/******************************************************************************
 * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
 * Modifications Copyright (c) 2019-2025, Advanced Micro Devices, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the NVIDIA CORPORATION nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ******************************************************************************/
#pragma once

#include <thrust/detail/config.h>

#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

#if THRUST_DEVICE_COMPILER == THRUST_DEVICE_COMPILER_HIP

#  include <thrust/system/hip/config.h>

#  include <thrust/detail/alignment.h>
#  include <thrust/detail/minmax.h>
#  include <thrust/detail/raw_reference_cast.h>
#  include <thrust/detail/temporary_array.h>
#  include <thrust/detail/type_traits/iterator/is_output_iterator.h>
#  include <thrust/device_vector.h>
#  include <thrust/distance.h>
#  include <thrust/functional.h>
#  include <thrust/pair.h>
#  include <thrust/system/hip/detail/general/temp_storage.h>
#  include <thrust/system/hip/detail/get_value.h>
#  include <thrust/system/hip/detail/par_to_seq.h>
#  include <thrust/system/hip/detail/util.h>

#  include <cstdint>

// rocprim include
#  include <rocprim/rocprim.hpp>

THRUST_NAMESPACE_BEGIN

template <typename DerivedPolicy,
          typename InputIterator1,
          typename InputIterator2,
          typename OutputIterator1,
          typename OutputIterator2,
          typename BinaryPredicate>
THRUST_HOST_DEVICE thrust::pair<OutputIterator1, OutputIterator2> reduce_by_key(
  const thrust::detail::execution_policy_base<DerivedPolicy>& exec,
  InputIterator1 keys_first,
  InputIterator1 keys_last,
  InputIterator2 values_first,
  OutputIterator1 keys_output,
  OutputIterator2 values_output,
  BinaryPredicate binary_pred);

namespace hip_rocprim
{

namespace __reduce_by_key
{

template <typename Derived,
          typename KeysInputIt,
          typename ValuesInputIt,
          typename UniqueOutputIt,
          typename AggregatesOutputIt,
          typename UniqueCountOutputIt,
          typename BinaryFunction,
          typename KeyCompareFunction>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_reduce_by_key(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  KeysInputIt keys_input,
  ValuesInputIt values_input,
  const size_t size,
  UniqueOutputIt unique_output,
  AggregatesOutputIt aggregates_output,
  UniqueCountOutputIt unique_count_output,
  BinaryFunction reduce_op,
  KeyCompareFunction key_compare_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<decltype(nondeterministic(policy))::value, hipError_t>
{
  return rocprim::reduce_by_key(
    temporary_storage,
    storage_size,
    keys_input,
    values_input,
    size,
    unique_output,
    aggregates_output,
    unique_count_output,
    reduce_op,
    key_compare_op,
    stream,
    debug_sync);
}

template <typename Derived,
          typename KeysInputIt,
          typename ValuesInputIt,
          typename UniqueOutputIt,
          typename AggregatesOutputIt,
          typename UniqueCountOutputIt,
          typename BinaryFunction,
          typename KeyCompareFunction>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_reduce_by_key(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  KeysInputIt keys_input,
  ValuesInputIt values_input,
  const size_t size,
  UniqueOutputIt unique_output,
  AggregatesOutputIt aggregates_output,
  UniqueCountOutputIt unique_count_output,
  BinaryFunction reduce_op,
  KeyCompareFunction key_compare_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<!decltype(nondeterministic(policy))::value, hipError_t>
{
  return rocprim::deterministic_reduce_by_key(
    temporary_storage,
    storage_size,
    keys_input,
    values_input,
    size,
    unique_output,
    aggregates_output,
    unique_count_output,
    reduce_op,
    key_compare_op,
    stream,
    debug_sync);
}

template <typename Derived,
          typename KeysInputIt,
          typename ValuesInputIt,
          typename KeysOutputIt,
          typename ValuesOutputIt,
          typename EqualityOp,
          typename ReductionOp>
THRUST_RUNTIME_FUNCTION pair<KeysOutputIt, ValuesOutputIt> reduce_by_key(
  execution_policy<Derived>& policy,
  KeysInputIt keys_first,
  KeysInputIt keys_last,
  ValuesInputIt values_first,
  KeysOutputIt keys_output,
  ValuesOutputIt values_output,
  EqualityOp equality_op,
  ReductionOp reduction_op)
{
  using namespace thrust::system::hip_rocprim::temp_storage;

  using size_type = typename iterator_traits<KeysInputIt>::difference_type;

  size_type num_items       = thrust::distance(keys_first, keys_last);
  size_t temp_storage_bytes = 0;
  hipStream_t stream        = hip_rocprim::stream(policy);
  bool debug_sync           = THRUST_HIP_DEBUG_SYNC_FLAG;

  if (num_items == 0)
  {
    return thrust::make_pair(keys_output, values_output);
  }

  hip_rocprim::throw_on_error(
    invoke_reduce_by_key(
      policy,
      nullptr,
      temp_storage_bytes,
      keys_first,
      values_first,
      num_items,
      keys_output,
      values_output,
      static_cast<size_type*>(nullptr),
      reduction_op,
      equality_op,
      stream,
      debug_sync),
    "reduce_by_key failed on 1st step");

  size_t storage_size;
  void* ptr       = nullptr;
  void* temp_stor = nullptr;
  size_type* d_num_runs_out;

  auto l_part =
    make_linear_partition(make_partition(&temp_stor, temp_storage_bytes), ptr_aligned_array(&d_num_runs_out, 1));

  // Calculate storage_size including alignment
  hip_rocprim::throw_on_error(partition(ptr, storage_size, l_part));

  // Allocate temporary storage.
  thrust::detail::temporary_array<std::uint8_t, Derived> tmp(policy, storage_size);
  ptr = static_cast<void*>(tmp.data().get());

  // Create pointers with alignment
  hip_rocprim::throw_on_error(partition(ptr, storage_size, l_part));

  hip_rocprim::throw_on_error(
    invoke_reduce_by_key(
      policy,
      ptr,
      temp_storage_bytes,
      keys_first,
      values_first,
      num_items,
      keys_output,
      values_output,
      d_num_runs_out,
      reduction_op,
      equality_op,
      stream,
      debug_sync),
    "reduce_by_key failed on 2nd step");

  const auto num_runs_out = hip_rocprim::get_value(policy, d_num_runs_out);

  return thrust::make_pair(keys_output + num_runs_out, values_output + num_runs_out);
}

} // namespace __reduce_by_key

//-------------------------
// Thrust API entry points
//-------------------------

THRUST_EXEC_CHECK_DISABLE
template <class Derived,
          class KeyInputIt,
          class ValInputIt,
          class KeyOutputIt,
          class ValOutputIt,
          class BinaryPred,
          class BinaryOp>
pair<KeyOutputIt, ValOutputIt> THRUST_HOST_DEVICE reduce_by_key(
  execution_policy<Derived>& policy,
  KeyInputIt keys_first,
  KeyInputIt keys_last,
  ValInputIt values_first,
  KeyOutputIt keys_output,
  ValOutputIt values_output,
  BinaryPred binary_pred,
  BinaryOp binary_op)
{
  // struct workaround is required for HIP-clang
  struct workaround
  {
    THRUST_HOST static pair<KeyOutputIt, ValOutputIt>
    par(execution_policy<Derived>& policy,
        KeyInputIt keys_first,
        KeyInputIt keys_last,
        ValInputIt values_first,
        KeyOutputIt keys_output,
        ValOutputIt values_output,
        BinaryPred binary_pred,
        BinaryOp binary_op)
    {
      return __reduce_by_key::reduce_by_key(
        policy, keys_first, keys_last, values_first, keys_output, values_output, binary_pred, binary_op);
    }

#  if !__THRUST_HAS_HIPRT__
    THRUST_DEVICE static pair<KeyOutputIt, ValOutputIt>
    seq(execution_policy<Derived>& policy,
        KeyInputIt keys_first,
        KeyInputIt keys_last,
        ValInputIt values_first,
        KeyOutputIt keys_output,
        ValOutputIt values_output,
        BinaryPred binary_pred,
        BinaryOp binary_op)
    {
      return thrust::reduce_by_key(
        cvt_to_seq(derived_cast(policy)),
        keys_first,
        keys_last,
        values_first,
        keys_output,
        values_output,
        binary_pred,
        binary_op);
    }
#  endif
  };
#  if __THRUST_HAS_HIPRT__
  return workaround::par(
    policy, keys_first, keys_last, values_first, keys_output, values_output, binary_pred, binary_op);
#  else
  return workaround::seq(
    policy, keys_first, keys_last, values_first, keys_output, values_output, binary_pred, binary_op);
#  endif
}

template <class Derived, class KeyInputIt, class ValInputIt, class KeyOutputIt, class ValOutputIt, class BinaryPred>
pair<KeyOutputIt, ValOutputIt> THRUST_HOST_DEVICE reduce_by_key(
  execution_policy<Derived>& policy,
  KeyInputIt keys_first,
  KeyInputIt keys_last,
  ValInputIt values_first,
  KeyOutputIt keys_output,
  ValOutputIt values_output,
  BinaryPred binary_pred)
{
  using value_type = typename thrust::detail::eval_if<thrust::detail::is_output_iterator<ValOutputIt>::value,
                                                      thrust::iterator_value<ValInputIt>,
                                                      thrust::iterator_value<ValOutputIt>>::type;
  return hip_rocprim::reduce_by_key(
    policy, keys_first, keys_last, values_first, keys_output, values_output, binary_pred, plus<value_type>());
}

template <class Derived, class KeyInputIt, class ValInputIt, class KeyOutputIt, class ValOutputIt>
pair<KeyOutputIt, ValOutputIt> THRUST_HOST_DEVICE reduce_by_key(
  execution_policy<Derived>& policy,
  KeyInputIt keys_first,
  KeyInputIt keys_last,
  ValInputIt values_first,
  KeyOutputIt keys_output,
  ValOutputIt values_output)
{
  using KeyT = typename thrust::iterator_value<KeyInputIt>::type;
  return hip_rocprim::reduce_by_key(
    policy, keys_first, keys_last, values_first, keys_output, values_output, equal_to<KeyT>());
}

} // namespace hip_rocprim

THRUST_NAMESPACE_END

#  include <thrust/memory.h>
#  include <thrust/reduce.h>

#endif
