//===----------------------------------------------------------------------===//
//
// Part of CUDA Experimental in CUDA C++ Core Libraries,
// 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) 2026 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

#ifndef COMMON_GROUP_CUH
#define COMMON_GROUP_CUH

#include <cuda/barrier>
#include <cuda/std/cstddef>
#include <cuda/std/type_traits>
#include <cuda/warp>

#include <cuda/experimental/group.cuh>

#include "testing.cuh"

namespace
{
template <class T, cuda::std::size_t Id>
__device__ T global_barriers_storage;

//! @brief Returns reference to an array of N cuda::barrier objects with suitable thread scope for level allocated in
//!        suitable address space (shared or device memory). Id parameter can be used to create unique object.
template <cuda::std::size_t N, cuda::std::size_t Id = 0, class Level>
__device__ auto& get_barriers(const Level& level) noexcept
{
  constexpr auto scope = cudax::__minimum_required_scope_for<Level>();

  using Barrier         = cuda::barrier<scope>;
  using BarriersStorage = cuda::std::aligned_storage_t<N * sizeof(Barrier), alignof(Barrier)>;

  if constexpr (scope >= cuda::thread_scope_block)
  {
    __shared__ BarriersStorage shared_barriers_storage;
    return reinterpret_cast<Barrier(&)[N]>(shared_barriers_storage);
  }
  else
  {
    return reinterpret_cast<Barrier(&)[N]>(global_barriers_storage<BarriersStorage, Id>);
  }
}

struct ThreadsInWarpMappingResult
{
  __device__ static constexpr ::cuda::std::size_t static_group_count()
  {
    return 1;
  }

  __device__ unsigned group_count() const
  {
    return 1;
  }

  __device__ unsigned group_rank() const
  {
    return 0;
  }

  __device__ static constexpr ::cuda::std::size_t static_unit_count()
  {
    return 32;
  }

  __device__ unsigned unit_count() const
  {
    return 32;
  }

  __device__ unsigned unit_rank() const
  {
    return cuda::gpu_thread.rank_as<unsigned>(cuda::warp);
  }

  __device__ cuda::device::lane_mask lane_mask() const noexcept
  {
    return cuda::device::lane_mask::all();
  }

  __device__ bool is_valid() const
  {
    return true;
  }

  __device__ static constexpr bool is_always_exhaustive() noexcept
  {
    return true;
  }

  __device__ static constexpr bool is_always_contiguous() noexcept
  {
    return true;
  }
};
} // namespace

#endif // COMMON_GROUP_CUH