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

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

#include "ECCX25519Public.hpp"
#include "ECCX25519Private.hpp"

extern "C" int x509_decode_subject_public_key_info_2(const unsigned char *in, unsigned long inlen,
                                                     const unsigned long *oid,
                                                     void *parameters, unsigned long *parameters_len);
namespace Aurora::Crypto::ECC
{
    static bool IsKeyGeneric(const void *ptr, AuUInt length, AuArray<unsigned long, 16> &curveOidm, unsigned long &oidLen)
    {
        const unsigned long oid[16]
        {
            1, 2, 840, 10045, 2, 1,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0
        };

        return x509_decode_subject_public_key_info_2((const unsigned char *)ptr, length, oid, curveOidm.data(), &oidLen) == CRYPT_OK;
    }

    static EECCCurve GetEdECCCurveType(const void *ptr, AuUInt length)
    {
        AuArray<unsigned long, 16> ec;
        unsigned long ecLen;

        if (IsKeyGeneric(ptr, length, ec, ecLen))
        {
            return OIDToCurve(ec.data(), ecLen);
        }

        return EECCCurve::kEnumInvalid;
    }

    static bool IsBlobCurveX25519(const void *ptr, AuUInt length)
    {
        const unsigned long oidX25519[16]
        {
            1, 3, 101, 110,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
        };

        return x509_decode_subject_public_key_info_2((const unsigned char *)ptr, length, oidX25519, NULL, 0) == CRYPT_OK;
    }

    static bool IsBlobCurveEd25519(const void *ptr, AuUInt length)
    {
        const unsigned long oidEd25519[16]
        {
            1, 3, 101, 112,
            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
        };

        return x509_decode_subject_public_key_info_2((const unsigned char *)ptr, length, oidEd25519, NULL, 0) == CRYPT_OK;
    }

    template<bool IsPublic, typename T>
    static T New25519ECC(bool isX25519, const Memory::MemoryViewRead &pk, bool cert = false)
    {
        curve25519_key in {};
        int ret;

        if (cert)
        {
            if (!IsPublic)
            {
                SysPushErrorArg();
                return nullptr;
            }

            ret = isX25519 ? x25519_import_x509(pk.Begin<const unsigned char>(), pk.length, &in) : ed25519_import_x509(pk.Begin<const unsigned char>(), pk.length, &in);
        }
        else
        {
            constexpr auto type = IsPublic ? PK_PUBLIC : PK_PRIVATE;
            ret = isX25519 ? x25519_import_raw(pk.Begin<const unsigned char>(), pk.length, type, &in) : ed25519_import_raw(pk.Begin<const unsigned char>(), pk.length, type, &in);
        }

        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypto("{}", ret);
            return nullptr;
        }

        if constexpr (IsPublic)
        {
            return _new PublicCurve25519Impl(isX25519, AuMove(in));
        }
        else
        {
            return _new PrivateCurve25519Impl(isX25519, AuMove(in));
        }
    }

    static IECCPrivate *Gen25519ECC(bool isX25519)
    {
        curve25519_key in {};
        int ret;
        const int prng_idx = register_prng(&sprng_desc);

        ret = isX25519 ? x25519_make_key(NULL, prng_idx, &in) : ed25519_make_key(NULL, prng_idx, &in);
        if (ret != CRYPT_OK)
        {
            SysPushErrorCrypto("{}", ret);
            return nullptr;
        }

        return _new PrivateCurve25519Impl(isX25519, AuMove(in));
    }

    static void ReleasePublicECC(IECCPublic *pub)
    {
        switch (pub->GetType())
        {
        case EECCCurve::eCurveEd25519:
        case EECCCurve::eCurveX25519:
            AuSafeDelete<PublicCurve25519Impl *>(pub);
            return;
        default:
            AuSafeDelete<PublicECCImpl *>(pub);
            return;
        }
    }
    
    static void ReleasePrivateECC(IECCPrivate *priv)
    {
        switch (priv->GetType())
        {
        case EECCCurve::eCurveEd25519:
        case EECCCurve::eCurveX25519:
            AuSafeDelete<PrivateCurve25519Impl *>(priv);
            return;
        default:
            AuSafeDelete<PrivateECCImpl *>(priv);
            return;
        }
    }

    AUKN_SYM IECCPrivate *NewECC(EECCCurve curve)
    {
        switch (curve)
        {
        case EECCCurve::eCurveEd25519:
            return Gen25519ECC(false);
        case EECCCurve::eCurveX25519:
            return Gen25519ECC(true);
        default:
            return GenerateNewGenericECC(curve).value_or(nullptr);
        }
    }

    AUKN_SYM IECCPrivate *OpenPrivateECC(const AuMemoryViewRead &pk)
    {
        auto type = GetEdECCCurveType(pk.ptr, pk.length);
        if (type != EECCCurve::eEnumInvalid)
        {
            if (auto ret = NewStdECC<PrivateECCImpl>(type, pk, false))
            {
                return ret;
            }
        }

        if (IsBlobCurveX25519(pk.ptr, pk.length))
        {
            return New25519ECC<false, IECCPrivate*>(true, pk, false);
        }

        if (IsBlobCurveEd25519(pk.ptr, pk.length))
        {
            return New25519ECC<false, IECCPrivate *>(false, pk, false);
        }

        return {};
    }

    AUKN_SYM IECCPublic *OpenPublicECC(const AuMemoryViewRead &pk)
    {
        auto type = GetEdECCCurveType(pk.ptr, pk.length);
        if (type != EECCCurve::eEnumInvalid)
        {
            if (auto ret = NewStdECC<PublicECCImpl>(type, pk, false))
            {
                return ret;
            }
        }
        
        if (IsBlobCurveX25519(pk.ptr, pk.length))
        {
            return New25519ECC<true, IECCPublic *>(true, pk, false);
        }

        if (IsBlobCurveEd25519(pk.ptr, pk.length))
        {
            return New25519ECC<true, IECCPublic *>(false, pk, false);
        }

        return {};
    }

    AUKN_SYM IECCPublic *OpenPublicECCFromCert(const AuMemoryViewRead &certificate)
    {
        auto type = GetEdECCCurveType(certificate.ptr, certificate.length);
        if (type != EECCCurve::eEnumInvalid)
        {
            if (auto ret = NewStdECC<PublicECCImpl>(type, certificate, true))
            {
                return ret;
            }
        }

        if (IsBlobCurveX25519(certificate.ptr, certificate.length))
        {
            return New25519ECC<true, IECCPublic *>(true, certificate, true);
        }

        if (IsBlobCurveEd25519(certificate.ptr, certificate.length))
        {
            return New25519ECC<true, IECCPublic *>(false, certificate, true);
        }
        
        return {};
    }
    
    AUKN_SYM void NewECCRelease(IECCPrivate *priv)
    {
        ReleasePrivateECC(priv);
    }

    AUKN_SYM void OpenPrivateECCRelease(IECCPrivate *priv)
    {
        ReleasePrivateECC(priv);
    }

    AUKN_SYM void OpenPublicECCRelease(IECCPublic *pub)
    {
        ReleasePublicECC(pub);
    }

    AUKN_SYM void OpenPublicECCFromCertRelease(IECCPublic *pub)
    {
        ReleasePublicECC(pub);
    }
}