/**

 * Copyright (c) Meta Platforms, Inc. and affiliates.

 *

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

 *

 * @flow

 */

const acorn = require('acorn-loose');

const url = require('url');

const Module = require('module');

module.exports = function register() {

  const Server: any = require('react-server-dom-webpack/server');

  const registerServerReference = Server.registerServerReference;

  const createClientModuleProxy = Server.createClientModuleProxy;

  // $FlowFixMe[prop-missing] found when upgrading Flow

  const originalCompile = Module.prototype._compile;

  // $FlowFixMe[prop-missing] found when upgrading Flow

  Module.prototype._compile = function (

    this: any,

    content: string,

    filename: string,

  ): void {

    // Do a quick check for the exact string. If it doesn't exist, don't

    // bother parsing.

    if (

      content.indexOf('use client') === -1 &&

      content.indexOf('use server') === -1

    ) {

      return originalCompile.apply(this, arguments);

    }

    let body;

    try {

      body = acorn.parse(content, {

        ecmaVersion: '2024',

        sourceType: 'source',

      }).body;

    } catch (x) {

      // eslint-disable-next-line react-internal/no-production-logging

      console.error('Error parsing %s %s', url, x.message);

      return originalCompile.apply(this, arguments);

    }

    let useClient = false;

    let useServer = false;

    for (let i = 0; i < body.length; i++) {

      const node = body[i];

      if (node.type !== 'ExpressionStatement' || !node.directive) {

        break;

      }

      if (node.directive === 'use client') {

        useClient = true;

      }

      if (node.directive === 'use server') {

        useServer = true;

      }

    }

    if (!useClient && !useServer) {

      return originalCompile.apply(this, arguments);

    }

    if (useClient && useServer) {

      throw new Error(

        'Cannot have both "use client" and "use server" directives in the same file.',

      );

    }

    if (useClient) {

      const moduleId: string = (url.pathToFileURL(filename).href: any);

      this.exports = createClientModuleProxy(moduleId);

    }

    if (useServer) {

      originalCompile.apply(this, arguments);

      const moduleId: string = (url.pathToFileURL(filename).href: any);

      const exports = this.exports;

      // This module is imported server to server, but opts in to exposing functions by

      // reference. If there are any functions in the export.

      if (typeof exports === 'function') {

        // The module exports a function directly,

        registerServerReference(

          (exports: any),

          moduleId,

          // Represents the whole Module object instead of a particular import.

          null,

        );

      } else {

        const keys = Object.keys(exports);

        for (let i = 0; i < keys.length; i++) {

          const key = keys[i];

          const value = exports[keys[i]];

          if (typeof value === 'function') {

            registerServerReference((value: any), moduleId, key);

          }

        }

      }

    }

  };

};