//============================================================================
//  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 2014 National Technology & Engineering Solutions of Sandia, LLC (NTESS).
//  Copyright 2014 UT-Battelle, LLC.
//  Copyright 2014 Los Alamos National Security.
//
//  Under the terms of Contract DE-NA0003525 with NTESS,
//  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.
//============================================================================
// Copyright (c) 2018, The Regents of the University of California, through
// Lawrence Berkeley National Laboratory (subject to receipt of any required approvals
// from the U.S. Dept. of Energy).  All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// (1) Redistributions of source code must retain the above copyright notice, this
//     list of conditions and the following disclaimer.
//
// (2) 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.
//
// (3) Neither the name of the University of California, Lawrence Berkeley National
//     Laboratory, U.S. Dept. of Energy 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 THE COPYRIGHT OWNER OR CONTRIBUTORS 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.
//
//=============================================================================
//
//  This code is an extension of the algorithm presented in the paper:
//  Parallel Peak Pruning for Scalable SMP Contour Tree Computation.
//  Hamish Carr, Gunther Weber, Christopher Sewell, and James Ahrens.
//  Proceedings of the IEEE Symposium on Large Data Analysis and Visualization
//  (LDAV), October 2016, Baltimore, Maryland.
//
//  The PPP2 algorithm and software were jointly developed by
//  Hamish Carr (University of Leeds), Gunther H. Weber (LBNL), and
//  Oliver Ruebel (LBNL)
//==============================================================================

#ifndef vtk_m_worklet_contourtree_augmented_contourtree_mesh_inc_combined_simulated_simplicity_index_comparator_h
#define vtk_m_worklet_contourtree_augmented_contourtree_mesh_inc_combined_simulated_simplicity_index_comparator_h

#include <vtkm/cont/ArrayHandle.h>
#include <vtkm/filter/scalar_topology/worklet/contourtree_augmented/Types.h>

namespace vtkm
{
namespace worklet
{
namespace contourtree_augmented
{
namespace mesh_dem_contourtree_mesh_inc
{


/// Implementation of the comparator used initial sort of data values in ContourTreeMesh<FieldType>::MergeWith
template <typename FieldType>
class CombinedSimulatedSimplicityIndexComparatorImpl
{
public:
  using IdPortalType = typename vtkm::cont::ArrayHandle<vtkm::Id>::ReadPortalType;
  using ValuePortalType = typename vtkm::cont::ArrayHandle<FieldType>::ReadPortalType;

  VTKM_CONT
  CombinedSimulatedSimplicityIndexComparatorImpl(
    const IdArrayType& thisGlobalMeshIndex,
    const IdArrayType& otherGlobalMeshIndex,
    const vtkm::cont::ArrayHandle<FieldType>& thisSortedValues,
    const vtkm::cont::ArrayHandle<FieldType>& otherSortedValues,
    vtkm::cont::DeviceAdapterId device,
    vtkm::cont::Token& token)
  {
    this->ThisGlobalMeshIndex = thisGlobalMeshIndex.PrepareForInput(device, token);
    this->OtherGlobalMeshIndex = otherGlobalMeshIndex.PrepareForInput(device, token);
    ;
    this->ThisSortedValues = thisSortedValues.PrepareForInput(device, token);
    this->OtherSortedValues = otherSortedValues.PrepareForInput(device, token);
  }

  VTKM_EXEC_CONT
  inline vtkm::Id GetGlobalMeshIndex(vtkm::Id idx) const
  {
    return vtkm::worklet::contourtree_augmented::IsThis(idx)
      ? this->ThisGlobalMeshIndex.Get(MaskedIndex(idx))
      : this->OtherGlobalMeshIndex.Get(MaskedIndex(idx));
  }

  VTKM_EXEC_CONT
  inline FieldType GetSortedValue(vtkm::Id idx) const
  {
    return vtkm::worklet::contourtree_augmented::IsThis(idx)
      ? this->ThisSortedValues.Get(MaskedIndex(idx))
      : this->OtherSortedValues.Get(MaskedIndex(idx));
  }

  VTKM_EXEC_CONT
  bool operator()(vtkm::Id i, vtkm::Id j) const
  { // operator()
    // get values
    FieldType val_i = this->GetSortedValue(i);
    FieldType val_j = this->GetSortedValue(j);

    // value comparison
    if (val_i < val_j)
    {
      return true;
    }
    if (val_j < val_i)
    {
      return false;
    }

    // get indices
    vtkm::Id idx_i = this->GetGlobalMeshIndex(i);
    vtkm::Id idx_j = this->GetGlobalMeshIndex(j);
    // index comparison for simulated simplicity
    if (idx_i < idx_j)
    {
      return true;
    }
    if (idx_j < idx_i)
    {
      return false;
    }

    // fallback - always false
    return false;

    /** //Original code
          { // operator()
            // get Values
            dataType val_i = Values[i];
            dataType val_j = Values[j];

            // value comparison
            if (val_i < val_j)
                return true;
            if (val_j < val_i)
                return false;

            // get Indices
            indexType idx_i = Indices[i];
            indexType idx_j = Indices[j];
            // index comparison for simulated simplicity
            if (idx_i < idx_j)
                return true;
            if (idx_j < idx_i)
                return false;

            // fallback - always false
            return false;
        } // operator()

          */


  } // operator()

private:
  IdPortalType ThisGlobalMeshIndex;
  IdPortalType OtherGlobalMeshIndex;
  ValuePortalType ThisSortedValues;
  ValuePortalType OtherSortedValues;
};


/// Execution object for the comparator used initial sort of data values in ContourTreeMesh<FieldType>::MergeWith
template <typename FieldType>
class CombinedSimulatedSimplicityIndexComparator : public vtkm::cont::ExecutionObjectBase
{
public:
  // constructor
  VTKM_CONT
  CombinedSimulatedSimplicityIndexComparator(
    const IdArrayType& thisGlobalMeshIndex,
    const IdArrayType& otherGlobalMeshIndex,
    const vtkm::cont::ArrayHandle<FieldType>& thisSortedValues,
    const vtkm::cont::ArrayHandle<FieldType>& otherSortedValues)
    : ThisGlobalMeshIndex(thisGlobalMeshIndex)
    , OtherGlobalMeshIndex(otherGlobalMeshIndex)
    , ThisSortedValues(thisSortedValues)
    , OtherSortedValues(otherSortedValues)
  {
  }

  VTKM_CONT CombinedSimulatedSimplicityIndexComparatorImpl<FieldType> PrepareForExecution(
    vtkm::cont::DeviceAdapterId device,
    vtkm::cont::Token& token)
  {
    return CombinedSimulatedSimplicityIndexComparatorImpl<FieldType>(this->ThisGlobalMeshIndex,
                                                                     this->OtherGlobalMeshIndex,
                                                                     this->ThisSortedValues,
                                                                     this->OtherSortedValues,
                                                                     device,
                                                                     token);
  }

private:
  IdArrayType ThisGlobalMeshIndex;
  IdArrayType OtherGlobalMeshIndex;
  vtkm::cont::ArrayHandle<FieldType> ThisSortedValues;
  vtkm::cont::ArrayHandle<FieldType> OtherSortedValues;

}; // CombinedSimulatedSimplicityIndexComparator

} // namespace mesh_dem_contourtree_mesh_inc
} // namespace contourtree_augmented
} // namespace worklet
} // namespace vtkm

#endif
