/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: ECCGeneric.cpp
    Date: 2021-9-17
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "ECC.hpp"
#include "ECCGeneric.hpp"
#include "ECCCurves.hpp"
#include "PrivateECCImpl.hpp"
#include "PublicECCImpl.hpp"

namespace Aurora::Crypto::ECC
{
    PrivateECCImpl::PrivateECCImpl(EECCCurve type, ecc_key &key) : _key(key)
    {

    }

    PrivateECCImpl::~PrivateECCImpl()
    {
        ecc_free(&_key);
    }

    EECCCurve PrivateECCImpl::GetType()
    {
        return _type;
    }

    bool PrivateECCImpl::Sign(const Memory::MemoryViewRead &plainText,
                              EHashType method,
                              AuList<AuUInt8> &out)
    {
        prng_state yarrow_prng;
        const int salt = 0;
        
        if (!plainText.HasMemory())
        {
            SysPushErrorParam();
            return {};
        }
        
        int hash = HashMethodToId(method);
        if (hash == 0xFF)
        {
            SysPushErrorCrypt("invalid hash {}", method);
            return false;
        }
        
        if (!AuTryResize(out, 1024))
        {
            SysPushErrorMem();
            return false;
        }
        
        AuList<AuUInt8> hashVec;
        
        if (!AuTryResize(hashVec, 128))
        {
            SysPushErrorMem();
            return false;
        }
        
        unsigned long hashSize = hashVec.size();
        auto ret = hash_memory(hash,
                               reinterpret_cast<const unsigned char *>(plainText.ptr), plainText.length,
                               reinterpret_cast<unsigned char *>(hashVec.data()), &hashSize);
        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", ret);
            return false;
        }
        
        return Sign(hashVec, out);
    }

    bool PrivateECCImpl::Sign(const Memory::MemoryViewRead &hash,
                              AuList<AuUInt8> &out)
    {
        prng_state yarrow_prng;
        const int salt = 0;

        if (!hash.HasMemory())
        {
            SysPushErrorParam();
            return {};
        }

        if (!AuTryResize(out, 1024))
        {
            SysPushErrorMem();
            return false;
        }

        unsigned long len = out.size();
        auto ret = ecc_sign_hash_ex(reinterpret_cast<const unsigned char *>(hash.ptr), hash.length,
                                    out.data(), &len,
                                    &yarrow_prng,
                                    ::Crypto::gPrngYarrow,
                                    LTC_ECCSIG_ETH27,
                                    nullptr,
                                    &_key);
        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", ret);
            return false;
        }
        
        if (!AuTryResize(out, len))
        {
            SysPushErrorMem();
            return false;
        }

        return true;
    }

    bool PrivateECCImpl::ECDH(const AuSPtr<IECCPublic> &partnerPublic,
                              AuList<AuUInt8> &sharedKey)
    {
        AuList<AuUInt8> sharedSecret;
        
        if (!AuTryResize(sharedSecret, 128))
        {
            SysPushErrorMem();
            return false;
        }
        
        if (partnerPublic->GetType() == this->GetType())
        {
            SysPushErrorCrypto("Can not EDCH with incompatible curve curve type (noting, ed25519 requires translation to x25519)");
            return false;
        }

        unsigned long actualSize = sharedSecret.size();
        auto ret = ecc_shared_secret(&_key, &(std::reinterpret_pointer_cast<PublicECCImpl>(partnerPublic)->GetKey()), sharedSecret.data(), &actualSize);
        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", ret);
            return false;
        }
        
        if (!AuTryResize(sharedSecret, actualSize))
        {
            SysPushErrorMem();
            return false;
        }
        
        return true;
    }

    bool PrivateECCImpl::AsPublicECC(AuList<AuUInt8> &out)
    {
        return ExportECCKey(_key, true, out);
    }

    bool PrivateECCImpl::AsPrivateECC(AuList<AuUInt8> &out)
    {
        return ExportECCKey(_key, false, out);
    }
}