/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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
 *
 *         http://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 "itkGaussianImageSource.h"
#include "itkLinearInterpolateImageFunction.h"
#include "itkMeanSquaresHistogramImageToImageMetric.h"
#include "itkTranslationTransform.h"
#include "itkMath.h"

int itkHistogramImageToImageMetricTest(int , char*[] )
{
  // Create two simple images.
  const unsigned int ImageDimension = 2;
  typedef double PixelType;
  typedef double CoordinateRepresentationType;

  //Allocate Images
  typedef itk::Image<PixelType,ImageDimension> MovingImageType;
  typedef itk::Image<PixelType,ImageDimension> FixedImageType;

  // Declare Gaussian Sources
  typedef itk::GaussianImageSource<MovingImageType> MovingImageSourceType;
  typedef itk::GaussianImageSource<FixedImageType>  FixedImageSourceType;

  // Note: the following declarations are classical arrays
  FixedImageType::SizeValueType fixedImageSize[] = {100,  100};
  MovingImageType::SizeValueType movingImageSize[] = {100,  100};

  FixedImageType::SpacingValueType fixedImageSpacing[]  = {1.0f, 1.0f};
  MovingImageType::SpacingValueType movingImageSpacing[] = {1.0f, 1.0f};

  FixedImageType::PointValueType fixedImageOrigin[] = {0.0f, 0.0f};
  MovingImageType::PointValueType movingImageOrigin[] = {0.0f, 0.0f};

  MovingImageSourceType::Pointer movingImageSource =
    MovingImageSourceType::New();
  FixedImageSourceType::Pointer  fixedImageSource  =
    FixedImageSourceType::New();

  movingImageSource->SetSize(movingImageSize);
  movingImageSource->SetOrigin(movingImageOrigin);
  movingImageSource->SetSpacing(movingImageSpacing);
  movingImageSource->SetNormalized(false);
  movingImageSource->SetScale(250.0f);

  fixedImageSource->SetSize(fixedImageSize);
  fixedImageSource->SetOrigin(fixedImageOrigin);
  fixedImageSource->SetSpacing(fixedImageSpacing);
  fixedImageSource->SetNormalized(false);
  fixedImageSource->SetScale(250.0f);

  movingImageSource->Update(); // Force the filter to run
  fixedImageSource->Update();  // Force the filter to run

  MovingImageType::Pointer movingImage = movingImageSource->GetOutput();
  FixedImageType::Pointer  fixedImage  = fixedImageSource->GetOutput();

  // Set up the metric.
  typedef itk::MeanSquaresHistogramImageToImageMetric<FixedImageType,
    MovingImageType>                        MetricType;
  typedef MetricType::TransformType         TransformBaseType;
  typedef MetricType::ScalesType            ScalesType;
  typedef MetricType::DerivativeType        DerivativeType;
  typedef TransformBaseType::ParametersType ParametersType;

  MetricType::Pointer metric = MetricType::New();

  unsigned int nBins = 256;
  MetricType::HistogramType::SizeType histSize;
  histSize.SetSize(2);
  histSize[0] = nBins;
  histSize[1] = nBins;
  metric->SetHistogramSize(histSize);

  // Plug the images into the metric.
  metric->SetFixedImage(fixedImage);
  metric->SetMovingImage(movingImage);

  // Set up a transform.
  typedef itk::TranslationTransform<CoordinateRepresentationType,
    ImageDimension> TransformType;

  TransformType::Pointer transform = TransformType::New();
  metric->SetTransform(transform.GetPointer());

  // Set up an interpolator.
  typedef itk::LinearInterpolateImageFunction<MovingImageType,
    double> InterpolatorType;

  InterpolatorType::Pointer interpolator = InterpolatorType::New();
  interpolator->SetInputImage(movingImage.GetPointer());
  metric->SetInterpolator(interpolator.GetPointer());

  // Define the region over which the metric will be computed.
  metric->SetFixedImageRegion(fixedImage->GetBufferedRegion());

  // Set up transform parameters.
  const unsigned int numberOfParameters = transform->GetNumberOfParameters();

  ParametersType parameters( numberOfParameters );
  for (unsigned int k = 0; k < numberOfParameters; k++)
    {
    parameters[k] = 0.0;
    }

  // Set scales for derivative calculation.
  ScalesType scales( numberOfParameters );
  for (unsigned int k = 0; k < numberOfParameters; k++)
    {
    scales[k] = 1;
    }

  const double STEP_LENGTH = 0.001;
  metric->SetDerivativeStepLength(STEP_LENGTH);
  metric->SetDerivativeStepLengthScales(scales);

  try
    {
    // Initialize the metric.
    metric->Initialize();

    // Test SetPaddingValue() and GetPaddingValue().
    metric->SetPaddingValue(-1);
    metric->SetUsePaddingValue(true);

    if (itk::Math::NotExactlyEquals(metric->GetPaddingValue(), -1))
      {
      std::cerr << "Incorrect padding value." << std::endl;
      return EXIT_FAILURE;
      }

    // Check to make sure the returned histogram size is the same as histSize.
    if (histSize != metric->GetHistogramSize())
      {
      std::cout << "Incorrect histogram size." << std::endl;
      return EXIT_FAILURE;
      }

    // Check GetDerivativeStepLength().
    if (itk::Math::NotExactlyEquals(metric->GetDerivativeStepLength(), STEP_LENGTH))
      {
      std::cout << "Incorrect derivative step length." << std::endl;
      return EXIT_FAILURE;
      }

    // Check GetDerivativeStepLengthScales().
    if (metric->GetDerivativeStepLengthScales() != scales)
      {
      std::cout << "Incorrect scales." << std::endl;
      return EXIT_FAILURE;
      }

    // Do some work
    DerivativeType derivatives( numberOfParameters );
    MetricType::MeasureType value;
    for (double y = -50.0; y <= 50.0; y += 25.0)
      {
      parameters[1] = y;
      for (double x = -50.0; x <= 50.0; x += 25.0)
        {
        parameters[0] = x;
        metric->GetValueAndDerivative (parameters, value, derivatives);
        std::cout << "Parameters: " << parameters
                  << ", Value: " << value
                  << ", Derivatives: " << derivatives << std::endl;
        }
      }

    // Exercise Print() method.
    metric->Print(std::cout);

    std::cout << "Test passed." << std::endl;
    }
  catch (itk::ExceptionObject& ex)
    {
    std::cerr << "Exception caught!" << std::endl;
    std::cerr << ex << std::endl;
    return EXIT_FAILURE;
    }


  std::cout << "Exercise the SetLowerBound() and SetUpperBound() methods " << std::endl;

  MetricType::MeasurementVectorType lowerBound;
  lowerBound.Fill(0.0);
  MetricType::MeasurementVectorType upperBound;
  upperBound.Fill(0.0);

  metric->SetLowerBound( lowerBound );
  metric->SetUpperBound( upperBound );

  try
    {
    // Initialize the metric.
    metric->Initialize();

    // Exercise Print() method.
    metric->Print(std::cout);

    std::cout << "Test passed." << std::endl;
    }
  catch (itk::ExceptionObject& ex)
    {
    std::cerr << "Exception caught!" << std::endl;
    std::cerr << ex << std::endl;
    return EXIT_FAILURE;
    }

  // Force an exception
  try
    {
    ParametersType parameters2( 2 );
    DerivativeType derivatives2( 2 );
    ScalesType badScales( 1 );
    metric->SetDerivativeStepLengthScales(badScales);
    metric->Initialize();
    metric->GetDerivative (parameters2, derivatives2);
    }
  catch (itk::ExceptionObject &ex)
    {
    std::cerr << "Expected exception caught!" << std::endl;
    std::cerr << ex << std::endl;
    return EXIT_SUCCESS;
    }
  return EXIT_FAILURE;
}