// 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 "Address.h"

#include "../Base32.h"

#include "../HexCoding.h"

#include "Crc.h"

#include <TrezorCrypto/memzero.h>

#include <TrustWalletCore/TWStellarVersionByte.h>

#include <array>

#include <cassert>

using namespace TW::Stellar;

bool Address::isValid(const std::string& string) {

bool valid = false;

if (string.length() != size) {

return false;

}

// Check that it decodes correctly

Data decoded;

valid = Base32::decode(string, decoded);

// ... and that version byte is 0x30

if (valid && TWStellarVersionByte(decoded[0]) != TWStellarVersionByte::TWStellarVersionByteAccountID) {

valid = false;

}

// ... and that checksums match

uint16_t checksum_expected = Crc::crc16(decoded.data(), 33);

uint16_t checksum_actual = static_cast<uint16_t>((decoded[34] << 8) | decoded[33]); // unsigned short (little endian)

if (valid && checksum_expected != checksum_actual) {

valid = false;

}

memzero(decoded.data(), decoded.size());

return valid;

}

Address::Address(const std::string& string) {

// Ensure address is valid

if (!isValid(string)) {

throw std::invalid_argument("Invalid address data");

}

Data decoded;

Base32::decode(string, decoded);

std::copy(decoded.begin() + 1, decoded.begin() + 1 + bytes.size(), bytes.begin());

memzero(decoded.data(), decoded.size());

}

Address::Address(const PublicKey& publicKey) {

if (publicKey.type != TWPublicKeyTypeED25519) {

throw std::invalid_argument("Invalid public key type");

}

static_assert(PublicKey::ed25519Size == keySize);

std::copy(publicKey.bytes.begin(), publicKey.bytes.end(), bytes.data());

}

std::string Address::string() const {

// version + key bytes + checksum

constexpr uint8_t keylen = 1 + 32 + 2;

std::array<uint8_t, keylen> bytes_full;

bytes_full[0] = 6 << 3; // 'G'

std::copy(bytes.begin(), bytes.end(), bytes_full.begin() + 1);

// Last two bytes are the checksum

uint16_t checksum = Crc::crc16(bytes_full.data(), 33);

bytes_full[keylen - 2] = checksum & 0x00ff;

bytes_full[keylen - 1] = (checksum >> 8) & 0x00ff;

Data bytesAsData;

bytesAsData.assign(bytes_full.begin(), bytes_full.end());

auto out = Base32::encode(bytesAsData);

return out;

}