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 *       names of its contributors may be used to endorse or promote products
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#pragma once

#if THRUST_DEVICE_COMPILER == THRUST_DEVICE_COMPILER_HCC
#include <thrust/system/hip/detail/util.h>

#include <thrust/detail/minmax.h>
#include <thrust/detail/mpl/math.h>
#include <thrust/distance.h>
#include <thrust/system/hip/detail/memory_buffer.h>
#include <thrust/system/hip/detail/par_to_seq.h>
#include <thrust/system/hip/execution_policy.h>

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

BEGIN_NS_THRUST
namespace hip_rocprim
{
namespace __scan_by_key
{
    template <class Policy,
              class KeysInputIterator,
              class ValuesInputIterator,
              class ValuesOutputIterator,
              class KeyCompareFunction = ::rocprim::equal_to<
                  typename std::iterator_traits<KeysInputIterator>::value_type>,
              class BinaryFunction
              = ::rocprim::plus<typename std::iterator_traits<ValuesInputIterator>::value_type>>
    ValuesOutputIterator THRUST_HIP_RUNTIME_FUNCTION
    inclusive_scan_by_key(Policy&              policy,
                          KeysInputIterator    key_first,
                          KeysInputIterator    key_last,
                          ValuesInputIterator  value_first,
                          ValuesOutputIterator value_result,
                          KeyCompareFunction   key_compare_op,
                          BinaryFunction       scan_op)
    {
        size_t      num_items      = static_cast<size_t>(thrust::distance(key_first, key_last));
        void*       d_temp_storage = nullptr;
        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 value_result;

        // Determine temporary device storage requirements.
        hip_rocprim::throw_on_error(rocprim::inclusive_scan_by_key(d_temp_storage,
                                                                   temp_storage_bytes,
                                                                   key_first,
                                                                   value_first,
                                                                   value_result,
                                                                   num_items,
                                                                   scan_op,
                                                                   key_compare_op,
                                                                   stream,
                                                                   debug_sync),
                                    "scan_by_key failed on 1st step");

        // Allocate temporary storage.
        d_temp_storage = hip_rocprim::get_memory_buffer(policy, temp_storage_bytes);
        hip_rocprim::throw_on_error(hipGetLastError(),
                                    "scan_by_key failed to get memory buffer");

        // Run scan.
        hip_rocprim::throw_on_error(rocprim::inclusive_scan_by_key(d_temp_storage,
                                                                   temp_storage_bytes,
                                                                   key_first,
                                                                   value_first,
                                                                   value_result,
                                                                   num_items,
                                                                   scan_op,
                                                                   key_compare_op,
                                                                   stream,
                                                                   debug_sync),
                                    "scan_by_key failed on 2nd step");

        hip_rocprim::return_memory_buffer(policy, d_temp_storage);
        hip_rocprim::throw_on_error(hipGetLastError(),
                                    "scan_by_key failed to return memory buffer");

        return value_result + num_items;
    }

    template <class Policy,
              class KeysInputIterator,
              class ValuesInputIterator,
              class ValuesOutputIterator,
              class InitialValueType,
              class KeyCompareFunction = ::rocprim::equal_to<
                  typename std::iterator_traits<KeysInputIterator>::value_type>,
              class BinaryFunction
              = ::rocprim::plus<typename std::iterator_traits<ValuesInputIterator>::value_type>>
    ValuesOutputIterator THRUST_HIP_RUNTIME_FUNCTION
    exclusive_scan_by_key(Policy&              policy,
                          KeysInputIterator    key_first,
                          KeysInputIterator    key_last,
                          ValuesInputIterator  value_first,
                          ValuesOutputIterator value_result,
                          InitialValueType     init,
                          KeyCompareFunction   key_compare_op,
                          BinaryFunction       scan_op)
    {
        size_t      num_items      = static_cast<size_t>(thrust::distance(key_first, key_last));
        void*       d_temp_storage = nullptr;
        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 value_result;

        // Determine temporary device storage requirements.
        hip_rocprim::throw_on_error(rocprim::exclusive_scan_by_key(d_temp_storage,
                                                                   temp_storage_bytes,
                                                                   key_first,
                                                                   value_first,
                                                                   value_result,
                                                                   init,
                                                                   num_items,
                                                                   scan_op,
                                                                   key_compare_op,
                                                                   stream,
                                                                   debug_sync),
                                    "scan_by_key failed on 1st step");

        // Allocate temporary storage.
        d_temp_storage = hip_rocprim::get_memory_buffer(policy, temp_storage_bytes);
        hip_rocprim::throw_on_error(hipGetLastError(),
                                    "scan_by_key failed to get memory buffer");

        // Run scan.
        hip_rocprim::throw_on_error(rocprim::exclusive_scan_by_key(d_temp_storage,
                                                                   temp_storage_bytes,
                                                                   key_first,
                                                                   value_first,
                                                                   value_result,
                                                                   init,
                                                                   num_items,
                                                                   scan_op,
                                                                   key_compare_op,
                                                                   stream,
                                                                   debug_sync),
                                    "scan_by_key failed on 2nd step");

        hip_rocprim::return_memory_buffer(policy, d_temp_storage);
        hip_rocprim::throw_on_error(hipGetLastError(),
                                    "scan_by_key failed to return memory buffer");

        return value_result + num_items;
    }
} // namspace scan_by_key

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

//---------------------------
//   Inclusive scan
//---------------------------

__thrust_exec_check_disable__ template <class Derived,
                                        class KeyInputIt,
                                        class ValInputIt,
                                        class ValOutputIt,
                                        class BinaryPred,
                                        class ScanOp>
ValOutputIt THRUST_HIP_FUNCTION
inclusive_scan_by_key(execution_policy<Derived>& policy,
                      KeyInputIt                 key_first,
                      KeyInputIt                 key_last,
                      ValInputIt                 value_first,
                      ValOutputIt                value_result,
                      BinaryPred                 binary_pred,
                      ScanOp                     scan_op)
{
    ValOutputIt ret = value_result;
    THRUST_HIP_PRESERVE_KERNELS_WORKAROUND(
        (__scan_by_key::inclusive_scan_by_key<Derived,
                                              KeyInputIt,
                                              ValInputIt,
                                              ValOutputIt,
                                              BinaryPred,
                                              ScanOp>)
    );
#if __THRUST_HAS_HIPRT__
    ret = __scan_by_key::inclusive_scan_by_key(
        policy, key_first, key_last, value_first, value_result, binary_pred, scan_op
    );
#else
    ret = thrust::inclusive_scan_by_key(cvt_to_seq(derived_cast(policy)),
                                        key_first,
                                        key_last,
                                        value_first,
                                        value_result,
                                        binary_pred,
                                        scan_op);
#endif
    return ret;
}

template <class Derived,
          class KeyInputIt,
          class ValInputIt,
          class ValOutputIt,
          class BinaryPred>
ValOutputIt THRUST_HIP_FUNCTION
inclusive_scan_by_key(execution_policy<Derived>& policy,
                      KeyInputIt                 key_first,
                      KeyInputIt                 key_last,
                      ValInputIt                 value_first,
                      ValOutputIt                value_result,
                      BinaryPred                 binary_pred)
{
    typedef typename thrust::iterator_traits<ValOutputIt>::value_type value_type;
    return hip_rocprim::inclusive_scan_by_key(policy,
                                              key_first,
                                              key_last,
                                              value_first,
                                              value_result,
                                              binary_pred,
                                              plus<value_type>());
}

template <class Derived, class KeyInputIt, class ValInputIt, class ValOutputIt>
ValOutputIt THRUST_HIP_FUNCTION
inclusive_scan_by_key(execution_policy<Derived>& policy,
                      KeyInputIt                 key_first,
                      KeyInputIt                 key_last,
                      ValInputIt                 value_first,
                      ValOutputIt                value_result)
{
    typedef typename thrust::iterator_traits<KeyInputIt>::value_type key_type;
    return hip_rocprim::inclusive_scan_by_key(
        policy, key_first, key_last, value_first, value_result, equal_to<key_type>()
    );
}

//---------------------------
//   Exclusive scan
//---------------------------

__thrust_exec_check_disable__ template <class Derived,
                                        class KeyInputIt,
                                        class ValInputIt,
                                        class ValOutputIt,
                                        class Init,
                                        class BinaryPred,
                                        class ScanOp>
ValOutputIt THRUST_HIP_FUNCTION
exclusive_scan_by_key(execution_policy<Derived>& policy,
                      KeyInputIt                 key_first,
                      KeyInputIt                 key_last,
                      ValInputIt                 value_first,
                      ValOutputIt                value_result,
                      Init                       init,
                      BinaryPred                 binary_pred,
                      ScanOp                     scan_op)
{
    ValOutputIt ret = value_result;
    THRUST_HIP_PRESERVE_KERNELS_WORKAROUND(
        (__scan_by_key::exclusive_scan_by_key<Derived,
                                              KeyInputIt,
                                              ValInputIt,
                                              ValOutputIt,
                                              Init,
                                              BinaryPred,
                                              ScanOp>)
    );
#if __THRUST_HAS_HIPRT__
    ret = __scan_by_key::exclusive_scan_by_key(
        policy, key_first, key_last, value_first, value_result, init, binary_pred, scan_op);
#else
    ret = thrust::exclusive_scan_by_key(cvt_to_seq(derived_cast(policy)),
                                        key_first,
                                        key_last,
                                        value_first,
                                        value_result,
                                        init,
                                        binary_pred,
                                        scan_op);
#endif // __THRUST_HAS_HIPRT__
    return ret;
}

template <class Derived,
          class KeyInputIt,
          class ValInputIt,
          class ValOutputIt,
          class Init,
          class BinaryPred>
ValOutputIt THRUST_HIP_FUNCTION
exclusive_scan_by_key(execution_policy<Derived>& policy,
                      KeyInputIt                 key_first,
                      KeyInputIt                 key_last,
                      ValInputIt                 value_first,
                      ValOutputIt                value_result,
                      Init                       init,
                      BinaryPred                 binary_pred)
{
    return hip_rocprim::exclusive_scan_by_key(policy,
                                              key_first,
                                              key_last,
                                              value_first,
                                              value_result,
                                              init,
                                              binary_pred,
                                              plus<Init>());
}

template <class Derived, class KeyInputIt, class ValInputIt, class ValOutputIt, class Init>
ValOutputIt THRUST_HIP_FUNCTION
exclusive_scan_by_key(execution_policy<Derived>& policy,
                      KeyInputIt                 key_first,
                      KeyInputIt                 key_last,
                      ValInputIt                 value_first,
                      ValOutputIt                value_result,
                      Init                       init)
{
    typedef typename iterator_traits<KeyInputIt>::value_type key_type;
    return hip_rocprim::exclusive_scan_by_key(
        policy, key_first, key_last, value_first, value_result, init, equal_to<key_type>()
    );
}

template <class Derived, class KeyInputIt, class ValInputIt, class ValOutputIt>
ValOutputIt THRUST_HIP_FUNCTION
exclusive_scan_by_key(execution_policy<Derived>& policy,
                      KeyInputIt                 key_first,
                      KeyInputIt                 key_last,
                      ValInputIt                 value_first,
                      ValOutputIt                value_result)
{
    typedef typename iterator_traits<ValOutputIt>::value_type value_type;
    return hip_rocprim::exclusive_scan_by_key(
        policy, key_first, key_last, value_first, value_result, value_type(0)
    );
}

} // namespace hip_rocprim
END_NS_THRUST

#include <thrust/scan.h>

#endif