/**

 * 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

 */

import type {

  Request,

  ReactClientValue,

} from 'react-server/src/ReactFlightServer';

import type {Destination} from 'react-server/src/ReactServerStreamConfigNode';

import type {ClientManifest} from './ReactFlightServerConfigESMBundler';

import type {ServerManifest} from 'react-client/src/ReactFlightClientConfig';

import type {Busboy} from 'busboy';

import type {Writable} from 'stream';

import type {ServerContextJSONValue, Thenable} from 'shared/ReactTypes';

import {

  createRequest,

  startWork,

  startFlowing,

  stopFlowing,

  abort,

} from 'react-server/src/ReactFlightServer';

import {

  createResponse,

  reportGlobalError,

  close,

  resolveField,

  resolveFileInfo,

  resolveFileChunk,

  resolveFileComplete,

  getRoot,

} from 'react-server/src/ReactFlightReplyServer';

import {

  decodeAction,

  decodeFormState,

} from 'react-server/src/ReactFlightActionServer';

export {

  registerServerReference,

  registerClientReference,

} from './ReactFlightESMReferences';

function createDrainHandler(destination: Destination, request: Request) {

  return () => startFlowing(request, destination);

}

type Options = {

  onError?: (error: mixed) => void,

  onPostpone?: (reason: string) => void,

  context?: Array<[string, ServerContextJSONValue]>,

  identifierPrefix?: string,

};

type PipeableStream = {

  abort(reason: mixed): void,

  pipe<T: Writable>(destination: T): T,

};

function renderToPipeableStream(

  model: ReactClientValue,

  moduleBasePath: ClientManifest,

  options?: Options,

): PipeableStream {

  const request = createRequest(

    model,

    moduleBasePath,

    options ? options.onError : undefined,

    options ? options.context : undefined,

    options ? options.identifierPrefix : undefined,

    options ? options.onPostpone : undefined,

  );

  let hasStartedFlowing = false;

  startWork(request);

  return {

    pipe<T: Writable>(destination: T): T {

      if (hasStartedFlowing) {

        throw new Error(

          'React currently only supports piping to one writable stream.',

        );

      }

      hasStartedFlowing = true;

      startFlowing(request, destination);

      destination.on('drain', createDrainHandler(destination, request));

      return destination;

    },

    abort(reason: mixed) {

      stopFlowing(request);

      abort(request, reason);

    },

  };

}

function decodeReplyFromBusboy<T>(

  busboyStream: Busboy,

  moduleBasePath: ServerManifest,

): Thenable<T> {

  const response = createResponse(moduleBasePath, '');

  let pendingFiles = 0;

  const queuedFields: Array<string> = [];

  busboyStream.on('field', (name, value) => {

    if (pendingFiles > 0) {

      // Because the 'end' event fires two microtasks after the next 'field'

      // we would resolve files and fields out of order. To handle this properly

      // we queue any fields we receive until the previous file is done.

      queuedFields.push(name, value);

    } else {

      resolveField(response, name, value);

    }

  });

  busboyStream.on('file', (name, value, {filename, encoding, mimeType}) => {

    if (encoding.toLowerCase() === 'base64') {

      throw new Error(

        "React doesn't accept base64 encoded file uploads because we don't expect " +

          "form data passed from a browser to ever encode data that way. If that's " +

          'the wrong assumption, we can easily fix it.',

      );

    }

    pendingFiles++;

    const file = resolveFileInfo(response, name, filename, mimeType);

    value.on('data', chunk => {

      resolveFileChunk(response, file, chunk);

    });

    value.on('end', () => {

      resolveFileComplete(response, name, file);

      pendingFiles--;

      if (pendingFiles === 0) {

        // Release any queued fields

        for (let i = 0; i < queuedFields.length; i += 2) {

          resolveField(response, queuedFields[i], queuedFields[i + 1]);

        }

        queuedFields.length = 0;

      }

    });

  });

  busboyStream.on('finish', () => {

    close(response);

  });

  busboyStream.on('error', err => {

    reportGlobalError(

      response,

      // $FlowFixMe[incompatible-call] types Error and mixed are incompatible

      err,

    );

  });

  return getRoot(response);

}

function decodeReply<T>(

  body: string | FormData,

  moduleBasePath: ServerManifest,

): Thenable<T> {

  if (typeof body === 'string') {

    const form = new FormData();

    form.append('0', body);

    body = form;

  }

  const response = createResponse(moduleBasePath, '', body);

  const root = getRoot<T>(response);

  close(response);

  return root;

}

export {

  renderToPipeableStream,

  decodeReplyFromBusboy,

  decodeReply,

  decodeAction,

  decodeFormState,

};