/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkmTriangleMeshPointNormals.cxx

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm 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.

=========================================================================*/
#include "vtkmTriangleMeshPointNormals.h"

#include "vtkCellArray.h"
#include "vtkCellData.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkPointData.h"
#include "vtkPolyData.h"
#include "vtkSmartPointer.h"

#include "vtkmlib/ArrayConverters.h"
#include "vtkmlib/PolyDataConverter.h"
#include "vtkmlib/Storage.h"

#include "vtkmCellSetExplicit.h"
#include "vtkmCellSetSingleType.h"
#include "vtkmFilterPolicy.h"

#include "vtkm/filter/SurfaceNormals.h"


namespace {

struct InputFilterPolicy : public vtkmInputFilterPolicy
{
  using UnstructuredCellSetList =
    vtkm::ListTagBase<vtkm::cont::vtkmCellSetSingleType>;
};

}

vtkStandardNewMacro(vtkmTriangleMeshPointNormals)

//------------------------------------------------------------------------------
void vtkmTriangleMeshPointNormals::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
}

//------------------------------------------------------------------------------
vtkmTriangleMeshPointNormals::vtkmTriangleMeshPointNormals() = default;
vtkmTriangleMeshPointNormals::~vtkmTriangleMeshPointNormals() = default;

//------------------------------------------------------------------------------
int vtkmTriangleMeshPointNormals::RequestData(
  vtkInformation *request,
  vtkInformationVector **inputVector,
  vtkInformationVector *outputVector)
{
  // get the info objects
  vtkInformation *inInfo = inputVector[0]->GetInformationObject(0);
  vtkInformation *outInfo = outputVector->GetInformationObject(0);

  // get the input and output
  vtkPolyData *input = vtkPolyData::SafeDownCast(
    inInfo->Get(vtkDataObject::DATA_OBJECT()));
  vtkPolyData *output = vtkPolyData::SafeDownCast(
    outInfo->Get(vtkDataObject::DATA_OBJECT()));

  // check if polydata is in supported format
  if (input->GetVerts()->GetNumberOfCells() != 0 ||
      input->GetLines()->GetNumberOfCells() != 0 ||
      input->GetStrips()->GetNumberOfCells() != 0 ||
      (input->GetPolys()->GetNumberOfConnectivityEntries() % 4) != 0)
  {
    vtkErrorMacro(<< "This filter only works with polydata containing just triangles.");
    return 0;
  }

  // convert the input dataset to a vtkm::cont::DataSet
  vtkm::cont::DataSet in = tovtkm::Convert(input);
  if (in.GetNumberOfCoordinateSystems() <= 0 || in.GetNumberOfCellSets() <= 0)
  {
    vtkErrorMacro(<< "Could not convert vtk dataset to vtkm dataset");
    return 0;
  }

  vtkm::filter::PolicyBase<InputFilterPolicy> policy;

  vtkm::filter::SurfaceNormals filter;
  filter.SetGenerateCellNormals(false);
  filter.SetNormalizeCellNormals(false);
  filter.SetGeneratePointNormals(true);
  filter.SetPointNormalsName("Normals");
  auto result = filter.Execute(in, policy);

  if (!result.IsFieldValid())
  {
    vtkWarningMacro(<< "VTKm SurfaceNormals algorithm failed to run."
                    << "Falling back to vtkTriangleMeshPointNormals.");
    return this->Superclass::RequestData(request, inputVector, outputVector);
  }

  if (!fromvtkm::Convert(result.GetDataSet(), output, input))
  {
    vtkErrorMacro(<< "Unable to convert VTKm DataSet back to VTK");
    return 0;
  }
  vtkSmartPointer<vtkDataArray> pointNormals = output->GetPointData()->GetArray("Normals");

  output->GetPointData()->CopyNormalsOff();
  output->GetPointData()->PassData(input->GetPointData());
  output->GetCellData()->CopyNormalsOff();
  output->GetCellData()->PassData(input->GetPointData());

  if (pointNormals)
  {
    output->GetPointData()->SetNormals(pointNormals);
  }

  return 1;
}