// Copyright (c) 2014-2019, The Monero Project
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// All rights reserved.
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// permitted provided that the following conditions are met:
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// 1. Redistributions of source code must retain the above copyright notice, this list of
//    conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
//    of conditions and the following disclaimer in the documentation and/or other
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
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//    prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers

#pragma once

#include <cstdint>
#include <cstddef>
#include <vector>
#include "cryptonote_config.h"
#include "common/util.h"

namespace crypto { struct hash; }

namespace cryptonote
{
    typedef std::uint64_t difficulty_type;

    /**
     * @brief checks if a hash fits the given difficulty
     *
     * The hash passes if (hash * difficulty) < 2^256.
     * Phrased differently, if (hash * difficulty) fits without overflow into
     * the least significant 256 bits of the 320 bit multiplication result.
     *
     * @param hash the hash to check
     * @param difficulty the difficulty to check against
     *
     * @return true if valid, else false
     */
    bool check_hash(const crypto::hash &hash, difficulty_type difficulty);

    // Add one timestamp and difficulty to the input arrays, trimming down the
    // array if necessary for usage in next_difficulty_v2.
    void add_timestamp_and_difficulty(cryptonote::network_type nettype,
                                      uint64_t chain_height,
                                      std::vector<uint64_t> &timestamps,
                                      std::vector<difficulty_type> &difficulties,
                                      uint64_t timestamp,
                                      uint64_t cumulative_difficulty);


    constexpr difficulty_type PULSE_FIXED_DIFFICULTY = 1'000'000;
    enum struct difficulty_calc_mode
    {
      use_old_lwma,
      hf12_override,
      hf16_override,
      normal,
    };

    difficulty_calc_mode difficulty_mode(network_type nettype, uint8_t hf_version, uint64_t height);

    difficulty_type next_difficulty_v2(std::vector<std::uint64_t> timestamps,
                                       std::vector<difficulty_type> cumulative_difficulties,
                                       size_t target_second,
                                       difficulty_calc_mode mode);
}
