/*******************************************************************************
 * © Apployees Inc., 2019
 * All Rights Reserved.
 ******************************************************************************/
import { IBuildWebserverBuilderOptions } from "../common/webserver-types";
import { getAssetsUrl } from "../common/env";
import postcssNormalize from "postcss-normalize";
import {
  cssModuleRegex,
  cssRegex,
  getCSSModuleLocalIdent,
  lessModuleRegex,
  lessRegex,
  sassModuleRegex,
  sassRegex,
} from "../common/common-loaders";
import _ from "lodash";
import MiniCssExtractPlugin from "mini-css-extract-plugin";
import NodeSass from "node-sass";

export function getClientLoaders(options: IBuildWebserverBuilderOptions) {
  const isEnvDevelopment: boolean = options.dev;
  const isEnvProduction = !isEnvDevelopment;

  const shouldUseSourceMap = isEnvDevelopment && options.sourceMapForStyles;

  // Webpack uses `publicPath` to determine where the app is being served from.
  // It requires a trailing slash, or the file assets will get an incorrect path.
  // In development, we always serve from the root. This makes config easier.
  const publicPath = getAssetsUrl(options);
  // Some apps do not use client-side routing with pushState.
  // For these, "homepage" can be set to "." to enable relative asset paths.
  const shouldUseRelativeAssetPaths = publicPath.startsWith(".");

  let styleOrExtractLoader;
  if (isEnvDevelopment) {
    styleOrExtractLoader = _.isString(require.resolve("style-loader"))
      ? require.resolve("style-loader")
      : "style-loader";
  } else {
    styleOrExtractLoader = {
      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: shouldUseRelativeAssetPaths ? { publicPath: "../../" } : {},
    };
  }

  // common function to get style loaders
  const getStyleLoaders = (isForModule: boolean, cssOptions?) => {
    cssOptions = isForModule
      ? {
          ...cssOptions,
          localsConvention: "dashesOnly",
          modules: {
            localIdentName: getCSSModuleLocalIdent(isEnvDevelopment),
          },
        }
      : cssOptions;

    return [
      // For some reason, webpack is unable to load the CSS
      // files that are extracted from this MiniCssExtractPlugin
      // Therefore, for now, we are going to use style-loader regardless of dev or production mode,
      // and comment out MiniCssExtractPlugin

      styleOrExtractLoader,
      {
        loader: _.isString(require.resolve("css-loader")) ? require.resolve("css-loader") : "css-loader",
        options: {
          ...cssOptions,
          sourceMap: shouldUseSourceMap,
        },
      },
      {
        // Options for PostCSS as we reference these options twice
        // Adds vendor prefixing based on your specified browser support in
        // package.json
        loader: _.isString(require.resolve("postcss-loader")) ? require.resolve("postcss-loader") : "postcss-loader",
        options: {
          // Necessary for external CSS imports to work
          // https://github.com/facebook/create-react-app/issues/2677
          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: shouldUseSourceMap,
        },
      },
    ].filter(Boolean);
  };

  return [
    // "url" loader works like "file" loader except that it embeds assets
    // smaller than specified limit in bytes as data URLs to avoid requests.
    // A missing `test` is equivalent to a match.
    {
      test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/, /\.woff$/, /\.woff2$/, /\.avi$/, /\.mp4$/, /\.mp3$/],
      loader: _.isString(require.resolve("url-loader")) ? require.resolve("url-loader") : "url-loader",
      options: {
        limit: options.imageInlineSizeLimit,
        name: "static/media/[name].[hash:8].[ext]",
      },
    },
    // "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(false, {
        importLoaders: 1,
        sourceMap: shouldUseSourceMap,
      }),
      // 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(true, {
        importLoaders: 1,
      }),
    },
    // 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(false, {
        importLoaders: 2,
      }).concat({
        loader: _.isString(require.resolve("sass-loader")) ? require.resolve("sass-loader") : "sass-loader",
        options: {
          implementation: NodeSass,
          sourceMap: shouldUseSourceMap,
        },
      }),
      // 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(true, {
        importLoaders: 2,
      }).concat({
        loader: _.isString(require.resolve("sass-loader")) ? require.resolve("sass-loader") : "sass-loader",
        options: {
          implementation: NodeSass,
          sourceMap: shouldUseSourceMap,
        },
      }),
    },
    // Opt-in support for LESS (using .less).
    // By default we support LESS Modules with the
    // extensions .module.LESS
    {
      test: lessRegex,
      exclude: lessModuleRegex,
      use: getStyleLoaders(false, {
        importLoaders: 2,
      }).concat({
        loader: _.isString(require.resolve("less-loader")) ? require.resolve("less-loader") : "less-loader",
        options: {
          sourceMap: shouldUseSourceMap,
          javascriptEnabled: true,
          modifyVars: options.lessStyleVariables_calculated,
        },
      }),
      // 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 less
    // using the extension .module.less
    {
      test: lessModuleRegex,
      use: getStyleLoaders(true, {
        importLoaders: 2,
      }).concat({
        loader: _.isString(require.resolve("less-loader")) ? require.resolve("less-loader") : "less-loader",
        options: {
          sourceMap: shouldUseSourceMap,
          javascriptEnabled: true,
          modifyVars: options.lessStyleVariables_calculated,
        },
      }),
    },
    // "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: _.isString(require.resolve("file-loader")) ? require.resolve("file-loader") : "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]",
      },
    },
  ];
}