"use strict";

const errorOverlayMiddleware = require("react-dev-utils/errorOverlayMiddleware");
const evalSourceMapMiddleware = require("react-dev-utils/evalSourceMapMiddleware");
const noopServiceWorkerMiddleware = require("react-dev-utils/noopServiceWorkerMiddleware");
const ignoredFiles = require("react-dev-utils/ignoredFiles");
const paths = require("./paths");
const fs = require("fs");

const protocol = process.env.HTTPS === "true" ? "https" : "http";
const host = process.env.HOST || "0.0.0.0";

module.exports = function (proxy, allowedHost) {
    return {
        // WebpackDevServer 2.4.3 introduced a security fix that prevents remote
        // websites from potentially accessing local content through DNS rebinding:
        // https://github.com/webpack/webpack-dev-server/issues/887
        // https://medium.com/webpack/webpack-dev-server-middleware-security-issues-1489d950874a
        // However, it made several existing use cases such as development in cloud
        // environment or subdomains in development significantly more complicated:
        // https://github.com/facebook/create-react-app/issues/2271
        // https://github.com/facebook/create-react-app/issues/2233
        // While we're investigating better solutions, for now we will take a
        // compromise. Since our WDS configuration only serves files in the `public`
        // folder we won't consider accessing them a vulnerability. However, if you
        // use the `proxy` feature, it gets more dangerous because it can expose
        // remote code execution vulnerabilities in backends like Django and Rails.
        // So we will disable the host check normally, but enable it if you have
        // specified the `proxy` setting. Finally, we let you override it if you
        // really know what you're doing with a special environment variable.
        disableHostCheck:
            !proxy || process.env.DANGEROUSLY_DISABLE_HOST_CHECK === "true",
        // Enable gzip compression of generated files.
        compress: true,
        // Silence WebpackDevServer's own logs since they're generally not useful.
        // It will still show compile warnings and errors with this setting.
        clientLogLevel: "none",
        // By default WebpackDevServer serves physical files from current directory
        // in addition to all the virtual build products that it serves from memory.
        // This is confusing because those files won’t automatically be available in
        // production build folder unless we copy them. However, copying the whole
        // project directory is dangerous because we may expose sensitive files.
        // Instead, we establish a convention that only files in `public` directory
        // get served. Our build script will copy `public` into the `build` folder.
        // In `index.html`, you can get URL of `public` folder with %PUBLIC_URL%:
        // <link rel="icon" href="%PUBLIC_URL%/favicon.ico">
        // In JavaScript code, you can access it with `process.env.PUBLIC_URL`.
        // Note that we only recommend to use `public` folder as an escape hatch
        // for files like `favicon.ico`, `manifest.json`, and libraries that are
        // for some reason broken when imported through Webpack. If you just want to
        // use an image, put it in `src` and `import` it from JavaScript instead.
        contentBase: paths.appPublic,
        // By default files from `contentBase` will not trigger a page reload.
        watchContentBase: true,
        // Enable hot reloading server. It will provide /sockjs-node/ endpoint
        // for the WebpackDevServer client so it can learn when the files were
        // updated. The WebpackDevServer client is included as an entry point
        // in the Webpack development configuration. Note that only changes
        // to CSS are currently hot reloaded. JS changes will refresh the browser.
        hot: true,
        // It is important to tell WebpackDevServer to use the same "root" path
        // as we specified in the config. In development, we always serve from /.
        publicPath: "/",
        // WebpackDevServer is noisy by default so we emit custom message instead
        // by listening to the compiler events with `compiler.hooks[...].tap` calls above.
        quiet: true,
        // Reportedly, this avoids CPU overload on some systems.
        // https://github.com/facebook/create-react-app/issues/293
        // src/node_modules is not ignored to support absolute imports
        // https://github.com/facebook/create-react-app/issues/1065
        watchOptions: {
            ignored: ignoredFiles(paths.appSrc),
        },
        // Enable HTTPS if the HTTPS environment variable is set to 'true'
        https: protocol === "https",
        host,
        overlay: false,
        historyApiFallback: {
            // Paths with dots should still use the history fallback.
            // See https://github.com/facebook/create-react-app/issues/387.
            disableDotRule: true,
        },
        public: allowedHost,
        proxy,
        before(app, server) {
            if (fs.existsSync(paths.proxySetup)) {
                // This registers user provided middleware for proxy reasons
                require(paths.proxySetup)(app);
            }

            // This lets us fetch source contents from webpack for the error overlay
            app.use(evalSourceMapMiddleware(server));
            // This lets us open files from the runtime error overlay.
            app.use(errorOverlayMiddleware());

            // This service worker file is effectively a 'no-op' that will reset any
            // previous service worker registered for the same host:port combination.
            // We do this in development to avoid hitting the production cache if
            // it used the same host and port.
            // https://github.com/facebook/create-react-app/issues/2272#issuecomment-302832432
            app.use(noopServiceWorkerMiddleware("/"));
        },
    };
};
