//============================================================================
//  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_arc_comparator_h
#define vtk_m_worklet_contourtree_augmented_contourtree_mesh_inc_arc_comparator_h

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

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


// comparator used for initial sort of data values
class ArcComparatorImpl
{
public:
  using IdPortalType = vtkm::cont::ArrayHandle<vtkm::Id>::ReadPortalType;

  // constructor - takes vectors as parameters
  VTKM_CONT
  ArcComparatorImpl(const IdArrayType& ct_arcs,
                    vtkm::cont::DeviceAdapterId device,
                    vtkm::cont::Token& token)
    : ArcsPortal(ct_arcs.PrepareForInput(device, token))
  {
  }

  // () operator - gets called to do comparison
  VTKM_EXEC
  bool operator()(const vtkm::Id& x, const vtkm::Id& y) const
  { // operator()
    vtkm::Id from1 = (x % 2 == 0) ? x / 2 : MaskedIndex(ArcsPortal.Get(x / 2));
    vtkm::Id from2 = (y % 2 == 0) ? y / 2 : MaskedIndex(ArcsPortal.Get(y / 2));
    if (from1 != from2)
    {
      return from1 < from2;
    }
    else
    {
      vtkm::Id to1 = (x % 2 == 0) ? MaskedIndex(ArcsPortal.Get(x / 2)) : x / 2;
      vtkm::Id to2 = (y % 2 == 0) ? MaskedIndex(ArcsPortal.Get(y / 2)) : y / 2;
      return to1 < to2;
    }
  } // operator()

private:
  IdPortalType ArcsPortal;

}; // ArcComparator

class ArcComparator : public vtkm::cont::ExecutionObjectBase
{
public:
  // constructor - takes vectors as parameters
  VTKM_CONT
  ArcComparator(const IdArrayType& arcs)
    : Arcs(arcs)
  {
  }

  VTKM_CONT ArcComparatorImpl PrepareForExecution(vtkm::cont::DeviceAdapterId device,
                                                  vtkm::cont::Token& token) const
  {
    return ArcComparatorImpl(this->Arcs, device, token);
  }

private:
  IdArrayType Arcs;
}; // EdgePeakComparator


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

#endif
