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

    File: RSAPublic.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "../Crypto.hpp"
#include "RSA.hpp"
#include "RSAPublic.hpp"

namespace Aurora::Crypto::RSA
{
    PublicRSA::PublicRSA(rsa_key &key, bool owned) : key_(key), owned_(owned)
    {

    }

    PublicRSA::~PublicRSA()
    {
        if (this->owned_)
        {
            ::rsa_free(&this->key_);
        }
    }

    bool PublicRSA::Verify(const AuMemoryViewRead &payload,
                           const AuMemoryViewRead &signature,
                           EHashType method,
                           EPaddingType type)
    {
        
        if (!payload.HasMemory())
        {
            SysPushErrorParam();
            return {};
        }

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

        int padding = PaddingToType(type);
        if (padding == 0xFF)
        {
            SysPushErrorCrypt("invalid pad {}", type);
            return false;
        }

        int hash = 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 *>(payload.ptr), payload.length,
                                  AuReinterpretCast<unsigned char *>(hashVec.data()), &hashSize);
        if (iRet != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", iRet);
            return false;
        }


        int ok = 0;
        iRet = ::rsa_verify_hash_ex(AuReinterpretCast<const unsigned char *>(signature.ptr), signature.length,
                                    AuReinterpretCast<const unsigned char *>(hashVec.data()), hashSize,
                                    padding, hash, 0, &ok, &this->key_);
        if (iRet != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", iRet);
            return false;
        }

        return ok == 1;
    }

    bool PublicRSA::Encrypt(const Memory::MemoryViewRead &plainText,
                            EPaddingType type, 
                            AuMemory::ByteBuffer &out)
    {
        prng_state yarrow_prng;
        
        if (!plainText.HasMemory())
        {
            SysPushErrorParam();
            return {};
        }

        int padding = PaddingToType(type);
        if (padding == 0xFF)
        {
            SysPushErrorCrypt("invalid pad {}", type);
            return false;
        }

        const int prng_idx = padding == LTC_PKCS_1_PSS ? ::Crypto::gPrngYarrow : 0;
        if (prng_idx < 0)
        {
            SysPushErrorCrypt("{}", prng_idx);
            return false;
        }

        auto writeView = out.GetOrAllocateLinearWriteable(plainText.length + 1024);
        if (!writeView)
        {
            SysPushErrorMem();
            return {};
        }

        unsigned long len = out.size();

        auto iREt = ::rsa_encrypt_key_ex(AuReinterpretCast<const unsigned char *>(plainText.ptr), 
                                         plainText.length,
                                         out.writePtr, &len,
                                         NULL, 0,
                                         &yarrow_prng, prng_idx,
                                         0,
                                         padding,
                                         &this->key_);
        if (iREt != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", iREt);
            return false;
        }

        out.writePtr += len;
        return true;
    }

    bool PublicRSA::ToKey(ERSAKeyType type, AuByteBuffer &out)
    {
        return ExportRSAKey(this->key_, EKeyType::eKeyPublic, type, out);
    }

    AUKN_SYM IRSAPublic *OpenRSAPublicNew(const RSAKey &key)
    {
        rsa_key in {};

        if (!ImportRSAKey(in, key))
        {
            return nullptr;
        }

        auto pPublic = _new PublicRSA(in, true);
        if (!pPublic)
        {
            ::rsa_free(&in);
            return nullptr;
        }

        return pPublic;
    }

    AUKN_SYM void OpenRSAPublicRelease(IRSAPublic *pPublic)
    {
        AuSafeDelete<PublicRSA *>(pPublic);
    }
}