#pragma once

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <stdexcept>

namespace mp
{

struct Addition
{
    template <class TR, class TLhs, class TRhs> static void Op(TR& r, const TLhs& lhs, const TRhs& rhs)
    {
        static_assert(std::is_same_v<typename TR::ElementType, typename TLhs::ElementType>);
        static_assert(std::is_same_v<typename TR::ElementType, typename TRhs::ElementType>);
    
        using ElementType = TR::ElementType;
    
        ElementType carry = 0;
        size_t end = std::max(lhs.GetNumElements(), rhs.GetNumElements());
        for (size_t i = 0; i < end; ++i)
        {
            ElementType a = lhs.GetElement(i);
            ElementType b = rhs.GetElement(i);
    
            ElementType c = carry + a;
            carry = (c < a) ? 1 : 0;
            c += b;
            carry |= (c < b) ? 1 : 0;
    
            r.SetElement(i, c);
    
            // carry = (((a + carry) > (ELEMENT_MAX - b)) || (a > (ELEMENT_MAX - carry))) ? 1 : 0;
        }
    
        r.SetElement(end, carry);
    }
};

struct Subtraction
{
    template <class TR, class TLhs, class TRhs> static void Op(TR& r, const TLhs& lhs, const TRhs& rhs)
    {
        static_assert(std::is_same_v<typename TR::ElementType, typename TLhs::ElementType>);
        static_assert(std::is_same_v<typename TR::ElementType, typename TRhs::ElementType>);
    
        using ElementType = TR::ElementType;
    
        ElementType borrow = 0;
        size_t end = std::max(lhs.GetNumElements(), rhs.GetNumElements());
        for (size_t i = 0; i < end; ++i)
        {
            ElementType a = lhs.GetElement(i);
            ElementType b = rhs.GetElement(i);
    
            ElementType c = a - b - borrow;
    
            borrow = (a < b || (a - b) < borrow) ? 1 : 0;
    
            r.SetElement(i, c);
        }
    
        if (borrow > 0)
        {
            throw std::runtime_error("Subtraction result negative");
        }
    
        // r.SetElement(end, borrow);
    }
};

} // namespace mp