<?php

declare(strict_types=1);

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2019 Spomky-Labs
 *
 * This software may be modified and distributed under the terms
 * of the MIT license.  See the LICENSE file for details.
 */

namespace Jose\Component\Signature\Algorithm;

use InvalidArgumentException;
use Jose\Component\Core\JWK;
use Jose\Component\Core\Util\ECKey;
use Jose\Component\Core\Util\ECSignature;
use LogicException;
use Throwable;

abstract class ECDSA implements SignatureAlgorithm
{
    public function __construct()
    {
        if (!\defined('OPENSSL_KEYTYPE_EC')) {
            throw new LogicException('Elliptic Curve key type not supported by your environment.');
        }
    }

    public function allowedKeyTypes(): array
    {
        return ['EC'];
    }

    public function sign(JWK $key, string $input): string
    {
        $this->checkKey($key);
        if (!$key->has('d')) {
            throw new InvalidArgumentException('The EC key is not private');
        }
        $pem = ECKey::convertPrivateKeyToPEM($key);
        openssl_sign($input, $signature, $pem, $this->getHashAlgorithm());

        return ECSignature::fromAsn1($signature, $this->getSignaturePartLength());
    }

    public function verify(JWK $key, string $input, string $signature): bool
    {
        $this->checkKey($key);

        try {
            $der = ECSignature::toAsn1($signature, $this->getSignaturePartLength());
            $pem = ECKey::convertPublicKeyToPEM($key);

            return 1 === openssl_verify($input, $der, $pem, $this->getHashAlgorithm());
        } catch (Throwable $e) {
            return false;
        }
    }

    abstract protected function getHashAlgorithm(): string;

    abstract protected function getSignaturePartLength(): int;

    private function checkKey(JWK $key): void
    {
        if (!\in_array($key->get('kty'), $this->allowedKeyTypes(), true)) {
            throw new InvalidArgumentException('Wrong key type.');
        }
        foreach (['x', 'y', 'crv'] as $k) {
            if (!$key->has($k)) {
                throw new InvalidArgumentException(sprintf('The key parameter "%s" is missing.', $k));
            }
        }
    }
}
