//===----------------------------------------------------------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//

// <cuda/std/optional>

// template <class T, class U> constexpr bool operator==(const optional<T>& x, const optional<U>& y);

#include <cuda/std/cassert>
#include <cuda/std/optional>
#include <cuda/std/type_traits>

#include "cuda/std/__type_traits/reference_constructs_from_temporary.h"
#include "test_macros.h"

using cuda::std::optional;

struct X
{
  int i_;

  __host__ __device__ constexpr X(int i)
      : i_(i)
  {}
};

__host__ __device__ constexpr bool operator==(const X& lhs, const X& rhs)
{
  return lhs.i_ == rhs.i_;
}

template <class T>
__host__ __device__ constexpr void test()
{
  {
    using O = optional<T>;
    cuda::std::remove_reference_t<T> one{1};
    cuda::std::remove_reference_t<T> two{2};

    O o1{}; // disengaged
    O o2{}; // disengaged
    O o3{one}; // engaged
    O o4{two}; // engaged
    O o5{one}; // engaged

    assert(o1 == o1);
    assert(o1 == o2);
    assert(!(o1 == o3));
    assert(!(o1 == o4));
    assert(!(o1 == o5));

    assert(o2 == o1);
    assert(o2 == o2);
    assert(!(o2 == o3));
    assert(!(o2 == o4));
    assert(!(o2 == o5));

    assert(!(o3 == o1));
    assert(!(o3 == o2));
    assert(o3 == o3);
    assert(!(o3 == o4));
    assert(o3 == o5);

    assert(!(o4 == o1));
    assert(!(o4 == o2));
    assert(!(o4 == o3));
    assert(o4 == o4);
    assert(!(o4 == o5));

    assert(!(o5 == o1));
    assert(!(o5 == o2));
    assert(o5 == o3);
    assert(!(o5 == o4));
    assert(o5 == o5);
  }
  {
    using O1 = optional<int>;
    using O2 = optional<long>;
    O1 o1(42);
    assert(o1 == O2(42));
    assert(!(O2(101) == o1));
  }
  {
    using O1 = optional<int>;
    using O2 = optional<const int>;
    O1 o1(42);
    assert(o1 == O2(42));
    assert(!(O2(101) == o1));
  }
}

__host__ __device__ constexpr bool test()
{
  test<int>();
#ifdef CCCL_ENABLE_OPTIONAL_REF
  test<int&>();
#endif // CCCL_ENABLE_OPTIONAL_REF

  return true;
}

int main(int, char**)
{
  test();
  static_assert(test());

  return 0;
}