'use strict';
exports.__esModule = true;

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

/**
 * Derived significantly from package find-up@2.0.0. See license below.
 * 
 * @copyright Sindre Sorhus
 * MIT License
 *
 * Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com)
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
function findUp(filename, cwd) {
  let dir = path.resolve(cwd || '');
  const root = path.parse(dir).root;

  const filenames = [].concat(filename);

  // eslint-disable-next-line no-constant-condition
  while (true) {
    const file = filenames.find((el) => fs.existsSync(path.resolve(dir, el)));

    if (file) {
      return path.join(dir, file);
    }
    if (dir === root) {
      return null;
    }

    dir = path.dirname(dir);
  }
}

exports.default = function pkgUp(opts) {
  return findUp('package.json', opts && opts.cwd);
};