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 *
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 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
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 *       derived from this software without specific prior written permission.
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#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/integer_math.h>
#  include <thrust/detail/temporary_array.h>
#  include <thrust/detail/type_traits.h>
#  include <thrust/distance.h>
#  include <thrust/iterator/iterator_traits.h>
#  include <thrust/system/hip/detail/dispatch.h>

#  include <cstdint>

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

THRUST_NAMESPACE_BEGIN
namespace hip_rocprim
{
namespace __scan
{

template <typename Derived, typename InputIt, typename OutputIt, typename Size, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_inclusive_scan(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  InputIt input,
  OutputIt output,
  const Size num_items,
  ScanOp scan_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<decltype(nondeterministic(policy))::value, hipError_t>
{
  using acc_type = typename ::std::iterator_traits<InputIt>::value_type;
  return ::rocprim::inclusive_scan<::rocprim::default_config, InputIt, OutputIt, ScanOp, acc_type>(
    temporary_storage, storage_size, input, output, num_items, scan_op, stream, debug_sync);
}

template <typename Derived, typename InputIt, typename OutputIt, typename Size, typename InitValueT, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_inclusive_scan(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  InputIt input,
  OutputIt output,
  const Size num_items,
  InitValueT init,
  ScanOp scan_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<decltype(nondeterministic(policy))::value, hipError_t>
{
  using acc_type = typename ::std::iterator_traits<InputIt>::value_type;
  return ::rocprim::inclusive_scan<::rocprim::default_config, InputIt, OutputIt, InitValueT, ScanOp, acc_type>(
    temporary_storage, storage_size, input, output, init, num_items, scan_op, stream, debug_sync);
}

template <typename Derived, typename InputIt, typename OutputIt, typename Size, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_inclusive_scan(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  InputIt input,
  OutputIt output,
  const Size num_items,
  ScanOp scan_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<!decltype(nondeterministic(policy))::value, hipError_t>
{
  using acc_type = typename ::std::iterator_traits<InputIt>::value_type;
  return ::rocprim::deterministic_inclusive_scan<::rocprim::default_config, InputIt, OutputIt, ScanOp, acc_type>(
    temporary_storage, storage_size, input, output, num_items, scan_op, stream, debug_sync);
}

template <typename Derived, typename InputIt, typename OutputIt, typename Size, typename InitValueT, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_inclusive_scan(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  InputIt input,
  OutputIt output,
  const Size num_items,
  InitValueT init,
  ScanOp scan_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<!decltype(nondeterministic(policy))::value, hipError_t>
{
  using acc_type = typename ::std::iterator_traits<InputIt>::value_type;
  return ::rocprim::
    deterministic_inclusive_scan<::rocprim::default_config, InputIt, OutputIt, InitValueT, ScanOp, acc_type>(
      temporary_storage, storage_size, input, output, init, num_items, scan_op, stream, debug_sync);
}

template <typename Derived, typename InputIt, typename OutputIt, typename Size, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION OutputIt
inclusive_scan(execution_policy<Derived>& policy, InputIt input_it, OutputIt output_it, Size num_items, ScanOp scan_op)
{
  if (num_items == 0)
  {
    return output_it;
  }

  size_t storage_size = 0;
  hipStream_t stream  = hip_rocprim::stream(policy);
  bool debug_sync     = THRUST_HIP_DEBUG_SYNC_FLAG;

  // Determine temporary device storage requirements.
  hip_rocprim::throw_on_error(
    invoke_inclusive_scan(policy, nullptr, storage_size, input_it, output_it, num_items, scan_op, stream, debug_sync),
    "scan failed on 1st step");

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

  // Run scan.
  hip_rocprim::throw_on_error(
    invoke_inclusive_scan(policy, ptr, storage_size, input_it, output_it, num_items, scan_op, stream, debug_sync),
    "scan failed on 2nd step");

  hip_rocprim::throw_on_error(hip_rocprim::synchronize_optional(policy), "inclusive_scan: failed to synchronize");

  return output_it + num_items;
}

template <typename Derived, typename InputIt, typename OutputIt, typename Size, typename InitValueT, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION OutputIt inclusive_scan(
  execution_policy<Derived>& policy,
  InputIt input_it,
  OutputIt output_it,
  Size num_items,
  InitValueT init,
  ScanOp scan_op)
{
  if (num_items == 0)
  {
    return output_it;
  }

  size_t storage_size = 0;
  hipStream_t stream  = hip_rocprim::stream(policy);
  bool debug_sync     = THRUST_HIP_DEBUG_SYNC_FLAG;

  // Determine temporary device storage requirements.
  hip_rocprim::throw_on_error(
    invoke_inclusive_scan(
      policy, nullptr, storage_size, input_it, output_it, num_items, init, scan_op, stream, debug_sync),
    "scan failed on 1st step");

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

  // Run scan.
  hip_rocprim::throw_on_error(
    invoke_inclusive_scan(policy, ptr, storage_size, input_it, output_it, num_items, init, scan_op, stream, debug_sync),
    "scan failed on 2nd step");

  hip_rocprim::throw_on_error(hip_rocprim::synchronize_optional(policy), "inclusive_scan: failed to synchronize");

  return output_it + num_items;
}

template <typename Derived, typename InputIt, typename OutputIt, typename T, typename Size, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_exclusive_scan(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  InputIt input,
  OutputIt output,
  T init,
  const Size num_items,
  ScanOp scan_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<decltype(nondeterministic(policy))::value, hipError_t>
{
  using acc_type = ::rocprim::detail::input_type_t<T>;
  return ::rocprim::exclusive_scan<::rocprim::default_config, InputIt, OutputIt, T, ScanOp, acc_type>(
    temporary_storage, storage_size, input, output, init, num_items, scan_op, stream, debug_sync);
}

template <typename Derived, typename InputIt, typename OutputIt, typename T, typename Size, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION auto invoke_exclusive_scan(
  execution_policy<Derived>& policy,
  void* temporary_storage,
  size_t& storage_size,
  InputIt input,
  OutputIt output,
  T init,
  const Size num_items,
  ScanOp scan_op,
  const hipStream_t stream,
  bool debug_sync) -> std::enable_if_t<!decltype(nondeterministic(policy))::value, hipError_t>
{
  using acc_type = ::rocprim::detail::input_type_t<T>;
  return ::rocprim::deterministic_exclusive_scan<::rocprim::default_config, InputIt, OutputIt, T, ScanOp, acc_type>(
    temporary_storage, storage_size, input, output, init, num_items, scan_op, stream, debug_sync);
}

template <typename Derived, typename InputIt, typename OutputIt, typename Size, typename T, typename ScanOp>
THRUST_HIP_RUNTIME_FUNCTION OutputIt exclusive_scan(
  execution_policy<Derived>& policy, InputIt input_it, OutputIt output_it, Size num_items, T init, ScanOp scan_op)
{
  if (num_items == 0)
  {
    return output_it;
  }

  size_t storage_size = 0;
  hipStream_t stream  = hip_rocprim::stream(policy);
  bool debug_sync     = THRUST_HIP_DEBUG_SYNC_FLAG;

  // Determine temporary device storage requirements.
  hip_rocprim::throw_on_error(
    invoke_exclusive_scan(
      policy, nullptr, storage_size, input_it, output_it, init, num_items, scan_op, stream, debug_sync),
    "scan failed on 1st step");

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

  // Run scan.
  hip_rocprim::throw_on_error(
    invoke_exclusive_scan(policy, ptr, storage_size, input_it, output_it, init, num_items, scan_op, stream, debug_sync),
    "scan failed on 2nd step");

  hip_rocprim::throw_on_error(hip_rocprim::synchronize_optional(policy), "exclusive_scan: failed to synchronize");

  return output_it + num_items;
}

} // namespace __scan

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

template <typename Derived, typename InputIt, typename Size, typename OutputIt, typename T, typename ScanOp>
THRUST_HOST_DEVICE OutputIt inclusive_scan_n(
  thrust::hip_rocprim::execution_policy<Derived>& policy,
  InputIt first,
  Size num_items,
  OutputIt result,
  T init,
  ScanOp scan_op)
{
  // struct workaround is required for HIP-clang
  struct workaround
  {
    THRUST_HOST static OutputIt
    par(execution_policy<Derived>& policy, InputIt first, Size num_items, OutputIt result, T init, ScanOp scan_op)
    {
      return result = __scan::inclusive_scan(policy, first, result, num_items, init, scan_op);
    }
#  if !__THRUST_HAS_HIPRT__
    THRUST_DEVICE static OutputIt
    seq(execution_policy<Derived>& policy, InputIt first, Size num_items, OutputIt result, T init, ScanOp scan_op)
    {
      return result = thrust::inclusive_scan(
               cvt_to_seq(derived_cast(policy)), first, first + num_items, result, init, scan_op);
    }
#  endif
  };
#  if __THRUST_HAS_HIPRT__
  return workaround::par(policy, first, num_items, result, init, scan_op);
#  else
  return workaround::seq(policy, first, num_items, result, init, scan_op);
#  endif
}

template <typename Derived, typename InputIt, typename Size, typename OutputIt, typename ScanOp>
THRUST_HOST_DEVICE OutputIt inclusive_scan_n(
  thrust::hip_rocprim::execution_policy<Derived>& policy, InputIt first, Size num_items, OutputIt result, ScanOp scan_op)
{
  // struct workaround is required for HIP-clang
  struct workaround
  {
    THRUST_HOST static OutputIt
    par(execution_policy<Derived>& policy, InputIt first, Size num_items, OutputIt result, ScanOp scan_op)
    {
      return result = __scan::inclusive_scan(policy, first, result, num_items, scan_op);
    }
#  if !__THRUST_HAS_HIPRT__
    THRUST_DEVICE static OutputIt
    seq(execution_policy<Derived>& policy, InputIt first, Size num_items, OutputIt result, ScanOp scan_op)
    {
      return result =
               thrust::inclusive_scan(cvt_to_seq(derived_cast(policy)), first, first + num_items, result, scan_op);
    }
#  endif
  };
#  if __THRUST_HAS_HIPRT__
  return workaround::par(policy, first, num_items, result, scan_op);
#  else
  return workaround::seq(policy, first, num_items, result, scan_op);
#  endif
}

template <typename Derived, typename InputIt, typename OutputIt, typename ScanOp>
THRUST_HOST_DEVICE OutputIt inclusive_scan(
  thrust::hip_rocprim::execution_policy<Derived>& policy, InputIt first, InputIt last, OutputIt result, ScanOp scan_op)
{
  using diff_t           = typename thrust::iterator_traits<InputIt>::difference_type;
  diff_t const num_items = thrust::distance(first, last);
  return thrust::hip_rocprim::inclusive_scan_n(policy, first, num_items, result, scan_op);
}

template <typename Derived, typename InputIt, typename OutputIt, typename T, typename ScanOp>
THRUST_HOST_DEVICE OutputIt inclusive_scan(
  thrust::hip_rocprim::execution_policy<Derived>& policy,
  InputIt first,
  InputIt last,
  OutputIt result,
  T init,
  ScanOp scan_op)
{
  using diff_t           = typename thrust::iterator_traits<InputIt>::difference_type;
  diff_t const num_items = thrust::distance(first, last);
  return thrust::hip_rocprim::inclusive_scan_n(policy, first, num_items, result, init, scan_op);
}

template <typename Derived, typename InputIt, typename OutputIt>
THRUST_HOST_DEVICE OutputIt
inclusive_scan(thrust::hip_rocprim::execution_policy<Derived>& policy, InputIt first, InputIt last, OutputIt result)
{
  return thrust::hip_rocprim::inclusive_scan(policy, first, last, result, thrust::plus<>{});
}

THRUST_EXEC_CHECK_DISABLE
template <typename Derived, typename InputIt, typename Size, typename OutputIt, typename T, typename ScanOp>
THRUST_HOST_DEVICE OutputIt exclusive_scan_n(
  thrust::hip_rocprim::execution_policy<Derived>& policy,
  InputIt first,
  Size num_items,
  OutputIt result,
  T init,
  ScanOp scan_op)
{
  // struct workaround is required for HIP-clang
  struct workaround
  {
    THRUST_HOST static OutputIt
    par(execution_policy<Derived>& policy, InputIt first, Size num_items, OutputIt result, T init, ScanOp scan_op)
    {
      return result = __scan::exclusive_scan(policy, first, result, num_items, init, scan_op);
    }
#  if !__THRUST_HAS_HIPRT__
    THRUST_DEVICE static OutputIt
    seq(execution_policy<Derived>& policy, InputIt first, Size num_items, OutputIt result, T init, ScanOp scan_op)
    {
      return result = thrust::exclusive_scan(
               cvt_to_seq(derived_cast(policy)), first, first + num_items, result, init, scan_op);
    }
#  endif
  };
#  if __THRUST_HAS_HIPRT__
  return workaround::par(policy, first, num_items, result, init, scan_op);
#  else
  return workaround::seq(policy, first, num_items, result, init, scan_op);
#  endif
}

template <typename Derived, typename InputIt, typename OutputIt, typename T, typename ScanOp>
THRUST_HOST_DEVICE OutputIt exclusive_scan(
  thrust::hip_rocprim::execution_policy<Derived>& policy,
  InputIt first,
  InputIt last,
  OutputIt result,
  T init,
  ScanOp scan_op)
{
  using diff_t           = typename thrust::iterator_traits<InputIt>::difference_type;
  diff_t const num_items = thrust::distance(first, last);
  return thrust::hip_rocprim::exclusive_scan_n(policy, first, num_items, result, init, scan_op);
}

template <typename Derived, typename InputIt, typename OutputIt, typename T>
THRUST_HOST_DEVICE OutputIt exclusive_scan(
  thrust::hip_rocprim::execution_policy<Derived>& policy, InputIt first, InputIt last, OutputIt result, T init)
{
  return thrust::hip_rocprim::exclusive_scan(policy, first, last, result, init, thrust::plus<>{});
}

template <typename Derived, typename InputIt, typename OutputIt>
THRUST_HOST_DEVICE OutputIt
exclusive_scan(thrust::hip_rocprim::execution_policy<Derived>& policy, InputIt first, InputIt last, OutputIt result)
{
  using init_type = typename thrust::iterator_traits<InputIt>::value_type;
  return hip_rocprim::exclusive_scan(policy, first, last, result, init_type{});
}

} // namespace hip_rocprim
THRUST_NAMESPACE_END

#  include <thrust/scan.h>

#endif // THRUST_DEVICE_COMPILER == THRUST_DEVICE_COMPILER_HIP