const path = require('path');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

const fs = require('fs');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const InlineChunkHtmlPlugin = require('react-dev-utils/InlineChunkHtmlPlugin');
const TerserPlugin = require('terser-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const safePostCssParser = require('postcss-safe-parser');
const { WebpackManifestPlugin: ManifestPlugin } = require('webpack-manifest-plugin');
const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
const WorkboxWebpackPlugin = require('workbox-webpack-plugin');
const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');
const getCSSModuleLocalIdent = require('react-dev-utils/getCSSModuleLocalIdent');
const ModuleNotFoundPlugin = require('react-dev-utils/ModuleNotFoundPlugin');
const ForkTsCheckerWebpackPlugin = require('react-dev-utils/ForkTsCheckerWebpackPlugin');
const typescriptFormatter = require('react-dev-utils/typescriptFormatter');

const postcssNormalize = require('postcss-normalize');
const resolvePath = (relative) => path.resolve(fs.realpathSync(process.cwd()), relative);

const shouldInlineRuntimeChunk = process.env.INLINE_RUNTIME_CHUNK !== 'false';

const emitErrorsAsWarnings = process.env.ESLINT_NO_DEV_ERRORS === 'true';
const disableESLintPlugin = process.env.DISABLE_ESLINT_PLUGIN === 'true';

const imageInlineSizeLimit = parseInt(process.env.IMAGE_INLINE_SIZE_LIMIT || '10000');

// Check if TypeScript is setup
const useTypeScript = fs.existsSync(resolvePath('tsconfig.json'));

const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== 'false';
const cssRegex = /\.css$/;
const cssModuleRegex = /\.module\.css$/;
const sassRegex = /\.(scss|sass)$/;
const sassModuleRegex = /\.module\.(scss|sass)$/;
const swSrc = 'not-existing-file.txt';

module.exports = (webpackEnv) => {
    // const isEnvDevelopment = webpackEnv === 'development';
    const isEnvDevelopment = false;
    // const isEnvProduction = webpackEnv === 'production';
    const isEnvProduction = !isEnvDevelopment;

    const getStyleLoaders = (cssOptions, preProcessor) => {
        const loaders = [
            isEnvDevelopment && require.resolve('style-loader'),
            isEnvProduction && {
                loader: MiniCssExtractPlugin.loader,
                // css is located in `static/css`, use '../../' to locate index.html folder
                // in production `paths.publicUrlOrPath` can be a relative path
                options: { publicPath: '../../' },
            },
            {
                loader: require.resolve('css-loader'),
                options: cssOptions,
            },
            {
                // Options for PostCSS as we reference these options twice
                // Adds vendor prefixing based on your specified browser support in
                // package.json
                loader: require.resolve('postcss-loader'),
                options: {
                    // Necessary for external CSS imports to work
                    // https://github.com/facebook/create-react-app/issues/2677
                    postcssOptions: {
                        ident: 'postcss',
                        plugins: () => [
                            require('postcss-flexbugs-fixes'),
                            require('postcss-preset-env')({
                                autoprefixer: {
                                    flexbox: 'no-2009',
                                },
                                stage: 3,
                            }),
                            // Adds PostCSS Normalize as the reset css with default options,
                            // so that it honors browserslist config in package.json
                            // which in turn let's users customize the target behavior as per their needs.
                            postcssNormalize(),
                        ],
                    },
                    sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
                },
            },
        ].filter(Boolean);
        if (preProcessor) {
            loaders.push(
                {
                    loader: require.resolve('resolve-url-loader'),
                    options: {
                        sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
                        root: resolvePath('src/client'),
                    },
                },
                {
                    loader: require.resolve(preProcessor),
                    options: {
                        sourceMap: true,
                    },
                }
            );
        }
        return loaders;
    };

    return {
        mode: 'development',
        entry: './src/client/ts/index.tsx',
        output: {
            path: resolvePath('www'),
            pathinfo: isEnvDevelopment,
            filename: 'index.bundle.js',
            // futureEmitAssets: true,
            // publicPath: '.',
            // // Point sourcemap entries to original disk location (format as URL on Windows)
            // devtoolModuleFilenameTemplate: isEnvProduction
            //     ? (info) => path.relative(paths.appSrc, info.absoluteResourcePath).replace(/\\/g, '/')
            //     : isEnvDevelopment && ((info) => path.resolve(info.absoluteResourcePath).replace(/\\/g, '/')),
            // globalObject: 'this',
        },
        devtool: 'inline-source-map',
        resolve: {
            extensions: ['.tsx', '.ts', '.js', '.jsx'],
        },
        module: {
            strictExportPresence: true,
            rules: [
                {
                    // Disable require.ensure as it's not a standard language feature.
                    parser: {
                        requireEnsure: false,
                    },
                },
                {
                    // "oneOf" will traverse all following loaders until one will
                    // match the requirements. When no loader matches it will fall
                    // back to the "file" loader at the end of the loader list.
                    oneOf: [
                        {
                            test: /\.(ts|tsx)$/,
                            exclude: /node_modules/,
                            use: {
                                loader: 'ts-loader',
                            },
                        },
                        {
                            test: /\.(js|jsx)$/,
                            exclude: /node_modules/,
                            use: {
                                loader: 'babel-loader',
                            },
                        },

                        // "postcss" loader applies autoprefixer to our CSS.
                        // "css" loader resolves paths in CSS and adds assets as dependencies.
                        // "style" loader turns CSS into JS modules that inject <style> tags.
                        // In production, we use MiniCSSExtractPlugin to extract that CSS
                        // to a file, but in development "style" loader enables hot editing
                        // of CSS.
                        // By default we support CSS Modules with the extension .module.css
                        {
                            test: cssRegex,
                            exclude: cssModuleRegex,
                            use: getStyleLoaders({
                                importLoaders: 1,
                                sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
                            }),
                            // Don't consider CSS imports dead code even if the
                            // containing package claims to have no side effects.
                            // Remove this when webpack adds a warning or an error for this.
                            // See https://github.com/webpack/webpack/issues/6571
                            sideEffects: true,
                        },
                        // Adds support for CSS Modules (https://github.com/css-modules/css-modules)
                        // using the extension .module.css
                        {
                            test: cssModuleRegex,
                            use: getStyleLoaders({
                                importLoaders: 1,
                                sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
                                modules: {
                                    getLocalIdent: getCSSModuleLocalIdent,
                                },
                            }),
                        },
                        // Opt-in support for SASS (using .scss or .sass extensions).
                        // By default we support SASS Modules with the
                        // extensions .module.scss or .module.sass
                        {
                            test: sassRegex,
                            exclude: sassModuleRegex,
                            use: getStyleLoaders(
                                {
                                    importLoaders: 3,
                                    sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
                                },
                                'sass-loader'
                            ),
                            // Don't consider CSS imports dead code even if the
                            // containing package claims to have no side effects.
                            // Remove this when webpack adds a warning or an error for this.
                            // See https://github.com/webpack/webpack/issues/6571
                            sideEffects: true,
                        },
                        // Adds support for CSS Modules, but using SASS
                        // using the extension .module.scss or .module.sass
                        {
                            test: sassModuleRegex,
                            use: getStyleLoaders(
                                {
                                    importLoaders: 3,
                                    sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
                                    modules: {
                                        getLocalIdent: getCSSModuleLocalIdent,
                                    },
                                },
                                'sass-loader'
                            ),
                        },

                        // "file" loader makes sure those assets get served by WebpackDevServer.
                        // When you `import` an asset, you get its (virtual) filename.
                        // In production, they would get copied to the `build` folder.
                        // This loader doesn't use a "test" so it will catch all modules
                        // that fall through the other loaders.
                        {
                            loader: require.resolve('file-loader'),
                            // Exclude `js` files to keep "css" loader working as it injects
                            // its runtime that would otherwise be processed through "file" loader.
                            // Also exclude `html` and `json` extensions so they get processed
                            // by webpacks internal loaders.
                            exclude: [/\.(js|mjs|jsx|ts|tsx)$/, /\.html$/, /\.json$/],
                            options: {
                                name: 'static/media/[name].[hash:8].[ext]',
                            },
                        },
                        // ** STOP ** Are you adding a new loader?
                        // Make sure to add the new loader(s) before the "file" loader.
                    ],
                },
            ],
        },
        plugins: [
            // Generates an `index.html` file with the <script> injected.
            new HtmlWebpackPlugin(
                Object.assign(
                    {},
                    {
                        inject: true,
                        template: resolvePath('src/client/index.html'),
                    },
                    isEnvProduction
                        ? {
                              minify: {
                                  removeComments: true,
                                  collapseWhitespace: true,
                                  removeRedundantAttributes: true,
                                  useShortDoctype: true,
                                  removeEmptyAttributes: true,
                                  removeStyleLinkTypeAttributes: true,
                                  keepClosingSlash: true,
                                  minifyJS: true,
                                  minifyCSS: true,
                                  minifyURLs: true,
                              },
                          }
                        : undefined
                )
            ),
            // Inlines the webpack runtime script. This script is too small to warrant
            // a network request.
            // https://github.com/facebook/create-react-app/issues/5358
            isEnvProduction &&
                shouldInlineRuntimeChunk &&
                new InlineChunkHtmlPlugin(HtmlWebpackPlugin, [/runtime-.+[.]js/]),
            //TODO entfernen?
            // Makes some environment variables available in index.html.
            // The public URL is available as %PUBLIC_URL% in index.html, e.g.:
            // <link rel="icon" href="%PUBLIC_URL%/favicon.ico">
            // It will be an empty string unless you specify "homepage"
            // in `package.json`, in which case it will be the pathname of that URL.
            // new InterpolateHtmlPlugin(HtmlWebpackPlugin, env.raw),

            // This gives some necessary context to module not found errors, such as
            // the requesting resource.
            new ModuleNotFoundPlugin(resolvePath('.')),

            //TODO Check
            // Makes some environment variables available to the JS code, for example:
            // if (process.env.NODE_ENV === 'production') { ... }. See `./env.js`.
            // It is absolutely essential that NODE_ENV is set to production
            // during a production build.
            // Otherwise React will be compiled in the very slow development mode.
            // new webpack.DefinePlugin(env.stringified),

            //TODO Check
            // // Watcher doesn't work well if you mistype casing in a path so we use
            // // a plugin that prints an error when you attempt to do this.
            // // See https://github.com/facebook/create-react-app/issues/240
            // isEnvDevelopment && new CaseSensitivePathsPlugin(),

            isEnvProduction &&
                new MiniCssExtractPlugin({
                    // Options similar to the same options in webpackOptions.output
                    // both options are optional
                    //TODO evtl in static ordner?
                    filename: 'css/[name].[contenthash:8].css',
                    chunkFilename: 'css/[name].[contenthash:8].chunk.css',
                }),

            //TODO publicPath anpassen
            // Generate an asset manifest file with the following content:
            // - "files" key: Mapping of all asset filenames to their corresponding
            //   output file so that tools can pick it up without having to parse
            //   `index.html`
            // - "entrypoints" key: Array of files which are included in `index.html`,
            //   can be used to reconstruct the HTML if necessary
            new ManifestPlugin({
                fileName: 'asset-manifest.json',
                publicPath: '.',
                generate: (seed, files, entrypoints) => {
                    const manifestFiles = files.reduce((manifest, file) => {
                        manifest[file.name] = file.path;
                        return manifest;
                    }, seed);
                    const entrypointFiles = entrypoints.main.filter((fileName) => !fileName.endsWith('.map'));

                    return {
                        files: manifestFiles,
                        entrypoints: entrypointFiles,
                    };
                },
            }),

            // Generate a service worker script that will precache, and keep up to date,
            // the HTML & assets that are part of the webpack build.
            isEnvProduction &&
                fs.existsSync(swSrc) &&
                new WorkboxWebpackPlugin.InjectManifest({
                    swSrc,
                    dontCacheBustURLsMatching: /\.[0-9a-f]{8}\./,
                    exclude: [/\.map$/, /asset-manifest\.json$/, /LICENSE/],
                    // Bump up the default maximum size (2mb) that's precached,
                    // to make lazy-loading failure scenarios less likely.
                    // See https://github.com/cra-template/pwa/issues/13#issuecomment-722667270
                    maximumFileSizeToCacheInBytes: 5 * 1024 * 1024,
                }),
        ].filter(Boolean),
    };
};