// 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 "Address.h"

#include "Base58.h"

#include "Base64.h"

#include "HexCoding.h"

#include "Identifiers.h"

#include <Data.h>

#include <Ethereum/RLP.h>

using namespace TW;

using namespace TW::Aeternity;

/// implementation copied from

/// https://github.com/aeternity/aepp-sdk-go/blob/07aa8a77e5/aeternity/helpers.go#L367

Proto::SigningOutput Signer::sign(const TW::PrivateKey &privateKey, Transaction &transaction) {

auto txRlp = transaction.encode();

/// append networkId and txRaw

auto msg = buildMessageToSign(txRlp);

/// sign ed25519

auto sigRaw = privateKey.sign(msg, TWCurveED25519);

auto signature = Identifiers::prefixSignature + Base58::bitcoin.encodeCheck(sigRaw);

/// encode the message using rlp

auto rlpTxRaw = buildRlpTxRaw(txRlp, sigRaw);

/// encode the rlp message with the prefix

auto signedEncodedTx = encodeBase64WithChecksum(Identifiers::prefixTransaction, rlpTxRaw);

return createProtoOutput(signature, signedEncodedTx);

}

Data Signer::buildRlpTxRaw(Data &txRaw, Data &sigRaw) {

auto rlpTxRaw = Data();

auto signaturesList = Data();

append(signaturesList, Ethereum::RLP::encode(sigRaw));

append(rlpTxRaw, Ethereum::RLP::encode(Identifiers::objectTagSignedTransaction));

append(rlpTxRaw, Ethereum::RLP::encode(Identifiers::rlpMessageVersion));

append(rlpTxRaw, Ethereum::RLP::encodeList(signaturesList));

append(rlpTxRaw, Ethereum::RLP::encode(txRaw));

return Ethereum::RLP::encodeList(rlpTxRaw);

}

Data Signer::buildMessageToSign(Data &txRaw) {

auto data = Data();

Data bytes(Identifiers::networkId.begin(), Identifiers::networkId.end());

append(data, bytes);

append(data, txRaw);

return data;

}

Proto::SigningOutput Signer::createProtoOutput(std::string &signature, const std::string &signedTx) {

auto output = Proto::SigningOutput();

output.set_signature(signature);

output.set_encoded(signedTx);

return output;

}

std::string Signer::encodeBase64WithChecksum(const std::string &prefix, const TW::Data &rawTx) {

auto checksum = Hash::sha256(Hash::sha256(rawTx));

std::vector<unsigned char> checksumPart(checksum.begin(), checksum.begin() + checkSumSize);

auto data = Data();

append(data, rawTx);

append(data, checksumPart);

return prefix + TW::Base64::encode(data);

}