const path = require("path");
const MonacoWebpackPlugin = require("monaco-editor-webpack-plugin");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const { EnvironmentPlugin } = require("webpack");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const CopyWebpackPlugin = require("copy-webpack-plugin");
const CleanWebpackPlugin = require("clean-webpack-plugin");
const CaseSensitivePathsPlugin = require("case-sensitive-paths-webpack-plugin");
const CreateFileWebpack = require("create-file-webpack");
const childProcess = require("child_process");
const BundleAnalyzerPlugin = require("webpack-bundle-analyzer").BundleAnalyzerPlugin;
const TerserPlugin = require("terser-webpack-plugin");
const isCI = require("is-ci");

const gitSha = childProcess.execSync("git rev-parse HEAD").toString("utf8");

const cssRule = {
  test: /\.css$/,
  use: [MiniCssExtractPlugin.loader, "css-loader"]
};

const lessRule = {
  test: /\.less$/,
  use: [MiniCssExtractPlugin.loader, "css-loader", "less-loader"],
  exclude: [path.resolve(__dirname, "less/Common/Constants.less")]
};

const imagesRule = {
  test: /\.(jpg|jpeg|png|gif|svg|pdf|ico)$/,
  loader: "file-loader",
  options: {
    name: "images/[name].[ext]"
  }
};

const fontRule = {
  test: /\.(woff|woff2|ttf|eot)$/,
  loader: "file-loader",
  options: {
    name: "[name].[ext]"
  }
};

const htmlRule = {
  test: /\.html$/,
  use: [
    {
      loader: "html-loader",
      options: {
        minify: false,
        removeComments: false,
        collapseWhitespace: false,
        root: path.resolve(__dirname, "images")
      }
    }
  ]
};

// We compile our own code with ts-loader
const typescriptRule = {
  test: /\.tsx?$/,
  use: [
    {
      loader: "ts-loader",
      options: {
        transpileOnly: true
      }
    }
  ],
  exclude: /node_modules/
};

// Third party modules are compiled with babel since using ts-loader that much causes webpack to run out of memory
const ModulesRule = {
  test: /\.js$/,
  use: [
    {
      loader: "babel-loader",
      options: {
        cacheDirectory: ".cache/babel",
        presets: [["@babel/preset-env", { targets: { ie: "11" }, useBuiltIns: false }]]
      }
    }
  ],
  include: /node_modules/,
  // Exclude large modules we know don't need transpiling
  exclude: /vega|monaco|plotly/
};

module.exports = function(env = {}, argv = {}) {
  const mode = argv.mode || "development";
  const rules = [fontRule, lessRule, imagesRule, cssRule, htmlRule, typescriptRule];
  const envVars = {
    GIT_SHA: gitSha,
    PORT: process.env.PORT || "1234"
  };

  if (mode === "production") {
    rules.push(ModulesRule);
    envVars.NODE_ENV = "production";
  }

  if (mode === "development") {
    envVars.NODE_ENV = "development";
  }

  const plugins = [
    new CleanWebpackPlugin(["dist"]),
    new CreateFileWebpack({
      path: "./dist",
      fileName: "version.txt",
      content: `${gitSha.trim()} ${new Date().toUTCString()}`
    }),
    new CaseSensitivePathsPlugin(),
    new MiniCssExtractPlugin({
      filename: "[name].[contenthash].css"
    }),
    new HtmlWebpackPlugin({
      filename: "explorer.html",
      template: "src/explorer.html",
      chunks: ["main"]
    }),
    new HtmlWebpackPlugin({
      filename: "terminal.html",
      template: "src/Terminal/index.html",
      chunks: ["terminal"]
    }),
    new HtmlWebpackPlugin({
      filename: "quickstart.html",
      template: "src/quickstart.html",
      chunks: ["quickstart"]
    }),
    new HtmlWebpackPlugin({
      filename: "index.html",
      template: "src/index.html",
      chunks: ["index"]
    }),
    new HtmlWebpackPlugin({
      filename: "hostedExplorer.html",
      template: "src/hostedExplorer.html",
      chunks: ["hostedExplorer"]
    }),
    new HtmlWebpackPlugin({
      filename: "Heatmap.html",
      template: "src/Controls/Heatmap/Heatmap.html",
      chunks: ["heatmap"]
    }),
    new HtmlWebpackPlugin({
      filename: "notebookViewer.html",
      template: "src/NotebookViewer/notebookViewer.html",
      chunks: ["notebookViewer"]
    }),
    new HtmlWebpackPlugin({
      filename: "gallery.html",
      template: "src/GalleryViewer/galleryViewer.html",
      chunks: ["galleryViewer"]
    }),
    new HtmlWebpackPlugin({
      filename: "connectToGitHub.html",
      template: "src/connectToGitHub.html",
      chunks: ["connectToGitHub"]
    }),
    new MonacoWebpackPlugin(),
    new CopyWebpackPlugin({
      patterns: [{ from: "DataExplorer.nuspec" }, { from: "web.config" }, { from: "quickstart/*.zip" }]
    }),
    new EnvironmentPlugin(envVars)
  ];

  if (argv.analyze) {
    plugins.push(new BundleAnalyzerPlugin());
  }

  return {
    mode: mode,
    entry: {
      main: "./src/Main.tsx",
      index: "./src/Index.ts",
      quickstart: "./src/quickstart.ts",
      hostedExplorer: "./src/HostedExplorer.ts",
      heatmap: "./src/Controls/Heatmap/Heatmap.ts",
      terminal: "./src/Terminal/index.ts",
      notebookViewer: "./src/NotebookViewer/NotebookViewer.tsx",
      galleryViewer: "./src/GalleryViewer/GalleryViewer.tsx",
      connectToGitHub: "./src/GitHub/GitHubConnector.ts"
    },
    node: {
      util: true,
      tls: "empty",
      net: "empty"
    },
    output: {
      chunkFilename: "[name].[chunkhash:6].js",
      filename: "[name].[chunkhash:6].js",
      path: path.resolve(__dirname, "dist")
    },
    devtool: mode === "development" ? "cheap-eval-source-map" : "source-map",
    plugins,
    module: {
      rules
    },
    resolve: {
      extensions: [".tsx", ".ts", ".js"]
    },
    optimization: {
      minimize: mode === "production" ? true : false,
      minimizer: [
        new TerserPlugin({
          cache: ".cache/terser",
          terserOptions: {
            // These options increase our initial bundle size by ~5% but the builds are significantly faster and won't run out of memory
            compress: false,
            mangle: true
          }
        })
      ]
    },
    watch: isCI || mode === "production" ? false : true,
    // Hack since it is hard to disable watch entirely with webpack dev server https://github.com/webpack/webpack-dev-server/issues/1251#issuecomment-654240734
    watchOptions: isCI ? { poll: 24 * 60 * 60 * 1000 } : {},
    devServer: {
      hot: false,
      inline: !isCI,
      liveReload: !isCI,
      https: true,
      host: "0.0.0.0",
      port: envVars.PORT,
      stats: "minimal",
      headers: {
        "Access-Control-Allow-Origin": "*",
        "Access-Control-Allow-Credentials": "true",
        "Access-Control-Max-Age": "3600",
        "Access-Control-Allow-Headers": "*",
        "Access-Control-Allow-Methods": "*"
      },
      proxy: {
        "/api": {
          target: "https://main.documentdb.ext.azure.com",
          changeOrigin: true,
          logLevel: "debug",
          bypass: function(req, res, proxyOptions) {
            if (req.method === "OPTIONS") {
              res.statusCode = 200;
              res.send();
            }
          }
        },
        "/proxy": {
          target: "https://main.documentdb.ext.azure.com",
          changeOrigin: true,
          secure: false,
          logLevel: "debug",
          pathRewrite: { "^/proxy": "" },
          router: req => {
            let newTarget = req.headers["x-ms-proxy-target"];
            return newTarget;
          }
        },
        "/_explorer": {
          target: process.env.EMULATOR_ENDPOINT || "https://localhost:8081/",
          changeOrigin: true,
          secure: false,
          logLevel: "debug"
        },
        "/explorerProxy": {
          target: process.env.EMULATOR_ENDPOINT || "https://localhost:8081/",
          pathRewrite: { "^/explorerProxy": "" },
          changeOrigin: true,
          secure: false,
          logLevel: "debug"
        }
      }
    },
    stats: "minimal",
    node: {
      fs: "empty"
    }
  };
};