#pragma once

#include <algorithm>
#include <cassert>
#include <cstddef>

namespace xrpl {

/** Calculate one number divided by another number in percentage.
 * The result is rounded up to the next integer, and capped in the range [0,100]
 * E.g. calculatePercent(1, 100) = 1 because 1/100 = 0.010000
 *      calculatePercent(1, 99) = 2 because 1/99 = 0.010101
 *      calculatePercent(0, 100) = 0
 *      calculatePercent(100, 100) = 100
 *      calculatePercent(200, 100) = 100 because the result is capped to 100
 *
 * @param count  dividend
 * @param total  divisor
 * @return the percentage, in [0, 100]
 *
 * @note total cannot be zero.
 * */
constexpr std::size_t
calculatePercent(std::size_t count, std::size_t total)
{
    assert(total != 0);  // NOTE No XRPL_ASSERT here, because constexpr
    return ((std::min(count, total) * 100) + total - 1) / total;
}

// unit tests
static_assert(calculatePercent(1, 2) == 50);
static_assert(calculatePercent(0, 100) == 0);
static_assert(calculatePercent(100, 100) == 100);
static_assert(calculatePercent(200, 100) == 100);
static_assert(calculatePercent(1, 100) == 1);
static_assert(calculatePercent(1, 99) == 2);
static_assert(calculatePercent(6, 14) == 43);
static_assert(calculatePercent(29, 33) == 88);
static_assert(calculatePercent(1, 64) == 2);
static_assert(calculatePercent(0, 100'000'000) == 0);
static_assert(calculatePercent(1, 100'000'000) == 1);
static_assert(calculatePercent(50'000'000, 100'000'000) == 50);
static_assert(calculatePercent(50'000'001, 100'000'000) == 51);
static_assert(calculatePercent(99'999'999, 100'000'000) == 100);

}  // namespace xrpl
