/*=========================================================================
 *
 *  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 "itkMahalanobisDistanceThresholdImageFunction.h"
#include "itkImage.h"
#include "itkImageFunction.h"
#include "itkMath.h"
#include "itkTestingMacros.h"

int
itkMahalanobisDistanceThresholdImageFunctionTest(int, char *[])
{

  constexpr unsigned int Dimension{ 3 };
  using PixelComponentType = unsigned char;
  using PixelType = itk::RGBPixel<PixelComponentType>;

  using ImageType = itk::Image<PixelType, Dimension>;
  using FunctionType = itk::MahalanobisDistanceThresholdImageFunction<ImageType>;

  // Create and allocate the image
  auto                  image = ImageType::New();
  ImageType::SizeType   size{ 50, 50, 50 };
  ImageType::IndexType  start{};
  ImageType::RegionType region = { start, size };

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

  ImageType::PixelType initialValue;

  initialValue[0] = 11;
  initialValue[1] = 22;
  initialValue[2] = 33;

  image->FillBuffer(initialValue);

  auto function = FunctionType::New();

  ITK_EXERCISE_BASIC_OBJECT_METHODS(function, MahalanobisDistanceThresholdImageFunction, ImageFunction);

  function->SetInputImage(image);

  constexpr double threshold{ 5.0 };
  function->SetThreshold(threshold);

  FunctionType::CovarianceMatrixType covariance(Dimension, Dimension);
  FunctionType::MeanVectorType       mean(Dimension);

  mean[0] = 10.0;
  mean[1] = 20.0;
  mean[2] = 30.0;

  covariance.fill(0.0);
  covariance[0][0] = 100.0;
  covariance[1][1] = 200.0;
  covariance[2][2] = 300.0;

  function->SetCovariance(covariance);
  function->SetMean(mean);

  ITK_TEST_SET_GET_VALUE(covariance, function->GetCovariance());
  ITK_TEST_SET_GET_VALUE(mean, function->GetMean());

  ImageType::IndexType index;

  index[0] = 25;
  index[1] = 25;
  index[2] = 25;

  ITK_TEST_EXPECT_TRUE(function->EvaluateAtIndex(index));

  const double distance = function->EvaluateDistanceAtIndex(index);
  std::cout << "function->EvaluateDistanceAtIndex( index ): " << distance << std::endl;

  constexpr double expectedDistance{ 0.244949 };
  if (!itk::Math::FloatAlmostEqual(distance, expectedDistance, 10, 1e-5))
  {
    std::cerr << "Error in distance computation in EvaluateDistanceAtIndex() !!" << std::endl;
    std::cerr << "Expected distance value = " << expectedDistance << std::endl;
    std::cerr << "Distance obtained value = " << distance << std::endl;
    return EXIT_FAILURE;
  }

  // Test Evaluate
  FunctionType::PointType point;
  point[0] = 25;
  point[1] = 25;
  point[2] = 25;

  ITK_TEST_EXPECT_TRUE(function->Evaluate(point));

  const double distance2 = function->EvaluateDistance(point);
  std::cout << "function->EvaluateDistance(point): " << distance2 << std::endl;

  if (!itk::Math::FloatAlmostEqual(distance2, expectedDistance, 10, 1e-5))
  {
    std::cerr << "Error in distance computation in EvaluateDistance() !!" << std::endl;
    std::cerr << "Expected distance value = " << expectedDistance << std::endl;
    std::cerr << "Distance obtained value = " << distance2 << std::endl;
    return EXIT_FAILURE;
  }

  // Test EvaluateAtContinuousIndex
  FunctionType::ContinuousIndexType cindex;
  cindex[0] = 25;
  cindex[1] = 25;
  cindex[2] = 25;

  ITK_TEST_EXPECT_TRUE(function->EvaluateAtContinuousIndex(cindex));

  // Test GetConstReferenceMacro
  const double & getThreshold = function->GetThreshold();
  std::cout << "function->GetThreshold(): " << getThreshold << std::endl;
  if (!itk::Math::FloatAlmostEqual(threshold, getThreshold, 10, 1e-9))
  {
    std::cerr << "Error: Set/Get Threshold do not match" << std::endl;
    return EXIT_FAILURE;
  }

  std::cout << "Test PASSED ! " << std::endl;
  return EXIT_SUCCESS;
}
