import {
  DefinePlugin,
  NamedModulesPlugin,
  HashedModuleIdsPlugin,
  LoaderOptionsPlugin,
  ContextReplacementPlugin,
  HotModuleReplacementPlugin,
  NoEmitOnErrorsPlugin,

  optimize,
} from 'webpack';

import path from 'path';
import { isatty } from 'tty';
import chalk from 'chalk';
import slash from 'slash';
import autoprefixer from 'autoprefixer';
import CaseSensitivePathsPlugin from 'case-sensitive-paths-webpack-plugin';
import ExtractTextPlugin from 'extract-text-webpack-plugin';
import HtmlPlugin from 'html-webpack-plugin';
import ProgressBarPlugin from 'progress-bar-webpack-plugin';

const {
  CommonsChunkPlugin,
  UglifyJsPlugin,
  ModuleConcatenationPlugin,
} = optimize;

const locales = ['en'];

/**
 * Plugin for HtmlPlugin which inlines content for an extracted Webpack manifest
 * into the HTML in a <script> tag before other emitted asssets are injected by
 * HtmlPlugin itself.
 */
function injectManifestPlugin() {
  this.plugin('compilation', (compilation) => {
    compilation.plugin('html-webpack-plugin-before-html-processing', (data, cb) => {
      Object.keys(compilation.assets).forEach((key) => {
        if (!key.startsWith('manifest.')) { return; }
        const { children } = compilation.assets[key];
        if (children && children[0]) {
          // eslint-disable-next-line no-param-reassign
          data.html = data.html.replace(/^(\s*)<\/body>/m, `$1<script>${children[0]._value}</script>\n$1</body>`);
          // Remove the manifest from HtmlPlugin's assets to prevent a <script>
          // tag being created for it.
          const manifestIndex = data.assets.js.indexOf(data.assets.publicPath + key);
          data.assets.js.splice(manifestIndex, 1);
          // eslint-disable-next-line no-param-reassign
          delete data.assets.chunks.manifest;
        }
      });
      cb(null, data);
    });
  });
}

export default (options) => {
  const environment = {
    development: true,
    production: false,
    server: false,
  };

  function processEnvironmentString(env) {
    switch (env.toLowerCase()) {
      case 'development':
        environment.development = true;
        environment.production = false;
        break;
      case 'production':
        environment.development = false;
        environment.production = true;
        break;
      case 'server':
        environment.server = true;
        break;
      default:
        console.warn('Unknown environment:', env);
        break;
    }
  }

  if (options) {
    switch (true) {
      case typeof (options) === 'string': // string
        processEnvironmentString(options);
        break;

      case Array.isArray(options): // array
        options.forEach(processEnvironmentString);
        break;

      default: // object
        Object.keys(options).forEach((k) => {
          environment[k] = options[k] || environment[k];
        });
        break;
    }
  } else if (process.env.NODE_ENV) {
    processEnvironmentString(process.env.NODE_ENV);
  }

  const {
    development,
    production,
    server,
  } = environment;

  const baseOutputFilename = development
    ? 'assets/dev/[name].dev.[ext]'
    // Always use a hash (in production) to prevent files with the same name causing issues
    : 'assets/prod/[chunkhash:2]/[name].[chunkhash:8].[ext]';

  const webpackChunkFilename = baseOutputFilename
    .replace(/\[ext(.*?)\]/g, 'js');
  const webpackOutputFilename = webpackChunkFilename;

  const assetOutputFilename = baseOutputFilename
    .replace(/\[chunkhash(.*?)\]/g, '[hash$1]');

  const cssOutputFileName = baseOutputFilename
    .replace(/\[ext(.*?)\]/g, 'css')
    .replace(/\[chunkhash(.*?)\]/g, '[contenthash$1]');
  const cssOutputRebasePath = `${slash(path.relative(path.dirname(cssOutputFileName), ''))}/`;

  // Default options for url-loader
  const urlLoaderOptions = {
    limit: 1, // Don't inline anything (but empty files) by default
    name: assetOutputFilename,
    publicPath: cssOutputRebasePath,
  };

  function styleLoaders(...preprocessingLoaders) {
    let cssLoaders = [
      {
        loader: 'style-loader',
      },
      {
        loader: 'css-loader',
        options: {
          importLoaders: 1,
          sourceMap: true,
          modules: true,
        },
      },
      {
        loader: 'postcss-loader',
        options: {
          ident: 'postcss',
          plugins: [
            autoprefixer({
              browsers: '> 1%, last 4 versions, Firefox ESR, ios >= 8',
              grid: false,
            }),
          ],
          sourceMap: true,
        },
      },
    ].filter(loader => loader !== false);

    if (preprocessingLoaders && preprocessingLoaders.length > 0) {
      cssLoaders.push(
        {
          loader: 'resolve-url-loader',
          options: {
            fail: true,
            silent: false,
          },
        },
        ...preprocessingLoaders.map(loader => Object.assign({}, loader, {
          options: Object.assign({}, loader.options || {}, {
            sourceMap: true,
          }),
        })),
      );
    }

    if (!server) {
      const fallback = cssLoaders.shift();
      cssLoaders = ExtractTextPlugin.extract({
        fallback,
        use: cssLoaders,
      });
    }

    return cssLoaders;
  }

  return {
    devServer: {
      // inline: true,
      headers: {
        'Access-Control-Allow-Origin': '*',
      },
      historyApiFallback: true,
      hot: true,
      noInfo: true,
      overlay: true,
      publicPath: '',
      quiet: true,
      watchOptions: {
        ignored: /node_modules/,
      },
    },
    module: {
      rules: [
        {
          test: /\.jsx?/,
          loader: 'babel-loader',
          exclude: /node_modules/,
          options: {
          // Look for babel configuration in project directory
            babelrc: true,
            // Cache transformations to the filesystem (in default temp dir)
            cacheDirectory: true,
          },
        },
        ...[
          /\.(gif|png|webp)$/i, // graphics
          /\.svg$/i, // svg
          /\.jpe?g$/i, // jpeg
          /\.(mp4|ogg|webm)$/i, // video
          /\.(eot|otf|ttf|woff|woff2)$/i, // fonts
          /\.(wav|mp3|m4a|aac|oga)$/i, // audio
        ].map(test => ({
          test,
          loader: 'url-loader',
          options: urlLoaderOptions,
        })),
        {
          test: /\.css$/,
          use: styleLoaders(),
        },
        {
          test: /\.s[ac]ss$/,
          use: styleLoaders(
            {
              loader: 'sass-loader',
            },
          ),
        },
      ],
      strictExportPresence: true,
    },
    output: {
      filename: webpackOutputFilename,
      chunkFilename: webpackChunkFilename,
      path: path.join(__dirname, 'dist'),
      publicPath: '',
    },
    plugins: [
    // Show progress as a bar during build
      isatty(1) && new ProgressBarPlugin({
        complete: chalk.white('\u2588'),
        incomplete: chalk.grey('\u2591'),
        format: `:bar ${chalk.cyan.bold(':percent')} Webpack build: ${chalk.grey(':msg')}`,
      }),

      // Enforce case-sensitive import paths
      new CaseSensitivePathsPlugin(),
      // Replace specified expressions with values
      new DefinePlugin({
        'process.env.__DEV__': JSON.stringify(development),
        'process.env.__PROD__': JSON.stringify(production),
        'process.env.__SERVER__': JSON.stringify(server),
        'process.env.NODE_ENV': JSON.stringify(production ? 'production' : 'development'),
      }),

      // Dev server build
      ...[
      // Hot module reloading
        new HotModuleReplacementPlugin(),
        new NoEmitOnErrorsPlugin(),

        // Use paths as names when serving
        new NamedModulesPlugin(),
      ].filter(() => server),

      // If we're not serving, we're creating a static build
      ...[// Extract imported stylesheets out into .css files
        new ExtractTextPlugin({
          allChunks: true,
          filename: cssOutputFileName,
        }),
      ].filter(() => !server),

      // Move modules imported from node_modules/ into a vendor chunk when enabled
      new CommonsChunkPlugin({
        name: 'vendor',
        minChunks(module) {
          return (module.resource && module.resource.includes('node_modules'));
        },
      }),

      // If we're generating an HTML file, we must be building a web app, so
      // configure deterministic hashing for long-term caching.

      // Generate stable module ids instead of having Webpack assign integers.
      // NamedModulesPlugin allows for easier debugging and
      // HashedModuleIdsPlugin does this without adding too much to bundle
      // size.
      development
        ? new NamedModulesPlugin()
        : new HashedModuleIdsPlugin(),

      // The Webpack manifest is normally folded into the last chunk, changing
      // its hash - prevent this by extracting the manifest into its own
      // chunk - also essential for deterministic hashing.
      new CommonsChunkPlugin({ name: 'manifest' }),

      // Inject the Webpack manifest into the generated HTML as a <script>
      injectManifestPlugin,

      // Production builds
      ...[
      // JavaScript minification
        new LoaderOptionsPlugin({ debug: false, minimize: true }),
        new UglifyJsPlugin({
          compress: {
            warnings: false,
          },
          output: {
            comments: false,
          },
          sourceMap: true,
        }),

        // Hoisting
        new ModuleConcatenationPlugin(),
      ].filter(() => production),

      new HtmlPlugin({
        template: 'src/index.html',
        filename: 'index.html',
        hash: false,
        inject: true,
        compile: true,
        favicon: false,
        minify: false,
        cache: true,
        showErrors: true,
        chunks: 'all',
        excludeChunks: [],
        title: 'Webpack App',
        xhtml: false,
        chunksSortMode: 'dependency',
      }),

      // Only include selected locales for moment.js
      new ContextReplacementPlugin(/moment[/\\]locale$/, new RegExp(`^\\.\\/(${locales.join('|')})$`)),
    ].filter(plugin => plugin !== false),
    resolve: {
      extensions: [
        '.js', '.json', '.jsx',
      ],
      alias: {
        // Use preact instead of react
        /* react: 'preact-compat\\dist\\preact-compat',
        'react-dom': 'preact-compat\\dist\\preact-compat',
        'create-react-class': 'preact-compat/lib/create-react-class', */

        'moment-timezone': 'moment-timezone/builds/moment-timezone-with-data-2012-2022.js',
      },
    },
    resolveLoader: {
      modules: ['node_modules', 'nwb'],
    },
    devtool: server ? 'cheap-module-source-map' : 'source-map',
    entry: {
      app: [
        ...[
          'eventsource-polyfill',
          'react-hot-loader/patch',
          'webpack-hot-middleware/client',
        ].filter(() => server),
        './src',
      ],
    },
  };
};