// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___CHRONO_YEAR_MONTH_H
#define _LIBCPP___CHRONO_YEAR_MONTH_H

#include <__chrono/duration.h>
#include <__chrono/month.h>
#include <__chrono/year.h>
#include <__config>
#include <compare>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

#if _LIBCPP_STD_VER > 17

_LIBCPP_BEGIN_NAMESPACE_STD

namespace chrono
{

class year_month {
    chrono::year  __y;
    chrono::month __m;
public:
    _LIBCPP_HIDE_FROM_ABI year_month() = default;
    _LIBCPP_HIDE_FROM_ABI constexpr year_month(const chrono::year& __yval, const chrono::month& __mval) noexcept
        : __y{__yval}, __m{__mval} {}
    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::year  year()  const noexcept { return __y; }
    _LIBCPP_HIDE_FROM_ABI inline constexpr chrono::month month() const noexcept { return __m; }
    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator+=(const months& __dm) noexcept { this->__m += __dm; return *this; }
    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator-=(const months& __dm) noexcept { this->__m -= __dm; return *this; }
    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator+=(const years& __dy)  noexcept { this->__y += __dy; return *this; }
    _LIBCPP_HIDE_FROM_ABI inline constexpr year_month& operator-=(const years& __dy)  noexcept { this->__y -= __dy; return *this; }
    _LIBCPP_HIDE_FROM_ABI inline constexpr bool ok() const noexcept { return __y.ok() && __m.ok(); }
};

_LIBCPP_HIDE_FROM_ABI inline constexpr
year_month operator/(const year& __y, const month& __m) noexcept { return year_month{__y, __m}; }

_LIBCPP_HIDE_FROM_ABI inline constexpr
year_month operator/(const year& __y, int __m) noexcept { return year_month{__y, month(__m)}; }

_LIBCPP_HIDE_FROM_ABI inline constexpr
bool operator==(const year_month& __lhs, const year_month& __rhs) noexcept
{ return __lhs.year() == __rhs.year() && __lhs.month() == __rhs.month(); }

_LIBCPP_HIDE_FROM_ABI constexpr strong_ordering operator<=>(const year_month& __lhs, const year_month& __rhs) noexcept {
    if (auto __c = __lhs.year() <=> __rhs.year(); __c != 0)
      return __c;
    return __lhs.month() <=> __rhs.month();
}

_LIBCPP_HIDE_FROM_ABI constexpr
year_month operator+(const year_month& __lhs, const months& __rhs) noexcept
{
    int __dmi = static_cast<int>(static_cast<unsigned>(__lhs.month())) - 1 + __rhs.count();
    const int __dy = (__dmi >= 0 ? __dmi : __dmi-11) / 12;
    __dmi = __dmi - __dy * 12 + 1;
    return (__lhs.year() + years(__dy)) / month(static_cast<unsigned>(__dmi));
}

_LIBCPP_HIDE_FROM_ABI constexpr
year_month operator+(const months& __lhs, const year_month& __rhs) noexcept
{ return __rhs + __lhs; }

_LIBCPP_HIDE_FROM_ABI constexpr
year_month operator+(const year_month& __lhs, const years& __rhs) noexcept
{ return (__lhs.year() + __rhs) / __lhs.month(); }

_LIBCPP_HIDE_FROM_ABI constexpr
year_month operator+(const years& __lhs, const year_month& __rhs) noexcept
{ return __rhs + __lhs; }

_LIBCPP_HIDE_FROM_ABI constexpr
months operator-(const year_month& __lhs, const year_month& __rhs) noexcept
{ return (__lhs.year() - __rhs.year()) + months(static_cast<unsigned>(__lhs.month()) - static_cast<unsigned>(__rhs.month())); }

_LIBCPP_HIDE_FROM_ABI constexpr
year_month operator-(const year_month& __lhs, const months& __rhs) noexcept
{ return __lhs + -__rhs; }

_LIBCPP_HIDE_FROM_ABI constexpr
year_month operator-(const year_month& __lhs, const years& __rhs) noexcept
{ return __lhs + -__rhs; }

} // namespace chrono

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER > 17

#endif // _LIBCPP___CHRONO_YEAR_MONTH_H