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

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

namespace Aurora::Crypto::RSA
{
    PrivateRSA::PrivateRSA(rsa_key &key) : key_(key)
    {

    }

    PrivateRSA::~PrivateRSA()
    {
        rsa_free(&key_);
    }

    bool PrivateRSA::Sign(const Memory::MemoryViewRead & payload,
                          EHashType method,
                          EPaddingType type,
                          AuList<AuUInt8> &out)
    {
        prng_state yarrow_prng;
        const int salt = 0;
        
        if (!payload.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;
        }

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

        unsigned long len = out.size();
        ret = rsa_sign_hash_ex(reinterpret_cast<const unsigned char *>(hashVec.data()), hashSize,
                               out.data(), &len,
                               padding,
                               &yarrow_prng,
                               ::Crypto::gPrngYarrow,
                               hash,
                               salt,
                               &key_);
        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", ret);
            return false;
        }

        out.resize(len);
        return true;
    }

    bool PrivateRSA::Decrypt(const Memory::MemoryViewRead &payload, 
                             EPaddingType type, 
                             AuList<AuUInt8> &out)
    {
        if (!payload.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;
        }

        if (!AuTryResize(out, payload.length))
        {
            SysPushErrorMem();
            return false;
        }

        unsigned long len = out.size();

        int stat = 0;
        auto ret = rsa_decrypt_key_ex(reinterpret_cast<const unsigned char *>(payload.ptr), payload.length,
                                      out.data(), &len,
                                      NULL, 0,
                                      0, // hash? excuse me?
                                      padding,
                                      &stat,
                                      &key_);
        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", ret);
            return false;
        }

        out.resize(len);
        return stat == 1;
    }

    AuSPtr<IRSAPublic> PrivateRSA::ToPublic()
    {
        return AuMakeShared<PublicRSA>(key_, false);
    }

    bool PrivateRSA::ToKey(const RSAMeta &meta, AuList<AuUInt8> &out)
    {
        return ExportRSAKey(key_, meta.side, meta.type, out);
    }

    AUKN_SYM IRSAPrivate *OpenRSAPrivateNew(const RSAKey &key)
    {
        rsa_key in {};

        if (key.meta.side == EKeyType::eKeyPublic)
        {
            SysPushErrorArg("Attempted to import a public key as a private key.");
            return nullptr;
        }

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

        auto ret = _new PrivateRSA(in);
        if (!ret)
        {
            rsa_free(&in);
            return nullptr;
        }

        return ret;
    }

    AUKN_SYM void OpenRSAPrivateRelease(IRSAPrivate *re)
    {
        SafeDelete<PrivateRSA *>(re);
    }

    AUKN_SYM IRSAPrivate *NewRSAKeyNew(AuUInt16 keySize)
    {
        prng_state yarrow_prng {};
        rsa_key key {};
        const int prng_idx = register_prng(&sprng_desc);

        auto error = rsa_make_key(NULL, prng_idx, keySize / 8, 65537, &key);
        if (error != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", error);
            return nullptr;
        }

        auto ret = _new PrivateRSA(key);
        if (!ret)
        {
            rsa_free(&key);
            return nullptr;
        }

        return ret;
    }

    AUKN_SYM void NewRSAKeyRelease(IRSAPrivate *re)
    {
        return OpenRSAPrivateRelease(re);
    }
}