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//
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// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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/*
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/*! \file thrust/system/hip/hipstdpar/impl/numeric.hpp
 *  \brief <tt>Numeric operations</tt> implementation detail header for HIPSTDPAR.
 */

#pragma once

#if defined(__HIPSTDPAR__)

#  include <thrust/adjacent_difference.h>
#  include <thrust/execution_policy.h>
#  include <thrust/inner_product.h>
#  include <thrust/reduce.h>
#  include <thrust/scan.h>
#  include <thrust/transform.h>
#  include <thrust/transform_reduce.h>
#  include <thrust/transform_scan.h>

#  include <algorithm>
#  include <execution>
#  include <type_traits>
#  include <utility>

#  include "hipstd.hpp"

namespace std
{
// BEGIN ADJACENT_DIFFERENCE
template <typename I, typename O, enable_if_t<::hipstd::is_offloadable_iterator<I, O>()>* = nullptr>
inline O adjacent_difference(execution::parallel_unsequenced_policy, I fi, I li, O fo)
{
  return ::thrust::adjacent_difference(::thrust::device, fi, li, fo);
}

template <typename I, typename O, enable_if_t<!::hipstd::is_offloadable_iterator<I, O>()>* = nullptr>
inline O adjacent_difference(execution::parallel_unsequenced_policy, I fi, I li, O fo)
{
  ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                          typename iterator_traits<O>::iterator_category>();

  return ::std::adjacent_difference(::std::execution::par, fi, li, fo);
}

template <typename I,
          typename O,
          typename Op,
          enable_if_t<::hipstd::is_offloadable_iterator<I, O>() && ::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O adjacent_difference(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op op)
{
  return ::thrust::adjacent_difference(::thrust::device, fi, li, fo, ::std::move(op));
}

template <typename I,
          typename O,
          typename Op,
          enable_if_t<!::hipstd::is_offloadable_iterator<I, O>() || !::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O adjacent_difference(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op op)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I, O>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                            typename iterator_traits<O>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op>())
  {
    ::hipstd::unsupported_callable_type<Op>();
  }

  return ::std::adjacent_difference(::std::execution::par, fi, li, fo, ::std::move(op));
}
// END ADJACENT_DIFFERENCE

// BEGIN REDUCE
template <typename I, enable_if_t<::hipstd::is_offloadable_iterator<I>()>* = nullptr>
inline typename iterator_traits<I>::value_type reduce(execution::parallel_unsequenced_policy, I f, I l)
{
  return ::thrust::reduce(::thrust::device, f, l);
}

template <typename I, enable_if_t<!::hipstd::is_offloadable_iterator<I>()>* = nullptr>
inline typename iterator_traits<I>::value_type reduce(execution::parallel_unsequenced_policy, I f, I l)
{
  ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category>();

  return ::std::reduce(::std::execution::par, f, l);
}

template <typename I, typename T, enable_if_t<::hipstd::is_offloadable_iterator<I>()>* = nullptr>
inline T reduce(execution::parallel_unsequenced_policy, I f, I l, T x)
{
  return ::thrust::reduce(::thrust::device, f, l, ::std::move(x));
}

template <typename I, typename T, enable_if_t<!::hipstd::is_offloadable_iterator<I>()>* = nullptr>
inline T reduce(execution::parallel_unsequenced_policy, I f, I l, T x)
{
  ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category>();

  return ::std::reduce(::std::execution::par, f, l, ::std::move(x));
}

template <typename I,
          typename T,
          typename Op,
          enable_if_t<::hipstd::is_offloadable_iterator<I>() && ::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline T reduce(execution::parallel_unsequenced_policy, I f, I l, T x, Op op)
{
  return ::thrust::reduce(::thrust::device, f, l, ::std::move(x), ::std::move(op));
}

template <typename I,
          typename T,
          typename Op,
          enable_if_t<!::hipstd::is_offloadable_iterator<I>() || !::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline T reduce(execution::parallel_unsequenced_policy, I f, I l, T x, Op op)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op>())
  {
    ::hipstd::unsupported_callable_type<Op>();
  }

  return ::std::reduce(::std::execution::par, f, l, ::std::move(x), ::std::move(op));
}
// END REDUCE

// BEGIN EXCLUSIVE_SCAN
template <typename I, typename O, typename T, enable_if_t<::hipstd::is_offloadable_iterator<I, O>()>* = nullptr>
inline O exclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, T x)
{
  return ::thrust::exclusive_scan(::thrust::device, fi, li, fo, ::std::move(x));
}

template <typename I, typename O, typename T, enable_if_t<!::hipstd::is_offloadable_iterator<I, O>()>* = nullptr>
inline O exclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, T x)
{
  ::hipstd::unsupported_iterator_category<typename std::iterator_traits<I>::iterator_category,
                                          typename std::iterator_traits<O>::iterator_category>();

  return ::std::exclusive_scan(::std::execution::par, fi, li, fo, ::std::move(x));
}

template <typename I,
          typename O,
          typename T,
          typename Op,
          enable_if_t<::hipstd::is_offloadable_iterator<I, O>() && ::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O exclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, T x, Op op)
{
  return ::thrust::exclusive_scan(::thrust::device, fi, li, fo, ::std::move(x), ::std::move(op));
}

template <typename I,
          typename O,
          typename T,
          typename Op,
          enable_if_t<!::hipstd::is_offloadable_iterator<I, O>() || !::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O exclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, T x, Op op)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I, O>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                            typename iterator_traits<O>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op>())
  {
    ::hipstd::unsupported_callable_type<Op>();
  }

  return ::std::exclusive_scan(::std::execution::par, fi, li, fo, ::std::move(x), ::std::move(op));
}
// END EXCLUSIVE_SCAN

// BEGIN INCLUSIVE_SCAN
template <typename I, typename O, typename T, enable_if_t<::hipstd::is_offloadable_iterator<I, O>()>* = nullptr>
inline O inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo)
{
  return ::thrust::inclusive_scan(::thrust::device, fi, li, fo);
}

template <typename I, typename O, typename T, enable_if_t<!::hipstd::is_offloadable_iterator<I, O>()>* = nullptr>
inline O inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo)
{
  ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                          typename iterator_traits<O>::iterator_category>();

  return ::std::inclusive_scan(::std::execution::par, fi, li, fo);
}

template <typename I,
          typename O,
          typename Op,
          enable_if_t<::hipstd::is_offloadable_iterator<I, O>() && ::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op op)
{
  return ::thrust::inclusive_scan(::thrust::device, fi, li, fo, ::std::move(op));
}

template <typename I,
          typename O,
          typename Op,
          enable_if_t<!::hipstd::is_offloadable_iterator<I, O>() || !::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op op)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I, O>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                            typename iterator_traits<O>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op>())
  {
    ::hipstd::unsupported_callable_type<Op>();
  }

  return ::std::inclusive_scan(::std::execution::par, fi, li, fo, ::std::move(op));
}

template <typename I,
          typename O,
          typename Op,
          typename T,
          enable_if_t<::hipstd::is_offloadable_iterator<I, O>() && ::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op op, T x)
{ // TODO: this is highly inefficient due to rocThrust not exposing
  //       this particular interface where the user provides x.
  if (fi == li)
  {
    return fo;
  }

  auto lo = ::thrust::inclusive_scan(::thrust::device, fi, li, fo, op);

  auto fn   = [op = ::std::move(op), x = ::std::move(x)](auto&& y) { return op(x, y); };
  using fn_t = decltype(fn);

  if constexpr (::std::is_trivially_destructible_v<fn_t>)
  {
    return ::thrust::transform(::thrust::device, fo, lo, fo, ::std::move(fn));
  }
  else
  {
    ::hipstd::detail::device_callable_guard<fn_t> guard(::std::move(fn));
    O result;
    try
    {
      result = ::thrust::transform(
        ::thrust::device, fo, lo, fo, ::hipstd::detail::callable_proxy<fn_t>{guard.get()});
    }
    catch (...)
    {
      (void) ::hipDeviceSynchronize();
      throw;
    }
    ::thrust::hip_rocprim::throw_on_error(
      ::hipDeviceSynchronize(), "hipstdpar inclusive_scan: failed to synchronize");
    guard.destroy_and_free();
    return result;
  }
}

template <typename I,
          typename O,
          typename Op,
          typename T,
          enable_if_t<!::hipstd::is_offloadable_iterator<I, O>() || !::hipstd::is_offloadable_callable<Op>()>* = nullptr>
inline O inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op op, T x)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I, O>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                            typename iterator_traits<O>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op>())
  {
    ::hipstd::unsupported_callable_type<Op>();
  }

  return ::std::inclusive_scan(::std::execution::par, fi, li, fo, ::std::move(op), ::std::move(x));
}
// END INCLUSIVE_SCAN

// BEGIN TRANSFORM_REDUCE
template <typename I0, typename I1, typename T, enable_if_t<::hipstd::is_offloadable_iterator<I0, I1>()>* = nullptr>
inline T transform_reduce(execution::parallel_unsequenced_policy, I0 f0, I0 l0, I1 f1, T x)
{
  return ::thrust::inner_product(::thrust::device, f0, l0, f1, ::std::move(x));
}

template <typename I0, typename I1, typename T, enable_if_t<!::hipstd::is_offloadable_iterator<I0, I1>()>* = nullptr>
inline T transform_reduce(execution::parallel_unsequenced_policy, I0 f0, I0 l0, I1 f1, T x)
{
  ::hipstd::unsupported_iterator_category<typename iterator_traits<I0>::iterator_category,
                                          typename iterator_traits<I1>::iterator_category>();

  return ::std::transform_reduce(::std::execution::par, f0, l0, f1, ::std::move(x));
}

template <
  typename I0,
  typename I1,
  typename T,
  typename Op0,
  typename Op1,
  enable_if_t<::hipstd::is_offloadable_iterator<I0, I1>() && ::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline T transform_reduce(execution::parallel_unsequenced_policy, I0 f0, I0 l0, I1 f1, T x, Op0 op0, Op1 op1)
{
  return ::thrust::inner_product(::thrust::device, f0, l0, f1, ::std::move(x), ::std::move(op0), ::std::move(op1));
}

template <
  typename I0,
  typename I1,
  typename T,
  typename Op0,
  typename Op1,
  enable_if_t<!::hipstd::is_offloadable_iterator<I0, I1>() || !::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline T transform_reduce(execution::parallel_unsequenced_policy, I0 f0, I0 l0, I1 f1, T x, Op0 op0, Op1 op1)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I0, I1>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I0>::iterator_category,
                                            typename iterator_traits<I1>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op0, Op1>())
  {
    ::hipstd::unsupported_callable_type<Op0, Op1>();
  }

  return ::std::transform_reduce(::std::execution::par, f0, l0, f1, ::std::move(x), ::std::move(op0), ::std::move(op1));
}

template <typename I,
          typename T,
          typename Op0,
          typename Op1,
          enable_if_t<::hipstd::is_offloadable_iterator<I>() && ::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline T transform_reduce(execution::parallel_unsequenced_policy, I f, I l, T x, Op0 op0, Op1 op1)
{
  return ::thrust::transform_reduce(::thrust::device, f, l, ::std::move(op1), ::std::move(x), ::std::move(op0));
}

template <
  typename I,
  typename T,
  typename Op0,
  typename Op1,
  enable_if_t<!::hipstd::is_offloadable_iterator<I>() || !::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline T transform_reduce(execution::parallel_unsequenced_policy, I f, I l, T x, Op0 op0, Op1 op1)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op0, Op1>())
  {
    ::hipstd::unsupported_callable_type<Op0, Op1>();
  }

  return ::std::transform_reduce(::std::execution::par, f, l, ::std::move(x), ::std::move(op0), ::std::move(op1));
}
// END TRANSFORM_REDUCE

// BEGIN TRANSFORM_EXCLUSIVE_SCAN
template <
  typename I,
  typename O,
  typename T,
  typename Op0,
  typename Op1,
  enable_if_t<::hipstd::is_offloadable_iterator<I, O>() && ::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline O transform_exclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, T x, Op0 op0, Op1 op1)
{
  return ::thrust::transform_exclusive_scan(
    ::thrust::device, fi, li, fo, ::std::move(op1), ::std::move(x), ::std::move(op0));
}

template <
  typename I,
  typename O,
  typename T,
  typename Op0,
  typename Op1,
  enable_if_t<!::hipstd::is_offloadable_iterator<I, O>() || !::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline O transform_exclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, T x, Op0 op0, Op1 op1)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I, O>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                            typename iterator_traits<O>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op0, Op1>())
  {
    ::hipstd::unsupported_callable_type<Op0, Op1>();
  }

  return ::std::transform_exclusive_scan(
    ::std::execution::par, fi, li, fo, ::std::move(x), ::std::move(op0), ::std::move(op1));
}
// END TRANSFORM_EXCLUSIVE_SCAN

// BEGIN TRANSFORM_INCLUSIVE_SCAN
template <
  typename I,
  typename O,
  typename Op0,
  typename Op1,
  enable_if_t<::hipstd::is_offloadable_iterator<I, O>() && ::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline O transform_inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op0 op0, Op1 op1)
{
  return ::thrust::transform_inclusive_scan(::thrust::device, fi, li, fo, ::std::move(op1), ::std::move(op0));
}

template <
  typename I,
  typename O,
  typename Op0,
  typename Op1,
  enable_if_t<!::hipstd::is_offloadable_iterator<I, O>() || !::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline O transform_inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op0 op0, Op1 op1)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I, O>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                            typename iterator_traits<O>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op0, Op1>())
  {
    ::hipstd::unsupported_callable_type<Op0, Op1>();
  }

  return ::std::transform_inclusive_scan(::std::execution::par, fi, li, fo, ::std::move(op0), ::std::move(op1));
}

template <
  typename I,
  typename O,
  typename Op0,
  typename Op1,
  typename T,
  enable_if_t<::hipstd::is_offloadable_iterator<I, O>() && ::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline O transform_inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op0 op0, Op1 op1, T x)
{ // TODO: this is inefficient.
  if (fi == li)
  {
    return fo;
  }

  auto lo = ::thrust::transform_inclusive_scan(::thrust::device, fi, li, fo, ::std::move(op1), op0);

  auto fn    = [op0 = ::std::move(op0), x = ::std::move(x)](auto&& y) { return op0(x, y); };
  using fn_t = decltype(fn);

  if constexpr (::std::is_trivially_destructible_v<fn_t>)
  {
    return ::thrust::transform(::thrust::device, fo, lo, fo, ::std::move(fn));
  }
  else
  {
    ::hipstd::detail::device_callable_guard<fn_t> guard(::std::move(fn));
    O result;
    try
    {
      result = ::thrust::transform(
        ::thrust::device, fo, lo, fo, ::hipstd::detail::callable_proxy<fn_t>{guard.get()});
    }
    catch (...)
    {
      (void) ::hipDeviceSynchronize();
      throw;
    }
    ::thrust::hip_rocprim::throw_on_error(
      ::hipDeviceSynchronize(), "hipstdpar transform_inclusive_scan: failed to synchronize");
    guard.destroy_and_free();
    return result;
  }
}

template <
  typename I,
  typename O,
  typename Op0,
  typename Op1,
  typename T,
  enable_if_t<!::hipstd::is_offloadable_iterator<I, O>() || !::hipstd::is_offloadable_callable<Op0, Op1>()>* = nullptr>
inline O transform_inclusive_scan(execution::parallel_unsequenced_policy, I fi, I li, O fo, Op0 op0, Op1 op1, T x)
{
  if constexpr (!::hipstd::is_offloadable_iterator<I, O>())
  {
    ::hipstd::unsupported_iterator_category<typename iterator_traits<I>::iterator_category,
                                            typename iterator_traits<O>::iterator_category>();
  }
  if constexpr (!::hipstd::is_offloadable_callable<Op0, Op1>())
  {
    ::hipstd::unsupported_callable_type<Op0, Op1>();
  }

  return ::std::transform_inclusive_scan(
    ::std::execution::par, fi, li, fo, ::std::move(op0), ::std::move(op1), ::std::move(x));
}
// END TRANSFORM_INCLUSIVE_SCAN
} // namespace std
#else // __HIPSTDPAR__
#  error "__HIPSTDPAR__ should be defined. Please use the '--hipstdpar' compile option."
#endif // __HIPSTDPAR__
