/**
 * Copyright (c) Facebook, Inc. and its 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 {Destination} from './ReactFizzHostConfig';
import type {ReactNodeList} from 'shared/ReactTypes';

import {
 scheduleWork,
 beginWriting,
 writeChunk,
 completeWriting,
 flushBuffered,
 close,
} from './ReactFizzHostConfig';
import {formatChunk} from './ReactFizzFormatConfig';
import {REACT_ELEMENT_TYPE} from 'shared/ReactSymbols';

type OpaqueRequest = {
 destination: Destination,
 children: ReactNodeList,
 completedChunks: Array<Uint8Array>,
 flowing: boolean,
};

export function createRequest(
 children: ReactNodeList,
 destination: Destination,
): OpaqueRequest {
 return {destination, children, completedChunks: [], flowing: false};
}

function performWork(request: OpaqueRequest): void {
 let element = (request.children: any);
 request.children = null;
 if (element && element.$$typeof !== REACT_ELEMENT_TYPE) {
 return;
 }
 let type = element.type;
 let props = element.props;
 if (typeof type !== 'string') {
 return;
 }
 request.completedChunks.push(formatChunk(type, props));
 if (request.flowing) {
 flushCompletedChunks(request);
 }

 flushBuffered(request.destination);
}

function flushCompletedChunks(request: OpaqueRequest) {
 let destination = request.destination;
 let chunks = request.completedChunks;
 request.completedChunks = [];

 beginWriting(destination);
 try {
 for (let i = 0; i < chunks.length; i++) {
 let chunk = chunks[i];
 writeChunk(destination, chunk);
 }
 } finally {
 completeWriting(destination);
 }
 close(destination);
}

export function startWork(request: OpaqueRequest): void {
 request.flowing = true;
 scheduleWork(() => performWork(request));
}

export function startFlowing(
 request: OpaqueRequest,
 desiredBytes: number,
): void {
 request.flowing = false;
 flushCompletedChunks(request);
}