/***
    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"

namespace Aurora::Crypto::ECC
{
    int pk_oid_str_to_num(const char *OID, unsigned long *oid, unsigned long *oidlen)
    {
        unsigned long i, j, limit, oid_j;
        size_t OID_len;

        LTC_ARGCHK(oidlen != NULL);

        limit = *oidlen;
        *oidlen = 0; /* make sure that we return zero oidlen on error */
        for (i = 0; i < limit; i++) oid[i] = 0;

        if (OID == NULL) return CRYPT_OK;

        OID_len = XSTRLEN(OID);
        if (OID_len == 0) return CRYPT_OK;

        for (i = 0, j = 0; i < OID_len; i++)
        {
            if (OID[i] == '.')
            {
                if (++j >= limit) continue;
            }
            else if ((OID[i] >= '0') && (OID[i] <= '9'))
            {
                if ((j >= limit) || (oid == NULL)) continue;
                oid_j = oid[j];
                oid[j] = oid[j] * 10 + (OID[i] - '0');
                if (oid[j] < oid_j) return CRYPT_OVERFLOW;
            }
            else
            {
                return CRYPT_ERROR;
            }
        }
        if (j == 0) return CRYPT_ERROR;
        if (j >= limit)
        {
            *oidlen = j;
            return CRYPT_BUFFER_OVERFLOW;
        }
        *oidlen = j + 1;
        return CRYPT_OK;
    }

    int pk_oid_num_to_str(const unsigned long *oid, unsigned long oidlen, char *OID, unsigned long *outlen)
    {
        int i;
        unsigned long j, k;
        char tmp[256] = {0};

        LTC_ARGCHK(oid != NULL);
        LTC_ARGCHK(OID != NULL);
        LTC_ARGCHK(outlen != NULL);

        for (i = oidlen - 1, k = 0; i >= 0; i--)
        {
            j = oid[i];
            if (j == 0)
            {
                tmp[k] = '0';
                if (++k >= sizeof(tmp)) return CRYPT_ERROR;
            }
            else
            {
                while (j > 0)
                {
                    tmp[k] = '0' + (j % 10);
                    if (++k >= sizeof(tmp)) return CRYPT_ERROR;
                    j /= 10;
                }
            }
            if (i > 0)
            {
                tmp[k] = '.';
                if (++k >= sizeof(tmp)) return CRYPT_ERROR;
            }
        }
        if (*outlen < k + 1)
        {
            *outlen = k + 1;
            return CRYPT_BUFFER_OVERFLOW;
        }
        for (j = 0; j < k; j++) OID[j] = tmp[k - j - 1];
        OID[k] = '\0';
        *outlen = k; /* the length without terminating NUL byte */
        return CRYPT_OK;
    }

    bool ExportECCKey(const ecc_key &key, bool pub, DerBuffer &out)
    {
        auto writeView = out.GetOrAllocateLinearWriteable(4096);
        if (!writeView)
        {
            SysPushErrorMem();
            return {};
        }

        unsigned long actualSize = 4096;
        auto iRet = ::ecc_export_openssl(out.writePtr,
                                         &actualSize, PK_CURVEOID | (pub ? PK_PUBLIC : PK_PRIVATE),
                                         &key);

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

        out.writePtr +=actualSize;

        return true;
    }

    AuOptional<IECCPrivate *> GenerateNewGenericECC(EECCCurve curve)
    {
        ecc_key key = {};
        const int prng_idx = register_prng(&sprng_desc);
        prng_state yarrow_prng;

        auto tc = GetECCCurve(curve);
        if (!tc)
        {
            SysPushErrorCrypt();
            return {};
        }

        auto error = ecc_make_key_ex(&yarrow_prng, prng_idx, &key, *tc);
        if (error != CRYPT_OK)
        {
            SysPushErrorCrypt("{}", error);
            return {};
        }

        auto ret = _new PrivateECCImpl(curve, key);
        if (!ret)
        {
            ecc_free(&key);
            SysPushErrorMem();
            return {};
        }

        return ret;
    }
}