<?php

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2016 Spomky-Labs
 *
 * This software may be modified and distributed under the terms
 * of the MIT license.  See the LICENSE file for details.
 */

namespace Jose\Factory;

use Assert\Assertion;
use Base64Url\Base64Url;
use Jose\KeyConverter\ECKey;
use Jose\KeyConverter\KeyConverter;
use Jose\KeyConverter\RSAKey;
use Jose\Object\JKUJWKSet;
use Jose\Object\JWK;
use Jose\Object\JWKSet;
use Jose\Object\JWKSetInterface;
use Jose\Object\JWKSets;
use Jose\Object\PublicJWKSet;
use Jose\Object\RotatableJWKSet;
use Jose\Object\StorableJWK;
use Jose\Object\StorableJWKSet;
use Jose\Object\X5UJWKSet;
use Mdanter\Ecc\Curves\CurveFactory;
use Mdanter\Ecc\Curves\NistCurve;
use Mdanter\Ecc\EccFactory;
use Psr\Cache\CacheItemPoolInterface;

final class JWKFactory implements JWKFactoryInterface
{
    /**
     * {@inheritdoc}
     */
    public static function createPublicKeySet(JWKSetInterface $jwkset)
    {
        return new PublicJWKSet($jwkset);
    }

    /**
     * {@inheritdoc}
     */
    public static function createKeySets(array $jwksets = [])
    {
        return new JWKSets($jwksets);
    }

    /**
     * {@inheritdoc}
     */
    public static function createStorableKey($filename, array $parameters)
    {
        return new StorableJWK($filename, $parameters);
    }

    /**
     * {@inheritdoc}
     */
    public static function createRotatableKeySet($filename, array $parameters, $nb_keys)
    {
        return new RotatableJWKSet($filename, $parameters, $nb_keys);
    }

    /**
     * {@inheritdoc}
     */
    public static function createStorableKeySet($filename, array $parameters, $nb_keys)
    {
        return new StorableJWKSet($filename, $parameters, $nb_keys);
    }

    /**
     * {@inheritdoc}
     */
    public static function createKey(array $config)
    {
        Assertion::keyExists($config, 'kty', 'The key "kty" must be set');
        $supported_types = ['RSA' => 'RSA', 'OKP' => 'OKP', 'EC' => 'EC', 'oct' => 'Oct', 'none' => 'None'];
        $kty = $config['kty'];
        Assertion::keyExists($supported_types, $kty, sprintf('The key type "%s" is not supported. Please use one of %s', $kty, json_encode(array_keys($supported_types))));
        $method = sprintf('create%sKey', $supported_types[$kty]);

        return self::$method($config);
    }

    /**
     * {@inheritdoc}
     */
    public static function createRSAKey(array $values)
    {
        Assertion::keyExists($values, 'size', 'The key size is not set.');
        $size = $values['size'];
        unset($values['size']);

        Assertion::true(0 === $size % 8, 'Invalid key size.');
        Assertion::greaterOrEqualThan($size, 384, 'Key length is too short. It needs to be at least 384 bits.');

        $key = openssl_pkey_new([
            'private_key_bits' => $size,
            'private_key_type' => OPENSSL_KEYTYPE_RSA,
        ]);
        openssl_pkey_export($key, $out);
        $rsa = new RSAKey($out);
        $values = array_merge(
            $values,
            $rsa->toArray()
        );

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createECKey(array $values)
    {
        Assertion::keyExists($values, 'crv', 'The curve is not set.');
        $curve = $values['crv'];
        if (function_exists('openssl_get_curve_names')) {
            $args = [
                'curve_name'       => self::getOpensslName($curve),
                'private_key_type' => OPENSSL_KEYTYPE_EC,
            ];
            $key = openssl_pkey_new($args);
            $res = openssl_pkey_export($key, $out);
            Assertion::true($res, 'Unable to create the key');

            $rsa = new ECKey($out);
            $values = array_merge(
                $values,
                $rsa->toArray()
            );

            return new JWK($values);
        } else {
            $curve_name = self::getNistName($curve);
            $generator = CurveFactory::getGeneratorByName($curve_name);
            $private_key = $generator->createPrivateKey();

            $values = array_merge(
                $values,
                [
                    'kty' => 'EC',
                    'crv' => $curve,
                    'x'   => self::encodeValue($private_key->getPublicKey()->getPoint()->getX()),
                    'y'   => self::encodeValue($private_key->getPublicKey()->getPoint()->getY()),
                    'd'   => self::encodeValue($private_key->getSecret()),
                ]
            );
        }

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createOctKey(array $values)
    {
        Assertion::keyExists($values, 'size', 'The key size is not set.');
        $size = $values['size'];
        unset($values['size']);
        Assertion::true(0 === $size % 8, 'Invalid key size.');
        $values = array_merge(
            $values,
            [
                'kty' => 'oct',
                'k'   => Base64Url::encode(random_bytes($size / 8)),
            ]
        );

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createOKPKey(array $values)
    {
        Assertion::keyExists($values, 'crv', 'The curve is not set.');
        $curve = $values['crv'];
        switch ($curve) {
            case 'X25519':
                Assertion::true(function_exists('curve25519_public'), sprintf('Unsupported "%s" curve', $curve));
                $d = random_bytes(32);
                $x = curve25519_public($d);
                break;
            case 'Ed25519':
                Assertion::true(function_exists('ed25519_publickey'), sprintf('Unsupported "%s" curve', $curve));
                $d = random_bytes(32);
                $x = ed25519_publickey($d);
                break;
            default:
                throw new \InvalidArgumentException(sprintf('Unsupported "%s" curve', $curve));
        }

        $values = array_merge(
            $values,
            [
                'kty' => 'OKP',
                'crv' => $curve,
                'x'   => Base64Url::encode($x),
                'd'   => Base64Url::encode($d),
            ]
        );

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createNoneKey(array $values)
    {
        $values = array_merge(
            $values,
            [
                'kty' => 'none',
                'alg' => 'none',
                'use' => 'sig',
            ]
        );

        return new JWK($values);
    }

    /**
     * @param string $value
     *
     * @return string
     */
    private static function encodeValue($value)
    {
        $value = gmp_strval($value);

        return Base64Url::encode(self::convertDecToBin($value));
    }

    /**
     * @param string $value
     *
     * @return string
     */
    private static function convertDecToBin($value)
    {
        $adapter = EccFactory::getAdapter();

        return hex2bin($adapter->decHex($value));
    }

    /**
     * @param string $curve
     *
     * @throws \InvalidArgumentException
     *
     * @return string
     */
    private static function getOpensslName($curve)
    {
        switch ($curve) {
            case 'P-256':
                return 'prime256v1';
            case 'P-384':
                return 'secp384r1';
            case 'P-521':
                return 'secp521r1';
            default:
                throw new \InvalidArgumentException(sprintf('The curve "%s" is not supported.', $curve));
        }
    }

    /**
     * @param string $curve
     *
     * @throws \InvalidArgumentException
     *
     * @return string
     */
    private static function getNistName($curve)
    {
        switch ($curve) {
            case 'P-256':
                return NistCurve::NAME_P256;
            case 'P-384':
                return NistCurve::NAME_P384;
            case 'P-521':
                return NistCurve::NAME_P521;
            default:
                throw new \InvalidArgumentException(sprintf('The curve "%s" is not supported.', $curve));
        }
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromValues(array $values)
    {
        if (array_key_exists('keys', $values) && is_array($values['keys'])) {
            return new JWKSet($values);
        }

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromCertificateFile($file, array $additional_values = [])
    {
        $values = KeyConverter::loadKeyFromCertificateFile($file);
        $values = array_merge($values, $additional_values);

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromCertificate($certificate, array $additional_values = [])
    {
        $values = KeyConverter::loadKeyFromCertificate($certificate);
        $values = array_merge($values, $additional_values);

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromX509Resource($res, array $additional_values = [])
    {
        $values = KeyConverter::loadKeyFromX509Resource($res);
        $values = array_merge($values, $additional_values);

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromKeyFile($file, $password = null, array $additional_values = [])
    {
        $values = KeyConverter::loadFromKeyFile($file, $password);
        $values = array_merge($values, $additional_values);

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromKey($key, $password = null, array $additional_values = [])
    {
        $values = KeyConverter::loadFromKey($key, $password);
        $values = array_merge($values, $additional_values);

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromJKU($jku, $allow_unsecured_connection = false, CacheItemPoolInterface $cache = null, $ttl = 86400, $allow_http_connection = false)
    {
        return new JKUJWKSet($jku, $cache, $ttl, $allow_unsecured_connection, $allow_http_connection);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromX5U($x5u, $allow_unsecured_connection = false, CacheItemPoolInterface $cache = null, $ttl = 86400, $allow_http_connection = false)
    {
        return new X5UJWKSet($x5u, $cache, $ttl, $allow_unsecured_connection, $allow_http_connection);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromX5C(array $x5c, array $additional_values = [])
    {
        $values = KeyConverter::loadFromX5C($x5c);
        $values = array_merge($values, $additional_values);

        return new JWK($values);
    }

    /**
     * {@inheritdoc}
     */
    public static function createFromKeySet(JWKSetInterface $jwk_set, $key_index)
    {
        Assertion::integer($key_index);

        return $jwk_set->getKey($key_index);
    }
}
