Config.php

<?php

/*
 * PHP script for downloading videos from youtube
 * Copyright (C) 2012-2018  John Eckman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, see <http://www.gnu.org/licenses/>.
 */

namespace YoutubeDownloader;

/**
 * Config class
 */
class Config
{
    /**
     * Creates the config from files
     *
     * @param string $default full path to default config php file
     * @param string $custom  full path to custom config php file
     *
     * @return Config
     */
    public static function createFromFiles($default, $custom = null)
    {
        $default_config = require($default);
        $custom_config = [];

        if (file_exists($custom)) {
            $custom_config = require($custom);
        }

        $config = array_replace_recursive($default_config, $custom_config);

        return new self($config);
    }

    private $data = [];

    private $allowed_keys = [
        'enable_youtube_decipher_signature',
        'ThumbnailImageMode',
        'localCache',
        'VideoLinkMode',
        'MP3Enable',
        'MP3ConvertVideo',
        'MP3Quality',
        'MP3TempDir',
        'ffmpegPath',
        'aria2Path',
        'showBrowserExtensions',
        'multipleIPs',
        'IPs',
        'default_timezone',
        'debug',
    ];

    /**
     * Creates a Config from an array
     *
     * @param array $config
     *
     * @return self
     */
    private function __construct(array $config)
    {
        foreach ($this->allowed_keys as $key) {
            if (array_key_exists($key, $config)) {
                $this->data[$key] = $config[$key];
            }
        }
    }

    /**
     * Get a config value
     *
     * @param string $key
     *
     * @return mixed
     */
    public function get($key)
    {
        if (array_key_exists($key, $this->data)) {
            return $this->data[$key];
        }

        throw new \InvalidArgumentException;
    }
}