/**
 * 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
 * @format
 */

'use strict';

const crypto = require('crypto');
const fs = require('fs');

function getKeyFromFile(filePath: string): string {
  return createHash(fs.readFileSync(filePath));
}

function createHash(str: string | Buffer): string {
  return crypto
    .createHash('sha1')
    .update(str)
    .digest('hex');
}

module.exports = function getKeyFromFiles(files: $ReadOnlyArray<string>) {
  return createHash(files.map(getKeyFromFile).join('$'));
};