<?php
/**
* Copyright since 2023 Waynet Sp. z o.o.
*
* NOTICE OF LICENSE
*
* This source file is subject to the Open Software License (OSL 3.0)
* that is bundled with this package in the file LICENSE.md.
* It is also available through the world-wide-web at this URL:
* https://opensource.org/licenses/OSL-3.0
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to kontakt@waynet.pl so we can send you a copy immediately.
*
* @author    Waynet Sp. z o.o. <kontakt@waynet.pl>
* @copyright since 2023 Waynet Sp. z o.o.
* @license   https://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
*/

declare(strict_types=1);

namespace Waynet\OAuth2\Client\PKCE;

abstract class PkceMethod implements PkceMethodInterface
{
    private $codeVerifier;

    public function getCodeVerifier(): string
    {
        if (!isset($this->codeVerifier)) {
            $this->codeVerifier = $this->base64UrlEncode(random_bytes(64));
        }

        return $this->codeVerifier;
    }

    protected function base64UrlEncode(string $data): string
    {
        return str_replace('=', '', strtr(base64_encode($data), '+/', '-_'));
    }
}