#ifndef AOCPP_DIVMOD_HPP_
#define AOCPP_DIVMOD_HPP_

#include <tuple>

#include "../doctest.h"

namespace aocpp {

template <typename T>
auto DivMod(T dividend, T divisor) -> std::pair<T, T>
{
  auto const quotient  = dividend / divisor;
  auto const remainder = dividend % divisor;
  if (remainder == 0 || (remainder > 0) == (divisor > 0)) {
    return {quotient, remainder};
  } else {
    return {quotient - 1, remainder + divisor};
  }
}

template <typename T>
auto Mod(T dividend, T divisor) -> T
{
  return DivMod(dividend, divisor).second;
}

template <typename T>
auto Div(T dividend, T divisor) -> T
{
  return DivMod(dividend, divisor).first;
}

TEST_SUITE("divmod.hpp") {
  TEST_CASE("DivMod behavior") {
    CHECK(DivMod<int>(2,5) == std::make_pair(0,2));
    CHECK(DivMod<int>(-2,5) == std::make_pair(-1,3));
    CHECK(DivMod<int>(2,-5) == std::make_pair(-1,-3));
    CHECK(DivMod<int>(-2,-5) == std::make_pair(0,-2));
    
    CHECK(DivMod<int>(-5,-5) == std::make_pair(1,0));
    CHECK(DivMod<int>(-5,5) == std::make_pair(-1,0));
    CHECK(DivMod<int>(5,-5) == std::make_pair(-1,0));
    CHECK(DivMod<int>(-5,-5) == std::make_pair(1,0));
  }
}

}

#endif