// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Limenka developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <consensus/amount.h>
#include <policy/feerate.h>
#include <tinyformat.h>

#include <cmath>

CFeeRate::CFeeRate(const CAmount& nFeePaid, uint32_t num_bytes)
{
    const int64_t nSize{num_bytes};

    if (nSize > 0) {
        nSatoshisPerK = nFeePaid * 1000 / nSize;
    } else {
        nSatoshisPerK = 0;
    }
}

CAmount CFeeRate::GetFee(uint32_t num_bytes) const
{
    const int64_t nSize{num_bytes};

    // Be explicit that we're converting from a double to int64_t (CAmount) here.
    // Integer ceil division - exact for the 128-bit product (no double
    // precision loss above 2^53).  For non-positive products, truncation
    // toward zero IS ceil; for positive products, round up.
    const CAmount product{nSatoshisPerK * nSize};
    CAmount nFee{product > 0 ? (product + 999) / 1000 : product / 1000};

    if (nFee == 0 && nSize != 0) {
        if (nSatoshisPerK > 0) nFee = CAmount(1);
        if (nSatoshisPerK < 0) nFee = CAmount(-1);
    }

    return nFee;
}

std::string CFeeRate::ToString(const FeeEstimateMode& fee_estimate_mode) const
{
    switch (fee_estimate_mode) {
    case FeeEstimateMode::SAT_VB: return strprintf("%d.%03d %s/vB", static_cast<int64_t>(nSatoshisPerK / 1000), static_cast<int64_t>(nSatoshisPerK % 1000), CURRENCY_ATOM);
    default:                      return strprintf("%d.%08d %s/kvB", static_cast<int64_t>(nSatoshisPerK / COIN), static_cast<int64_t>(nSatoshisPerK % COIN), CURRENCY_UNIT);
    }
}

std::string CFeeRate::SatsToString() const {
    return strprintf("%d.%03d", static_cast<int64_t>(nSatoshisPerK / 1000), static_cast<int64_t>(nSatoshisPerK % 1000));
}