<?php

/**
 * PuTTY Formatted RSA Key Handler
 *
 * PHP version 8.1+
 *
 * @author    Jim Wigginton <terrafrost@php.net>
 * @copyright 2016-2026 Jim Wigginton
 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
 * @link      https://phpseclib.com/
 */

declare(strict_types=1);

namespace phpseclib4\Crypt\RSA\Formats\Keys;

use phpseclib4\Common\Functions\Strings;
use phpseclib4\Crypt\Common\Formats\Keys\PuTTY as Progenitor;
use phpseclib4\Exception\InvalidArgumentException;
use phpseclib4\Math\BigInteger;

/**
 * PuTTY Formatted RSA Key Handler
 *
 * @author  Jim Wigginton <terrafrost@php.net>
 * @psalm-api
 */
abstract class PuTTY extends Progenitor
{
    /**
     * Public Handler
     *
     * @var string
     */
    public const PUBLIC_HANDLER = OpenSSH::class;

    /**
     * Algorithm Identifier
     */
    protected static array $types = ['ssh-rsa'];

    /**
     * Break a public or private key down into its constituent components
     */
    public static function load(
        #[\SensitiveParameter] string $key,
        #[\SensitiveParameter] ?string $password
    ): array {
        static $one;
        if (!isset($one)) {
            $one = new BigInteger(1);
        }

        $components = parent::load($key, $password);
        if (!isset($components['private'])) {
            return $components;
        }
        [
            //'type' => $type,
            'comment' => $comment,
            'public' => $public,
            'private' => $private
        ] = $components;
        unset($components['public'], $components['private']);

        $isPublicKey = false;

        $primes = $coefficients = [];
        [$publicExponent, $modulus] = Strings::unpackSSH2('ii', $public);
        [$privateExponent, $primes[1], $primes[2], $coefficients[2]] = Strings::unpackSSH2('iiii', $private);

        $temp = $primes[1]->subtract($one);
        $exponents = [1 => $publicExponent->modInverse($temp)];
        $temp = $primes[2]->subtract($one);
        $exponents[] = $publicExponent->modInverse($temp);

        return compact('publicExponent', 'modulus', 'privateExponent', 'primes', 'coefficients', 'exponents', 'comment', 'isPublicKey');
    }

    /**
     * Convert a private key to the appropriate format.
     *
     * @psalm-suppress PossiblyUnusedParam
     */
    public static function savePrivateKey(
        BigInteger $n,
        BigInteger $e,
        #[\SensitiveParameter] BigInteger $d,
        #[\SensitiveParameter] array $primes,
        #[\SensitiveParameter] array $exponents,
        #[\SensitiveParameter] array $coefficients,
        #[\SensitiveParameter] ?string $password = null,
        array $options = []
    ): string {
        if (count($primes) != 2) {
            throw new InvalidArgumentException('PuTTY does not support multi-prime RSA keys');
        }

        $public =  Strings::packSSH2('ii', $e, $n);
        $private = Strings::packSSH2('iiii', $d, $primes[1], $primes[2], $coefficients[2]);

        return self::wrapPrivateKey($public, $private, 'ssh-rsa', $password, $options);
    }

    /**
     * Convert a public key to the appropriate format
     *
     * @psalm-suppress PossiblyUnusedParam
     */
    public static function savePublicKey(BigInteger $n, BigInteger $e, array $options = []): string
    {
        return self::wrapPublicKey(Strings::packSSH2('ii', $e, $n), 'ssh-rsa');
    }
}