import { join } from "path"

import {
  HotModuleReplacementPlugin,
  DllReferencePlugin,
} from "webpack"
import WebpackNotifierPlugin from "webpack-notifier"

import HtmlWebpackPlugin from "html-webpack-plugin"


const defaultEnv = {
  production: process.env.NODE_ENV === "production",
  dev: !process.env.NODE_ENV || process.env.NODE_ENV === "",
  test: process.env.NODE_ENV === "test",
}

export default (env) => {
  env = {
    ...defaultEnv,
    ...env,
  }

  return {
    module: {
      loaders: [
        // ...
      ],
    },

    plugins: [
      new HtmlWebpackPlugin({
        template: join(__dirname, "entry", "index.html"),
        inject: false,
        ...env.dll && {
          externals: [ "/dependencies.dll.js" ],
        },
      }),

      ...env.dev ? [
        new WebpackNotifierPlugin(),
        new HotModuleReplacementPlugin(),
      ] : [],

      ...env.dll ? [
        new DllReferencePlugin({
          context: __dirname,
          // generated by webpack.dll.config.babel.js
          manifest: require("./dist/dependencies.dll.manifest.json"),
          // name: "./dist/dependencies.dll.js",
        }),
      ] : [],
    ],

    entry: {
      // ...
    },

    output: {
      // publicPath has to be defined so HtmlWebpackPlugin serve correct js
      // in script tags
      // (because historyApiFallback will root things like /a/b to the
      // index.html, and script tag need a absolute url for the script)
      publicPath: "/",

      path: "dist",
      filename: "[name].[hash].js",
    },

    devServer: {
      // when you serve static files during development, this is necessary
      // eg: dependencies.dll.js
      contentBase: "dist",
    },
  }
}