//============================================================================
//  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 (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 vtkm_worklet_contourtree_augmented_active_graph_set_hyper_arcs_worklet_h
#define vtkm_worklet_contourtree_augmented_active_graph_set_hyper_arcs_worklet_h

#include <vtkm/worklet/WorkletMapField.h>
#include <vtkm/worklet/contourtree_augmented/Types.h>

namespace vtkm
{
namespace worklet
{
namespace contourtree_augmented
{
namespace active_graph_inc
{

// Worklet for computing the sort indices from the sort order
class SetHyperArcsWorklet : public vtkm::worklet::WorkletMapField
{
public:
  typedef void ControlSignature(
    WholeArrayInOut treeHypernodes, // (input/output) hypernodes of the tree
    WholeArrayOut treeHyperarcs,    // (output) tree hyperarcs
    WholeArrayIn graphHyperarcs,    // (input) hyperarcs from the portal
    WholeArrayIn graphSuperID);     // (input) active graph superID
  typedef void ExecutionSignature(_1, InputIndex, _2, _3, _4);
  using InputDomain = _1;

  // Default Constructor
  VTKM_EXEC_CONT
  SetHyperArcsWorklet() {}

  template <typename InFieldPortalType, typename InOutFieldPortalType, typename OutFieldPortalType>
  VTKM_EXEC void operator()(const InOutFieldPortalType& treeHypernodesPortal,
                            const vtkm::Id hypernode,
                            const OutFieldPortalType treeHyperarcsPortal,
                            const InFieldPortalType& graphHyperarcsPortal,
                            const InFieldPortalType& graphSuperIDPortal) const
  {
    // reset the hypernode ID to a supernode ID from a graph ID
    vtkm::Id graphID = treeHypernodesPortal.Get(hypernode);
    treeHypernodesPortal.Set(hypernode, graphSuperIDPortal.Get(graphID));

    // now retrieve the hyperarc destination
    vtkm::Id graphTarget = graphHyperarcsPortal.Get(graphID);
    // if it's the global minimum, copy
    if (noSuchElement(graphTarget))
      treeHyperarcsPortal.Set(hypernode, (vtkm::Id)NO_SUCH_ELEMENT);
    // otherwise, look up the correct supernode ID
    else
      treeHyperarcsPortal.Set(hypernode, graphSuperIDPortal.Get(maskedIndex(graphTarget)));
    // and reset the hypernode ID to a supernode ID

    // In serial this worklet implements the following operation
    /*
       for (indexType hypernode = 0; hypernode < nHypernodes; hypernode++)
        { // per hypernode
          // reset the hypernode ID to a supernode ID from a graph ID
          indexType graphID = tree.hypernodes[hypernode];
          tree.hypernodes[hypernode] = superID[graphID];

          // now retrieve the hyperarc destination
          indexType graphTarget = hyperarcs[graphID];
          // if it's the global minimum, copy
          if (noSuchElement(graphTarget))
                  tree.hyperarcs[hypernode] = NO_SUCH_ELEMENT;
          // otherwise, look up the correct supernode ID
          else
                  tree.hyperarcs[hypernode] = superID[maskedIndex(graphTarget)];
          // and reset the hypernode ID to a supernode ID
        } // per hypernode
      */
  }

}; // SetHyperArcsWorklet

} // namespace active_graph_inc
} // namespace contourtree_augmented
} // namespace worklet
} // namespace vtkm

#endif
