/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/

#ifndef itkWhitakerSparseLevelSetImage_hxx
#define itkWhitakerSparseLevelSetImage_hxx


namespace itk
{

template <typename TOutput, unsigned int VDimension>
WhitakerSparseLevelSetImage<TOutput, VDimension>::WhitakerSparseLevelSetImage()
{
  this->InitializeLayers();
  this->InitializeInternalLabelList();
}

template <typename TOutput, unsigned int VDimension>
auto
WhitakerSparseLevelSetImage<TOutput, VDimension>::Evaluate(const InputType & inputIndex) const -> OutputType
{
  InputType mapIndex = inputIndex - this->m_DomainOffset;
  auto      layerIt = this->m_Layers.begin();

  auto rval = static_cast<OutputType>(ZeroLayer());

  while (layerIt != this->m_Layers.end())
  {
    auto it = (layerIt->second).find(mapIndex);
    if (it != (layerIt->second).end())
    {
      rval = it->second;
      break;
    }

    ++layerIt;
  }
  // if layer not found, look using label map
  if (layerIt == this->m_Layers.end())
  {
    if (this->m_LabelMap.IsNotNull())
    {
      if (this->m_LabelMap->GetLabelObject(MinusThreeLayer())->HasIndex(mapIndex))
      {
        rval = static_cast<OutputType>(MinusThreeLayer());
      }
      else
      {
        char status = this->m_LabelMap->GetPixel(mapIndex);
        if (status == this->PlusThreeLayer())
        {
          rval = static_cast<OutputType>(this->PlusThreeLayer());
        }
        else
        {
          itkGenericExceptionMacro("status " << static_cast<int>(status) << " should be 3 or -3");
        }
      }
    }
    else
    {
      itkGenericExceptionMacro("Note: m_LabelMap is nullptr");
    }
  }
  return rval;
}


template <typename TOutput, unsigned int VDimension>
void
WhitakerSparseLevelSetImage<TOutput, VDimension>::InitializeLayers()
{
  this->m_Layers.clear();
  this->m_Layers[MinusTwoLayer()] = LayerType();
  this->m_Layers[MinusOneLayer()] = LayerType();
  this->m_Layers[ZeroLayer()] = LayerType();
  this->m_Layers[PlusOneLayer()] = LayerType();
  this->m_Layers[PlusTwoLayer()] = LayerType();
}


template <typename TOutput, unsigned int VDimension>
void
WhitakerSparseLevelSetImage<TOutput, VDimension>::InitializeInternalLabelList()
{
  this->m_InternalLabelList.clear();
  this->m_InternalLabelList.push_back(MinusThreeLayer());
  this->m_InternalLabelList.push_back(MinusTwoLayer());
  this->m_InternalLabelList.push_back(MinusOneLayer());
  this->m_InternalLabelList.push_back(ZeroLayer());
}
} // namespace itk

#endif // itkWhitakerSparseLevelSetImage_hxx
