/*=========================================================================
 *
 *  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 <fstream>

#include "itkPointSetToListSampleAdaptor.h"

#include "itkGaussianMixtureModelComponent.h"

int
itkGaussianMixtureModelComponentTest(int argc, char * argv[])
{
  using PointSetType = itk::PointSet<double, 2>;
  using DataSampleType = itk::Statistics::PointSetToListSampleAdaptor<PointSetType>;
  using ComponentType = itk::Statistics::GaussianMixtureModelComponent<DataSampleType>;

  if (argc < 2)
  {
    std::cout << "ERROR: data file name argument missing." << std::endl;
    return EXIT_FAILURE;
  }

  char * dataFileName = argv[1];
  int    dataSize = 2000;
  using ParametersType = itk::Array<double>;
  unsigned int numberOfClasses = 2;

  ParametersType params(6);

  std::vector<ParametersType> initialParameters(numberOfClasses);
  params[0] = 80.0;
  params[1] = 80.0;
  params[2] = 814.95741;
  params[3] = 38.40308;
  params[4] = 38.40308;
  params[5] = 817.64446;
  initialParameters[0] = params;

  params[0] = 180.0;
  params[1] = 180.0;
  params[2] = 859.785295;
  params[3] = -3.617316;
  params[4] = -3.617316;
  params[5] = 848.991508;
  initialParameters[1] = params;

  itk::Array<double> trueProportions(numberOfClasses);
  trueProportions[0] = 0.5;
  trueProportions[1] = 0.5;

  itk::Array<double> initialProportions(numberOfClasses);
  initialProportions[0] = 0.5;
  initialProportions[1] = 0.5;

  /* Loading point data */
  auto                                 pointSet = PointSetType::New();
  PointSetType::PointsContainerPointer pointsContainer = PointSetType::PointsContainer::New();
  pointsContainer->Reserve(dataSize);
  pointSet->SetPoints(pointsContainer);

  PointSetType::PointsContainerIterator p_iter = pointsContainer->Begin();
  PointSetType::PointType               point;
  double                                temp;
  std::ifstream                         dataStream(dataFileName);
  if (!dataStream)
  {
    std::cout << "ERROR: fail to open the data file." << std::endl;
    return EXIT_FAILURE;
  }

  while (p_iter != pointsContainer->End())
  {
    for (unsigned int i = 0; i < PointSetType::PointDimension; ++i)
    {
      dataStream >> temp;
      point[i] = temp;
    }
    p_iter.Value() = point;
    ++p_iter;
  }

  dataStream.close();

  /* Importing the point set to the sample */
  auto sample = DataSampleType::New();

  sample->SetPointSet(pointSet);

  /* Preparing the gaussian mixture components */
  using ComponentPointer = ComponentType::Pointer;
  std::vector<ComponentPointer> components;
  for (unsigned int i = 0; i < numberOfClasses; ++i)
  {
    components.push_back(ComponentType::New());
    (components[i])->SetSample(sample);
    (components[i])->SetParameters(initialParameters[i]);
  }

  ComponentPointer testComponent = ComponentType::New();

  std::cout << testComponent->GetNameOfClass() << std::endl;
  testComponent->Print(std::cout);

  std::cout << "Test passed." << std::endl;
  return EXIT_SUCCESS;
}