/*=========================================================================
 *
 *  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 "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkTestingMacros.h"


// Write a 2D SymmetricSecondRankTensor image to file and read it back again.
int
itkSymmetricSecondRankTensorImageWriteReadTest(int argc, char * argv[])
{
  if (argc < 1)
  {
    std::cerr << "Usage: " << itkNameOfTestExecutableMacro(argv) << " Input\n";
    return EXIT_FAILURE;
  }

  using TensorPixelType = itk::SymmetricSecondRankTensor<float, 2>;
  using TensorImageType = itk::Image<TensorPixelType, 2>;

  auto tensorImageInput = TensorImageType::New();

  auto size = TensorImageType::SizeType::Filled(10);

  const TensorImageType::RegionType region{ size };

  tensorImageInput->SetRegions(region);
  tensorImageInput->Allocate();

  TensorPixelType tensorPixelInput;

  tensorPixelInput(0, 0) = 1;
  tensorPixelInput(0, 1) = 2;
  tensorPixelInput(1, 1) = 3;

  itk::ImageRegionIterator<TensorImageType> itr(tensorImageInput, region);

  itr.GoToBegin();

  while (!itr.IsAtEnd())
  {
    itr.Set(tensorPixelInput);
    for (unsigned int i = 0; i < 3; ++i)
    {
      tensorPixelInput[i]++;
    }
    ++itr;
  }

  try
  {
    itk::WriteImage(tensorImageInput, argv[1]);
    const TensorImageType::ConstPointer tensorImageOutput = itk::ReadImage<TensorImageType>(argv[1]);

    // Compare the read values to the original values
    constexpr float tolerance{ 1e-5 };

    itk::ImageRegionConstIterator<TensorImageType> inIt(tensorImageInput, region);
    itk::ImageRegionConstIterator<TensorImageType> outIt(tensorImageOutput, region);

    inIt.GoToBegin();
    outIt.GoToBegin();

    while (!outIt.IsAtEnd())
    {
      tensorPixelInput = inIt.Get();
      const TensorPixelType tensorPixelOutput = outIt.Get();

      for (unsigned int i = 0; i < 3; ++i)
      {
        if (itk::Math::Absolute(tensorPixelInput[i] - tensorPixelOutput[i]) > tolerance)
        {
          std::cerr << "Tensor read does not match expected values " << std::endl;
          std::cerr << "Index " << inIt.ComputeIndex() << std::endl;
          std::cerr << "Tensor input value " << std::endl << tensorPixelInput << std::endl;
          std::cerr << "Tensor output value " << std::endl << tensorPixelOutput << std::endl;
          return EXIT_FAILURE;
        }
      }
      ++inIt;
      ++outIt;
    }
    return EXIT_SUCCESS;
  }
  catch (const itk::ExceptionObject & excp)
  {
    std::cerr << excp << std::endl;
    return EXIT_FAILURE;
  }
}
