/*=========================================================================
 *
 *  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.
 *
 *=========================================================================*/

#include "itkLevelSetContainer.h"
#include "itkLevelSetEquationChanAndVeseInternalTerm.h"
#include "itkLevelSetEquationTermContainer.h"
#include "itkAtanRegularizedHeavisideStepFunction.h"

int
itkMultiLevelSetChanAndVeseInternalTermTest(int, char *[])
{
  constexpr unsigned int Dimension = 2;

  using InputPixelType = unsigned char;
  using InputImageType = itk::Image<InputPixelType, Dimension>;
  using InputIteratorType = itk::ImageRegionIteratorWithIndex<InputImageType>;

  using PixelType = float;
  using ImageType = itk::Image<PixelType, Dimension>;
  using LevelSetType = itk::LevelSetDenseImage<ImageType>;
  using LevelSetOutputRealType = LevelSetType::OutputRealType;

  using IteratorType = itk::ImageRegionIteratorWithIndex<ImageType>;
  using IdentifierType = itk::IdentifierType;
  using IdListType = std::list<IdentifierType>;
  using IdListImageType = itk::Image<IdListType, Dimension>;
  using CacheImageType = itk::Image<short, Dimension>;
  using DomainMapImageFilterType = itk::LevelSetDomainMapImageFilter<IdListImageType, CacheImageType>;

  using LevelSetContainerType = itk::LevelSetContainer<IdentifierType, LevelSetType>;
  using ChanAndVeseTermType = itk::LevelSetEquationChanAndVeseInternalTerm<InputImageType, LevelSetContainerType>;
  using TermContainerType = itk::LevelSetEquationTermContainer<InputImageType, LevelSetContainerType>;

  using HeavisideFunctionBaseType =
    itk::AtanRegularizedHeavisideStepFunction<LevelSetOutputRealType, LevelSetOutputRealType>;

  ImageType::IndexType index;
  index[0] = 0;
  index[1] = 0;

  ImageType::SizeType size;
  size[0] = 10;
  size[1] = 10;

  ImageType::RegionType region{ index, size };

  PixelType value = 0.;

  auto input = InputImageType::New();
  input->SetRegions(region);
  input->Allocate();
  input->FillBuffer(0);

  InputIteratorType it(input, input->GetLargestPossibleRegion());
  it.GoToBegin();
  while (!it.IsAtEnd())
  {
    it.Set(1);
    ++it;
  }

  auto input1 = ImageType::New();
  input1->SetRegions(region);
  input1->Allocate();
  input1->FillBuffer(value);

  auto input2 = ImageType::New();
  input2->SetRegions(region);
  input2->Allocate();
  input2->FillBuffer(value);

  ImageType::IndexType idx;
  IdListType           list_ids;

  auto id_image = IdListImageType::New();
  id_image->SetRegions(region);
  id_image->Allocate();
  id_image->FillBuffer(list_ids);

  // Define the Heaviside function
  auto heaviside = HeavisideFunctionBaseType::New();
  heaviside->SetEpsilon(1.0);

  auto domainMapFilter = DomainMapImageFilterType::New();
  domainMapFilter->SetInput(id_image);
  domainMapFilter->Update();
  CacheImageType::Pointer output = domainMapFilter->GetOutput();
  std::cout << "Domain partition computed" << std::endl;

  IteratorType it1(input1, input1->GetLargestPossibleRegion());
  IteratorType it2(input2, input2->GetLargestPossibleRegion());
  it1.GoToBegin();
  it2.GoToBegin();

  while (!it1.IsAtEnd())
  {
    idx = it1.GetIndex();
    list_ids.clear();

    if ((idx[0] < 5) && (idx[1] < 5))
    {
      list_ids.push_back(1);
    }

    if ((idx[0] > 1) && (idx[1] > 1) && (idx[0] < 8) && (idx[1] < 8))
    {
      list_ids.push_back(2);
    }

    id_image->SetPixel(idx, list_ids);

    it1.Set(std::sqrt(static_cast<float>((idx[0] - 2) * (idx[0] - 2) + (idx[1] - 2) * (idx[1] - 2))));

    it2.Set(std::sqrt(static_cast<float>((idx[0] - 5) * (idx[0] - 5) + (idx[1] - 5) * (idx[1] - 5))));
    ++it1;
    ++it2;
  }

  // Map of levelset bases
  std::map<itk::IdentifierType, LevelSetType::Pointer> level_set;
  level_set[1] = LevelSetType::New();
  level_set[1]->SetImage(input1);

  level_set[2] = LevelSetType::New();
  level_set[2]->SetImage(input2);

  // Insert the levelsets in a levelset container
  bool levelSetNotYetAdded;
  auto lscontainer = LevelSetContainerType::New();
  lscontainer->SetHeaviside(heaviside);
  lscontainer->SetDomainMapFilter(domainMapFilter);

  levelSetNotYetAdded = lscontainer->AddLevelSet(0, level_set[1], false);
  if (!levelSetNotYetAdded)
  {
    return EXIT_FAILURE;
  }
  levelSetNotYetAdded = lscontainer->AddLevelSet(1, level_set[2], false);
  if (!levelSetNotYetAdded)
  {
    return EXIT_FAILURE;
  }
  std::cout << "Level set container created" << std::endl;

  // Create ChanAndVeseTerm
  auto cvTerm = ChanAndVeseTermType::New();
  cvTerm->SetInput(input);
  cvTerm->SetCoefficient(1.0);
  cvTerm->SetCurrentLevelSetId(0);
  cvTerm->SetLevelSetContainer(lscontainer);
  std::cout << "CV term created" << std::endl;

  // Create Term Container
  auto termContainer = TermContainerType::New();
  termContainer->AddTerm(0, cvTerm);
  std::cout << "Term container created" << std::endl;

  using DomainMapType = DomainMapImageFilterType::DomainMapType;
  const DomainMapType domainMap = domainMapFilter->GetDomainMap();
  auto                map_it = domainMap.begin();
  auto                map_end = domainMap.end();

  LevelSetType::Pointer        levelSet;
  ChanAndVeseTermType::Pointer eqTerm;
  while (map_it != map_end)
  {
    const IdListImageType::RegionType temp_region = *(map_it->second.GetRegion());

    itk::ImageRegionConstIteratorWithIndex<IdListImageType> temp_it(id_image, temp_region);
    temp_it.GoToBegin();

    while (!temp_it.IsAtEnd())
    {
      std::cout << temp_it.GetIndex() << std::endl;
      const IdListType * lout = map_it->second.GetIdList();

      if (lout->empty())
      {
        return EXIT_FAILURE;
      }

      for (const auto & lIt : *lout)
      {
        std::cout << lIt << ' ';
        levelSet = lscontainer->GetLevelSet(lIt - 1);
        std::cout << levelSet->Evaluate(temp_it.GetIndex()) << std::endl;

        if (lIt - 1 == 0)
        {
          eqTerm = dynamic_cast<ChanAndVeseTermType *>(termContainer->GetTerm(lIt - 1));
          std::cout << eqTerm->Evaluate(temp_it.GetIndex()) << std::endl;
        }
      }
      std::cout << std::endl;
      ++temp_it;
    }
    ++map_it;
  }

  return EXIT_SUCCESS;
}