// -*- 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
// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCUDACXX___FUNCTIONAL_NOT_FN_H
#define _LIBCUDACXX___FUNCTIONAL_NOT_FN_H

#include <cuda/std/detail/__config>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <cuda/std/__functional/invoke.h>
#include <cuda/std/__functional/perfect_forward.h>
#include <cuda/std/__type_traits/decay.h>
#include <cuda/std/__type_traits/enable_if.h>
#include <cuda/std/__type_traits/is_constructible.h>
#include <cuda/std/__type_traits/is_move_constructible.h>
#include <cuda/std/__utility/forward.h>

_LIBCUDACXX_BEGIN_NAMESPACE_STD

#if _CCCL_STD_VER > 2014

struct __not_fn_op
{
  template <class... _Args>
  _LIBCUDACXX_HIDE_FROM_ABI _CCCL_CONSTEXPR_CXX20 auto operator()(_Args&&... __args) const
    noexcept(noexcept(!_CUDA_VSTD::invoke(_CUDA_VSTD::forward<_Args>(__args)...)))
      -> decltype(!_CUDA_VSTD::invoke(_CUDA_VSTD::forward<_Args>(__args)...))
  {
    return !_CUDA_VSTD::invoke(_CUDA_VSTD::forward<_Args>(__args)...);
  }
};

template <class _Fn>
struct __not_fn_t : __perfect_forward<__not_fn_op, _Fn>
{
  using __base = __perfect_forward<__not_fn_op, _Fn>;
#  if defined(_CCCL_COMPILER_NVRTC) // nvbug 3961621
  _CCCL_HIDE_FROM_ABI constexpr __not_fn_t() noexcept = default;

  _LIBCUDACXX_TEMPLATE(class _OrigFn)
  _LIBCUDACXX_REQUIRES(_CCCL_TRAIT(is_same, _Fn, __decay_t<_OrigFn>))
  _LIBCUDACXX_HIDE_FROM_ABI constexpr __not_fn_t(_OrigFn&& __fn) noexcept(
    noexcept(__base(_CUDA_VSTD::declval<_OrigFn>())))
      : __base(_CUDA_VSTD::forward<_OrigFn>(__fn))
  {}
#  else
  using __base::__base;
#  endif
};

template <class _Fn, class = enable_if_t<is_constructible_v<decay_t<_Fn>, _Fn> && is_move_constructible_v<decay_t<_Fn>>>>
_LIBCUDACXX_HIDE_FROM_ABI _CCCL_CONSTEXPR_CXX20 auto not_fn(_Fn&& __f)
{
  return __not_fn_t<decay_t<_Fn>>(_CUDA_VSTD::forward<_Fn>(__f));
}

#endif // _CCCL_STD_VER > 2014

_LIBCUDACXX_END_NAMESPACE_STD

#endif // _LIBCUDACXX___FUNCTIONAL_NOT_FN_H
