// Copyright (c) The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_KERNEL_SIGNET_H

#define BITCOIN_KERNEL_SIGNET_H

#include <hash.h>

#include <kernel/messagestartchars.h>

#include <uint256.h>

#include <util/strencodings.h>

#include <algorithm>

#include <cstdint>

#include <vector>

namespace kernel {

using namespace util::hex_literals;

inline const std::vector<uint8_t> SIGNET_DEFAULT_CHALLENGE{

    "512103ad5e0edad18cb1f0fc0d28a3d4f1f3e445640337489abb10404f2d1e086be430210359ef5021964fe22d6f8e05b2463c9540ce96883fe3b278760f048f5189f2e6c452ae"_hex_v_u8};

/**

 * Return the message start bytes for a signet: the first four bytes of the

 * double-SHA256 hash of the serialized signet challenge script (BIP325)

 */

inline MessageStartChars GetSignetMessageStart(const std::vector<uint8_t>& signet_challenge)

{

    HashWriter h{};

    h << signet_challenge;

    const uint256 hash = h.GetHash();

    MessageStartChars msg_start;

    std::copy_n(hash.begin(), 4, msg_start.begin());

    return msg_start;

}

} // namespace kernel

#endif // BITCOIN_KERNEL_SIGNET_H