
//  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) 2016, Los Alamos National Security, LLC
//  All rights reserved.
//
//  Copyright 2016. Los Alamos National Security, LLC.
//  This software was produced under U.S. Government contract DE-AC52-06NA25396
//  for Los Alamos National Laboratory (LANL), which is operated by
//  Los Alamos National Security, LLC for the U.S. Department of Energy.
//  The U.S. Government has rights to use, reproduce, and distribute this
//  software.  NEITHER THE GOVERNMENT NOR LOS ALAMOS NATIONAL SECURITY, LLC
//  MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY LIABILITY FOR THE
//  USE OF THIS SOFTWARE.  If software is modified to produce derivative works,
//  such modified software should be clearly marked, so as not to confuse it
//  with the version available from LANL.
//
//  Additionally, 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 Los Alamos National Security, LLC, Los Alamos
//     National Laboratory, LANL, the U.S. Government, 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 LOS ALAMOS NATIONAL SECURITY, LLC 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 LOS ALAMOS
//  NATIONAL SECURITY, LLC 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.
//============================================================================

#ifndef vtkm_worklet_cosmotools_mark_active_neighbors_h
#define vtkm_worklet_cosmotools_mark_active_neighbors_h

#include <vtkm/worklet/WorkletMapField.h>
#include <vtkm/worklet/cosmotools/TagTypes.h>

namespace vtkm
{
namespace worklet
{
namespace cosmotools
{
// Worklet for particles to indicate which neighbors are active
// because at least one particle in that bin is within linking length
template <typename T>
class MarkActiveNeighbors : public vtkm::worklet::WorkletMapField
{
public:
  typedef void ControlSignature(
    FieldIn<IdType> index,                 // (input) particle index
    FieldIn<IdType> partId,                // (input) particle id sorted
    FieldIn<IdType> binId,                 // (input) bin Id per particle
    WholeArrayIn<IdType> partIdArray,      // (input) sequence imposed on sorted particle Ids
    WholeArrayIn<Vec3TagType<T>> location, // (input) location of particles
    WholeArrayIn<IdType> firstPartId,      // (input) vector of first particle indices
    WholeArrayIn<IdType> lastPartId,       // (input) vector of last particle indices
    FieldOut<UInt32TagType> flag);         // (output) active bin neighbors mask
  typedef _8 ExecutionSignature(_1, _2, _3, _4, _5, _6, _7);
  using InputDomain = _1;

  vtkm::Id xNum, yNum, zNum;
  vtkm::Id NUM_NEIGHBORS;
  T linkLenSq;

  // Constructor
  VTKM_EXEC_CONT
  MarkActiveNeighbors(const vtkm::Id XNum,
                      const vtkm::Id YNum,
                      const vtkm::Id ZNum,
                      const vtkm::Id NumNeighbors,
                      const T LinkLen)
    : xNum(XNum)
    , yNum(YNum)
    , zNum(ZNum)
    , NUM_NEIGHBORS(NumNeighbors)
    , linkLenSq(LinkLen * LinkLen)
  {
  }

  template <typename InIdPortalType, typename InFieldPortalType, typename InVectorPortalType>
  VTKM_EXEC vtkm::UInt32 operator()(const vtkm::Id& i,
                                    const vtkm::Id& iPartId,
                                    const vtkm::Id& iBinId,
                                    const InIdPortalType& partIdArray,
                                    const InFieldPortalType& location,
                                    const InVectorPortalType& firstPartId,
                                    const InVectorPortalType& lastPartId) const
  {
    const vtkm::Id ybin = (iBinId / xNum) % yNum;
    const vtkm::Id zbin = iBinId / (xNum * yNum);
    vtkm::UInt32 activeFlag = 0;
    vtkm::UInt32 bcnt = 1;
    vtkm::Id cnt = 0;

    // Examine all neighbor bins surrounding this particle
    for (vtkm::Id z = zbin - 1; z <= zbin + 1; z++)
    {
      for (vtkm::Id y = ybin - 1; y <= ybin + 1; y++)
      {
        if ((y >= 0) && (y < yNum) && (z >= 0) && (z < zNum))
        {
          vtkm::Id pos = NUM_NEIGHBORS * i + cnt;
          vtkm::Id startParticle = firstPartId.Get(pos);
          vtkm::Id endParticle = lastPartId.Get(pos);

          // If the bin has any particles, check to see if any of those
          // are within the linking length from this particle
          for (vtkm::Id j = startParticle; j < endParticle; j++)
          {
            vtkm::Id jPartId = partIdArray.Get(j);
            vtkm::Vec<T, 3> iloc = location.Get(iPartId);
            vtkm::Vec<T, 3> jloc = location.Get(jPartId);
            T xDist = iloc[0] - jloc[0];
            T yDist = iloc[1] - jloc[1];
            T zDist = iloc[2] - jloc[2];

            // Found a particle within linking length so this bin is active
            if ((xDist * xDist + yDist * yDist + zDist * zDist) <= linkLenSq)
            {
              activeFlag = activeFlag | bcnt;
              break;
            }
          }
        }
        bcnt = bcnt << 1;
        cnt++;
      }
    }
    return activeFlag;
  }
}; // MarkActiveNeighbors
}
}
}

#endif
