// Copyright © 2017-2020 Trust Wallet.

//

// This file is part of Trust. The full Trust copyright notice, including

// terms governing use, modification, and redistribution, is contained in the

// file LICENSE at the root of the source code distribution tree.

#include "Signer.h"

#include "../HexCoding.h"

#include <TrezorCrypto/ecdsa.h>

#include <TrezorCrypto/secp256k1.h>

#include <TrezorCrypto/nist256p1.h>

using namespace TW;

using namespace TW::EOS;

void Signer::sign(const PrivateKey& privateKey, Type type, Transaction& transaction) const {

if (!transaction.isValid()) {

throw std::invalid_argument("Invalid transaction!");;

}

// values for Legacy and ModernK1

TWCurve curve = TWCurveSECP256k1;

auto canonicalChecker = is_canonical;

// Values for ModernR1

if (type == Type::ModernR1) {

curve = TWCurveNIST256p1;

canonicalChecker = nullptr;

}

const Data result = privateKey.sign(hash(transaction), curve, canonicalChecker);

transaction.signatures.push_back(Signature(result, type));

}

TW::Data Signer::hash(const Transaction& transaction) const noexcept {

Data hashInput(chainID);

transaction.serialize(hashInput);

Data cfdHash(Hash::sha256Size); // default value for empty cfd

if (transaction.contextFreeData.size()) {

cfdHash = Hash::sha256(transaction.contextFreeData);

}

append(hashInput, cfdHash);

return Hash::sha256(hashInput);

}

// canonical check for EOS

int Signer::is_canonical(uint8_t by, uint8_t sig[64]) {

return !(sig[0] & 0x80)

&& !(sig[0] == 0 && !(sig[1] & 0x80))

&& !(sig[32] & 0x80)

&& !(sig[32] == 0 && !(sig[33] & 0x80));

}