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

/**
 *
 *  This program illustrates the AdaptImageFilter
 *
 *  The example shows how an Accessor can be used to
 *  convert an Vector image to an image that has
 *  just a single component.
 *
 *  That will allow to pass a component of the
 *  image as input any filter that expects
 *  a float image
 *
 */


#include "itkAdaptImageFilter.h"
#include "itkNthElementPixelAccessor.h"

#include "vnl/vnl_sample.h"
#include "itkMath.h"


//-------------------------------------
//     Typedefs for convenience
//-------------------------------------
using myVectorImageType = itk::Image<itk::Vector<float, 3>, 2>;
using myVectorIteratorType = itk::ImageRegionIteratorWithIndex<myVectorImageType>;

using myAccessorType = itk::NthElementPixelAccessor<float, itk::Vector<float, 3>>;

using myImageType = itk::Image<float, 2>;
using myIteratorType = itk::ImageRegionIteratorWithIndex<myImageType>;

//-------------------------
//
//   Main code
//
//-------------------------
int
itkAdaptImageFilterTest2(int, char *[])
{


  myVectorImageType::SizeType size;
  size[0] = 2;
  size[1] = 2;

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

  myVectorImageType::RegionType region;
  region.SetIndex(index);
  region.SetSize(size);

  auto myImage = myVectorImageType::New();


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

  myVectorIteratorType it1(myImage, myImage->GetRequestedRegion());

  // Value to initialize the pixels
  myVectorImageType::PixelType color;

  // Initializing all the pixel in the image
  it1.GoToBegin();
  while (!it1.IsAtEnd())
  {
    color[0] = static_cast<float>(vnl_sample_uniform(0.0, 1.0));
    color[1] = static_cast<float>(vnl_sample_uniform(0.0, 1.0));
    color[2] = static_cast<float>(vnl_sample_uniform(0.0, 1.0));
    it1.Set(color);
    ++it1;
  }

  // Reading the values to verify the image content
  std::cout << "--- Initial image --- " << std::endl;
  it1.GoToBegin();
  while (!it1.IsAtEnd())
  {
    const myVectorImageType::PixelType c(it1.Get());
    std::cout << c[0] << "  ";
    std::cout << c[1] << "  ";
    std::cout << c[2] << std::endl;
    ++it1;
  }


  bool passed = true;

  // Get the first element
  using AdaptFilterType = itk::AdaptImageFilter<myVectorImageType, myImageType, myAccessorType>;

  auto adaptImage = AdaptFilterType::New();

  myAccessorType accessor;
  accessor.SetElementNumber(0);

  adaptImage->SetAccessor(accessor);
  adaptImage->SetInput(myImage);
  adaptImage->UpdateLargestPossibleRegion();

  myIteratorType it(adaptImage->GetOutput(), adaptImage->GetOutput()->GetRequestedRegion());

  std::cout << "--- First component values --- " << std::endl;

  it.GoToBegin();
  it1.GoToBegin();
  while (!it.IsAtEnd())
  {
    std::cout << it.Get() << std::endl;
    if (itk::Math::NotExactlyEquals(it.Get(), it1.Get()[0]))
    {
      passed = false;
    }

    ++it;
    ++it1;
  }

  // Get the second element
  accessor.SetElementNumber(1);
  adaptImage->SetAccessor(accessor);
  adaptImage->UpdateLargestPossibleRegion();

  it = myIteratorType(adaptImage->GetOutput(), adaptImage->GetOutput()->GetRequestedRegion());

  std::cout << "--- Second component values --- " << std::endl;

  it.GoToBegin();
  it1.GoToBegin();
  while (!it.IsAtEnd())
  {
    std::cout << it.Get() << std::endl;
    if (itk::Math::NotExactlyEquals(it.Get(), it1.Get()[1]))
    {
      passed = false;
    }

    ++it;
    ++it1;
  }

  // Convert to the third component
  accessor.SetElementNumber(2);
  adaptImage->SetAccessor(accessor);
  adaptImage->UpdateLargestPossibleRegion();

  it = myIteratorType(adaptImage->GetOutput(), adaptImage->GetOutput()->GetRequestedRegion());

  std::cout << "--- Third component values --- " << std::endl;

  it.GoToBegin();
  it1.GoToBegin();
  while (!it.IsAtEnd())
  {
    std::cout << it.Get() << std::endl;
    if (itk::Math::NotExactlyEquals(it.Get(), it1.Get()[2]))
    {
      passed = false;
    }

    ++it;
    ++it1;
  }

  // Test access to Accessor
  std::cout << adaptImage->GetAccessor().GetElementNumber() << std::endl;

  std::cout << std::endl;
  if (passed)
  {
    std::cout << "AdaptImageFilterTest2 passed" << std::endl;
    return EXIT_SUCCESS;
  }
  else
  {
    std::cout << "AdaptImageFilterTest2 passed" << std::endl;
    return EXIT_FAILURE;
  }
}
