//============================================================================
//  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 vtk_m_worklet_contourtree_distributed_spatialdecomposition_h
#define vtk_m_worklet_contourtree_distributed_spatialdecomposition_h

#include <vtkm/Types.h>
#include <vtkm/cont/BoundsCompute.h>
#include <vtkm/cont/BoundsGlobalCompute.h>
#include <vtkm/cont/EnvironmentTracker.h>
#include <vtkm/cont/PartitionedDataSet.h>

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

// clang-format off
VTKM_THIRDPARTY_PRE_INCLUDE
#include <vtkm/thirdparty/diy/diy.h>
VTKM_THIRDPARTY_POST_INCLUDE
// clang-format on

namespace vtkm
{
namespace worklet
{
namespace contourtree_distributed
{

// --- Helper class to store the spatial decomposition defined by the PartitionedDataSet input data
class SpatialDecomposition
{
public:
  VTKM_CONT
  SpatialDecomposition(vtkm::Id3 blocksPerDim,
                       vtkm::Id3 globalSize,
                       const vtkm::cont::ArrayHandle<vtkm::Id3>& localBlockIndices,
                       const vtkm::cont::ArrayHandle<vtkm::Id3>& localBlockOrigins,
                       const vtkm::cont::ArrayHandle<vtkm::Id3>& localBlockSizes)
    : BlocksPerDimension(blocksPerDim)
    , GlobalSize(globalSize)
    , LocalBlockIndices(localBlockIndices)
    , LocalBlockOrigins(localBlockOrigins)
    , LocalBlockSizes(localBlockSizes)
  {
  }

  inline vtkmdiy::DiscreteBounds GetVTKmDIYBounds() const
  {
    if (this->NumberOfDimensions() == 2)
    {
      vtkmdiy::DiscreteBounds domain(2);
      domain.min[0] = domain.min[1] = 0;
      domain.max[0] = static_cast<int>(this->GlobalSize[0]);
      domain.max[1] = static_cast<int>(this->GlobalSize[1]);
      return domain;
    }
    else
    {
      vtkmdiy::DiscreteBounds domain(3);
      domain.min[0] = domain.min[1] = domain.min[2] = 0;
      domain.max[0] = static_cast<int>(this->GlobalSize[0]);
      domain.max[1] = static_cast<int>(this->GlobalSize[1]);
      domain.max[2] = static_cast<int>(this->GlobalSize[2]);
      return domain;
    }
  }

  inline vtkm::Id NumberOfDimensions() const { return GlobalSize[2] > 1 ? 3 : 2; }

  inline vtkm::Id GetGlobalNumberOfBlocks() const
  {
    return BlocksPerDimension[0] * BlocksPerDimension[1] * BlocksPerDimension[2];
  }

  inline vtkm::Id GetLocalNumberOfBlocks() const { return LocalBlockSizes.GetNumberOfValues(); }

  inline static vtkm::Bounds GetGlobalBounds(const vtkm::cont::PartitionedDataSet& input)
  {
    // Get the  spatial bounds  of a multi -block  data  set
    vtkm::Bounds bounds = vtkm::cont::BoundsGlobalCompute(input);
    return bounds;
  }

  inline static vtkm::Bounds GetLocalBounds(const vtkm::cont::PartitionedDataSet& input)
  {
    // Get the spatial bounds  of a multi -block  data  set
    vtkm::Bounds bounds = vtkm::cont::BoundsCompute(input);
    return bounds;
  }

  inline static vtkm::Id GetGlobalNumberOfBlocks(const vtkm::cont::PartitionedDataSet& input)
  {
    auto comm = vtkm::cont::EnvironmentTracker::GetCommunicator();
    vtkm::Id localSize = input.GetNumberOfPartitions();
    vtkm::Id globalSize = 0;
#ifdef VTKM_ENABLE_MPI
    vtkmdiy::mpi::all_reduce(comm, localSize, globalSize, std::plus<vtkm::Id>{});
#else
    globalSize = localSize;
#endif
    return globalSize;
  }

  // Number of blocks along each dimension
  vtkm::Id3 BlocksPerDimension;
  // Size of the global mesh
  vtkm::Id3 GlobalSize;
  // Index of the local blocks in x,y,z, i.e., in i,j,k mesh coordinates
  vtkm::cont::ArrayHandle<vtkm::Id3> LocalBlockIndices;
  // Origin of the local blocks in mesh index space
  vtkm::cont::ArrayHandle<vtkm::Id3> LocalBlockOrigins;
  // Size of each local block in x, y,z
  vtkm::cont::ArrayHandle<vtkm::Id3> LocalBlockSizes;
};


} // namespace contourtree_distributed
} // namespace worklet
} // namespace vtkm

#endif
