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

    File: ECCx25519Public.cpp
    Date: 2021-9-17
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "ECC.hpp"
#include "ECCX25519Public.hpp"

namespace Aurora::Crypto::ECC
{
    PublicCurve25519Impl::PublicCurve25519Impl(bool isX25519, curve25519_key &&key) : key_(key), bIsX25519_(isX25519)
    {

    }

    PublicCurve25519Impl::~PublicCurve25519Impl()
    {
    }

    bool PublicCurve25519Impl::Verify(const Memory::MemoryViewRead &hash,
                                      const Memory::MemoryViewRead &signature)
    {
        int ok = 0;

        if (this->bIsX25519_)
        {
            return false;
        }

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

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

        auto iRet = ed25519_verify(AuReinterpretCast<const unsigned char *>(hash.ptr), hash.length,
                                   AuReinterpretCast<const unsigned char *>(signature.ptr), signature.length,
                                   &ok, &key_);
        if (iRet != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", iRet);
            return false;
        }

        return ok == 1;
    }

    bool PublicCurve25519Impl::Verify(const Memory::MemoryViewRead &plaintext,
                                      const Memory::MemoryViewRead &signature,
                                      AuHashing::EHashType method)
    {
        if (this->bIsX25519_)
        {
            return false;
        }
        
        if (!plaintext.HasMemory())
        {
            SysPushErrorParam();
            return {};
        }

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

        int hash = ::Crypto::HashMethodToId(method);
        if (hash == 0xFF)
        {
            SysPushErrorCrypt("invalid hash {}", method);
            return false;
        }

        AuByteBuffer hashVec;
        if (!AuTryResize(hashVec, 128))
        {
            SysPushErrorMem();
            return false;
        }

        unsigned long hashSize = hashVec.size();
        auto iRet = hash_memory(hash,
                                AuReinterpretCast<const unsigned char *>(plaintext.ptr), plaintext.length,
                                AuReinterpretCast<unsigned char *>(hashVec.data()), &hashSize);
        if (iRet != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", iRet);
            return false;
        }

        return Verify({hashVec}, signature);
    }

    bool PublicCurve25519Impl::AsPublicECC(Memory::ByteBuffer &out)
    {
        auto writeView = out.GetOrAllocateLinearWriteable(4096);
        if (!writeView)
        {
            SysPushErrorMem();
            return {};
        }

        unsigned long actualSize;
        int ret;

        actualSize = 4096;

        if (this->bIsX25519_)
        {
            ret = ::x25519_export(out.writePtr, &actualSize, PK_PUBLIC, &this->key_);
        }
        else
        {
            ret = ::ed25519_export(out.writePtr, &actualSize, PK_PUBLIC, &this->key_);
        }

        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", ret);
            return false;
        }

        out.writePtr += actualSize;

        return true;
    }

    EECCCurve PublicCurve25519Impl::GetType()
    {
        return this->bIsX25519_ ? EECCCurve::eCurveX25519 : EECCCurve::eCurveEd25519;
    }

    const curve25519_key &PublicCurve25519Impl::GetKey()
    {
        return this->key_;
    }
}