plugin Count: ', config.plugins.length);

    return config;
};