//============================================================================
//  Copyright (c) Kitware, Inc.
//  All rights reserved.
//  See LICENSE.txt for details.
//  This software is distributed WITHOUT ANY WARRANTY; without even
//  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
//  PURPOSE.  See the above copyright notice for more information.
//
//  Copyright 2016 Sandia Corporation.
//  Copyright 2016 UT-Battelle, LLC.
//  Copyright 2016 Los Alamos National Security.
//
//  Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
//  the U.S. Government retains certain rights in this software.
//
//  Under the terms of Contract DE-AC52-06NA25396 with Los Alamos National
//  Laboratory (LANL), the U.S. Government retains certain rights in
//  this software.
//============================================================================
#ifndef vtk_m_exec_internal_ReduceByKeyLookup_h
#define vtk_m_exec_internal_ReduceByKeyLookup_h

#include <vtkm/exec/ExecutionObjectBase.h>

#include <vtkm/StaticAssert.h>
#include <vtkm/Types.h>

#include <type_traits>

namespace vtkm {
namespace exec {
namespace internal {

/// \breif Execution object holding lookup info for reduce by key.
///
/// A WorkletReduceByKey needs several arrays to map the current output object
/// to the respective key and group of values. This execution object holds that
/// state.
///
template<typename KeyPortalType,
         typename IdPortalType,
         typename IdComponentPortalType>
struct ReduceByKeyLookup : vtkm::exec::ExecutionObjectBase
{
  using KeyType = typename KeyPortalType::ValueType;

  VTKM_STATIC_ASSERT(
      (std::is_same<typename IdPortalType::ValueType, vtkm::Id>::value));
  VTKM_STATIC_ASSERT(
      (std::is_same<typename IdComponentPortalType::ValueType, vtkm::IdComponent>::value));

  KeyPortalType UniqueKeys;
  IdPortalType SortedValuesMap;
  IdPortalType Offsets;
  IdComponentPortalType Counts;

  VTKM_EXEC_CONT
  ReduceByKeyLookup(const KeyPortalType &uniqueKeys,
                    const IdPortalType &sortedValuesMap,
                    const IdPortalType &offsets,
                    const IdComponentPortalType &counts)
    : UniqueKeys(uniqueKeys),
      SortedValuesMap(sortedValuesMap),
      Offsets(offsets),
      Counts(counts)
  {  }

  VTKM_EXEC_CONT
  ReduceByKeyLookup()
  {  }
};

}
}
} // namespace vtkm::exec::internal

#endif //vtk_m_exec_internal_ReduceByKeyLookup_h
