/*
* Copyright (c) 2013-2021, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/

#include <string.h>
#include "Log.h"
#include "Gost.h"
#include "CryptoKey.h"

namespace i2p {
    namespace crypto {
        ElGamalEncryptor::ElGamalEncryptor(const uint8_t *pub) {
            memcpy(m_PublicKey, pub, 256);
        }

        void ElGamalEncryptor::Encrypt(const uint8_t *data, uint8_t *encrypted) {
            ElGamalEncrypt(m_PublicKey, data, encrypted);
        }

        ElGamalDecryptor::ElGamalDecryptor(const uint8_t *priv) {
            memcpy(m_PrivateKey, priv, 256);
        }

        bool ElGamalDecryptor::Decrypt(const uint8_t *encrypted, uint8_t *data) {
            return ElGamalDecrypt(m_PrivateKey, encrypted, data);
        }

        ECIESP256Encryptor::ECIESP256Encryptor(const uint8_t *pub) {
            m_Curve = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
            m_PublicKey = EC_POINT_new(m_Curve);
            BIGNUM *x = BN_bin2bn(pub, 32, nullptr);
            BIGNUM *y = BN_bin2bn(pub + 32, 32, nullptr);
            if (!EC_POINT_set_affine_coordinates_GFp(m_Curve, m_PublicKey, x, y, nullptr))
                LogPrint(eLogError, "ECICS P256 invalid public key");
            BN_free(x);
            BN_free(y);
        }

        ECIESP256Encryptor::~ECIESP256Encryptor() {
            if (m_Curve) EC_GROUP_free(m_Curve);
            if (m_PublicKey) EC_POINT_free(m_PublicKey);
        }

        void ECIESP256Encryptor::Encrypt(const uint8_t *data, uint8_t *encrypted) {
            if (m_Curve && m_PublicKey)
                ECIESEncrypt(m_Curve, m_PublicKey, data, encrypted);
        }

        ECIESP256Decryptor::ECIESP256Decryptor(const uint8_t *priv) {
            m_Curve = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
            m_PrivateKey = BN_bin2bn(priv, 32, nullptr);
        }

        ECIESP256Decryptor::~ECIESP256Decryptor() {
            if (m_Curve) EC_GROUP_free(m_Curve);
            if (m_PrivateKey) BN_free(m_PrivateKey);
        }

        bool ECIESP256Decryptor::Decrypt(const uint8_t *encrypted, uint8_t *data) {
            if (m_Curve && m_PrivateKey)
                return ECIESDecrypt(m_Curve, m_PrivateKey, encrypted, data);
            return false;
        }

        void CreateECIESP256RandomKeys(uint8_t *priv, uint8_t *pub) {
            EC_GROUP *curve = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
            EC_POINT *p = nullptr;
            BIGNUM *key = nullptr;
            GenerateECIESKeyPair(curve, key, p);
            bn2buf(key, priv, 32);
            RAND_bytes(priv + 32, 224);
            BN_free(key);
            BIGNUM *x = BN_new(), *y = BN_new();
            EC_POINT_get_affine_coordinates_GFp(curve, p, x, y, NULL);
            bn2buf(x, pub, 32);
            bn2buf(y, pub + 32, 32);
            RAND_bytes(pub + 64, 192);
            EC_POINT_free(p);
            BN_free(x);
            BN_free(y);
            EC_GROUP_free(curve);
        }

        ECIESGOSTR3410Encryptor::ECIESGOSTR3410Encryptor(const uint8_t *pub) {
            auto &curve = GetGOSTR3410Curve(eGOSTR3410CryptoProA);
            m_PublicKey = EC_POINT_new(curve->GetGroup());
            BIGNUM *x = BN_bin2bn(pub, 32, nullptr);
            BIGNUM *y = BN_bin2bn(pub + 32, 32, nullptr);
            if (!EC_POINT_set_affine_coordinates_GFp(curve->GetGroup(), m_PublicKey, x, y, nullptr))
                LogPrint(eLogError, "ECICS GOST R 34.10 invalid public key");
            BN_free(x);
            BN_free(y);
        }

        ECIESGOSTR3410Encryptor::~ECIESGOSTR3410Encryptor() {
            if (m_PublicKey) EC_POINT_free(m_PublicKey);
        }

        void ECIESGOSTR3410Encryptor::Encrypt(const uint8_t *data, uint8_t *encrypted) {
            if (m_PublicKey)
                ECIESEncrypt(GetGOSTR3410Curve(eGOSTR3410CryptoProA)->GetGroup(), m_PublicKey, data, encrypted);
        }

        ECIESGOSTR3410Decryptor::ECIESGOSTR3410Decryptor(const uint8_t *priv) {
            m_PrivateKey = BN_bin2bn(priv, 32, nullptr);
        }

        ECIESGOSTR3410Decryptor::~ECIESGOSTR3410Decryptor() {
            if (m_PrivateKey) BN_free(m_PrivateKey);
        }

        bool ECIESGOSTR3410Decryptor::Decrypt(const uint8_t *encrypted, uint8_t *data) {
            if (m_PrivateKey)
                return ECIESDecrypt(GetGOSTR3410Curve(eGOSTR3410CryptoProA)->GetGroup(), m_PrivateKey, encrypted, data);
            return false;
        }


        void CreateECIESGOSTR3410RandomKeys(uint8_t *priv, uint8_t *pub) {
            auto &curve = GetGOSTR3410Curve(eGOSTR3410CryptoProA);
            EC_POINT *p = nullptr;
            BIGNUM *key = nullptr;
            GenerateECIESKeyPair(curve->GetGroup(), key, p);
            bn2buf(key, priv, 32);
            RAND_bytes(priv + 32, 224);
            BN_free(key);
            BIGNUM *x = BN_new(), *y = BN_new();
            EC_POINT_get_affine_coordinates_GFp(curve->GetGroup(), p, x, y, NULL);
            bn2buf(x, pub, 32);
            bn2buf(y, pub + 32, 32);
            RAND_bytes(pub + 64, 192);
            EC_POINT_free(p);
            BN_free(x);
            BN_free(y);
        }

        ECIESX25519AEADRatchetEncryptor::ECIESX25519AEADRatchetEncryptor(const uint8_t *pub) {
            memcpy(m_PublicKey, pub, 32);
        }

        void ECIESX25519AEADRatchetEncryptor::Encrypt(const uint8_t *, uint8_t *pub) {
            memcpy(pub, m_PublicKey, 32);
        }

        ECIESX25519AEADRatchetDecryptor::ECIESX25519AEADRatchetDecryptor(const uint8_t *priv, bool calculatePublic) {
            m_StaticKeys.SetPrivateKey(priv, calculatePublic);
        }

        bool ECIESX25519AEADRatchetDecryptor::Decrypt(const uint8_t *epub, uint8_t *sharedSecret) {
            return m_StaticKeys.Agree(epub, sharedSecret);
        }

        void CreateECIESX25519AEADRatchetRandomKeys(uint8_t *priv, uint8_t *pub) {
            X25519Keys k;
            k.GenerateKeys();
            k.GetPrivateKey(priv);
            memcpy(pub, k.GetPublicKey(), 32);
        }
    }
}