/*=========================================================================
 *
 *  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 "itkMultiResolutionPDEDeformableRegistration.h"
#include "itkWarpImageFilter.h"
#include "itkNearestNeighborInterpolateImageFunction.h"

#include "itkImageFileWriter.h"

#include <iostream>

namespace
{

// The following class is used to support callbacks
// on the filter in the pipeline that follows later
class ShowProgressPDEObject
{
public:
  ShowProgressPDEObject(itk::ProcessObject* o) :
    m_Process(o),
    m_Prefix("")
    {
    }
  void ShowProgress()
    {
    std::cout <<  m_Prefix;
    std::cout << "Progress " << m_Process->GetProgress() << std::endl;
    }
  void ShowIteration()
    {
    std::cout << "Level Completed" << std::endl;
    }
  itk::ProcessObject::Pointer m_Process;
  std::string                 m_Prefix;
};

template<typename TRegistration>
class PDERegistrationController
{
public:
  PDERegistrationController(TRegistration* o)
    {m_Process = o;}
  void ShowProgress()
    {
    if ( m_Process->GetCurrentLevel() == 3 )
      { m_Process->StopRegistration(); }
    }
  typename TRegistration::Pointer m_Process;
};

}


// Template function to fill in an image with a value
template <typename TImage>
void
FillImage(
TImage * image,
typename TImage::PixelType value )
{

  typedef itk::ImageRegionIteratorWithIndex<TImage> Iterator;
  Iterator it( image, image->GetBufferedRegion() );
  it.GoToBegin();

  while( !it.IsAtEnd() )
    {
    it.Set( value );
    ++it;
    }

}


// Template function to fill in an image with a circle.
template <typename TImage>
void
FillWithCircle(
TImage * image,
double * center,
double radius,
typename TImage::PixelType foregnd,
typename TImage::PixelType backgnd )
{

 typedef itk::ImageRegionIteratorWithIndex<TImage> Iterator;
 Iterator it( image, image->GetBufferedRegion() );
 it.GoToBegin();

 typename TImage::IndexType index;
 double r2 = itk::Math::sqr( radius );

 while( !it.IsAtEnd() )
  {
    index = it.GetIndex();
    double distance = 0;
    for( unsigned int j = 0; j < TImage::ImageDimension; j++ )
      {
      distance += itk::Math::sqr((double) index[j] - center[j]);
      }
    if( distance <= r2 ) it.Set( foregnd );
    else it.Set( backgnd );
    ++it;
  }

}


// Template function to copy image regions
template <typename TImage>
void
CopyImageBuffer(
TImage *input,
TImage *output )
{
  typedef itk::ImageRegionIteratorWithIndex<TImage> Iterator;
  Iterator outIt( output, output->GetBufferedRegion() );
  for( Iterator inIt( input, output->GetBufferedRegion() ); !inIt.IsAtEnd(); ++inIt, ++outIt )
    {
    outIt.Set( inIt.Get() );
    }

}

int itkMultiResolutionPDEDeformableRegistrationTest(int argc, char* argv[] )
{

  typedef unsigned char PixelType;
  enum {ImageDimension = 2};
  typedef itk::Image<PixelType,ImageDimension>  ImageType;
  typedef itk::Vector<float,ImageDimension>     VectorType;
  typedef itk::Image<VectorType,ImageDimension> FieldType;
  typedef ImageType::IndexType                  IndexType;
  typedef ImageType::SizeType                   SizeType;
  typedef ImageType::RegionType                 RegionType;

  if(argc < 2)
    {
    std::cerr << "Usage: " << argv[0] << " WarpedImage\n";
    return -1;
    }

  //--------------------------------------------------------
  std::cout << "Generate input images and initial field";
  std::cout << std::endl;

  SizeType size;
  size.Fill( 256 );
  size[1] = 251;

  IndexType index;
  index.Fill( 0 );
  index[0] = 3;

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

  ImageType::PointType origin;
  origin.Fill( 0.0 );
  origin[0] = 0.8;

  ImageType::SpacingType spacing;
  spacing.Fill( 1.0 );
  spacing[1] = 1.2;

  ImageType::Pointer moving = ImageType::New();
  ImageType::Pointer fixed = ImageType::New();
  FieldType::Pointer initField = FieldType::New();

  moving->SetLargestPossibleRegion( region );
  moving->SetBufferedRegion( region );
  moving->Allocate();
  moving->SetOrigin( origin );
  moving->SetSpacing( spacing );

  fixed->SetLargestPossibleRegion( region );
  fixed->SetBufferedRegion( region );
  fixed->Allocate();
  fixed->SetOrigin( origin );
  fixed->SetSpacing( spacing );

  initField->SetLargestPossibleRegion( region );
  initField->SetBufferedRegion( region );
  initField->Allocate();
  initField->SetOrigin( origin );
  initField->SetSpacing( spacing );

  double center[ImageDimension];
  double radius;
  PixelType fgnd = 250;
  PixelType bgnd = 15;

  // fill moving with circle
  center[0] = 128; center[1] = 128; radius = 60;
  FillWithCircle<ImageType>( moving, center, radius, fgnd, bgnd );

  // fill fixed with circle
  center[0] = 115; center[1] = 120; radius = 65;
  FillWithCircle<ImageType>( fixed, center, radius, fgnd, bgnd );

  // fill initial deformation with zero vectors
  VectorType zeroVec;
  zeroVec.Fill( 0.0 );
  FillImage<FieldType>( initField, zeroVec );

  //----------------------------------------------------------------
  std::cout << "Run registration." << std::endl;

  typedef itk::MultiResolutionPDEDeformableRegistration<ImageType,
    ImageType, FieldType> RegistrationType;

  RegistrationType::Pointer registrator = RegistrationType::New();

  registrator->SetMovingImage( moving );
  registrator->SetFixedImage( fixed );
  registrator->GetModifiableFixedImagePyramid()->UseShrinkImageFilterOn();
  registrator->GetModifiableMovingImagePyramid()->UseShrinkImageFilterOn();

  unsigned int numLevel = 3;
  unsigned int numIterations[10];
  numIterations[0] = 64;

  unsigned int ilevel;
  for( ilevel = 1; ilevel < numLevel; ilevel++ )
    {
    numIterations[ilevel] = numIterations[ilevel-1]/2;
    }

  registrator->SetNumberOfLevels( numLevel );
  registrator->SetNumberOfIterations( numIterations );

  registrator->Print(std::cout);

  typedef itk::SimpleMemberCommand<ShowProgressPDEObject> CommandType;

  ShowProgressPDEObject progressWatch(registrator);
  CommandType::Pointer command = CommandType::New();
  command->SetCallbackFunction(&progressWatch,
                               &ShowProgressPDEObject::ShowIteration);
  registrator->AddObserver(itk::IterationEvent(), command );

  PDERegistrationController<RegistrationType> controller(registrator);
  typedef itk::SimpleMemberCommand< PDERegistrationController<RegistrationType> >
    ControllerType;
  ControllerType::Pointer controllerCommand = ControllerType::New();
  controllerCommand->SetCallbackFunction(
    &controller, &PDERegistrationController<RegistrationType>::ShowProgress );
  registrator->AddObserver(itk::ProgressEvent(), controllerCommand );

  ShowProgressPDEObject innerWatch(registrator->GetModifiableRegistrationFilter() );
  innerWatch.m_Prefix = "    ";
  CommandType::Pointer innerCommand = CommandType::New();
  innerCommand->SetCallbackFunction(&innerWatch,
                               &ShowProgressPDEObject::ShowProgress);
  registrator->GetRegistrationFilter()->
    AddObserver(itk::ProgressEvent(), innerCommand);

  // make registration inplace
  registrator->GetModifiableRegistrationFilter()->InPlaceOn();

  registrator->Update();


  // -------------------------------------------------------
  std::cout << "Warp moving image" << std::endl;

  typedef itk::WarpImageFilter<ImageType,ImageType,FieldType> WarperType;
  WarperType::Pointer warper = WarperType::New();

  typedef WarperType::CoordRepType CoordRepType;
  typedef itk::NearestNeighborInterpolateImageFunction<ImageType,CoordRepType>
    InterpolatorType;
  InterpolatorType::Pointer interpolator = InterpolatorType::New();


  warper->SetInput( moving );
  warper->SetDisplacementField( registrator->GetOutput() );
  warper->SetInterpolator( interpolator );
  warper->SetOutputSpacing( fixed->GetSpacing() );
  warper->SetOutputOrigin( fixed->GetOrigin() );

  warper->Update();

  typedef itk::ImageFileWriter<ImageType> WriterType;
  WriterType::Pointer writer = WriterType::New();
  writer->SetInput( warper->GetOutput() );
  writer->SetFileName( argv[1] );
  writer->Update();

  // ---------------------------------------------------------
  std::cout << "Compare warped moving and fixed." << std::endl;

  // compare the warp and fixed images
  itk::ImageRegionIterator<ImageType> fixedIter( fixed,
      fixed->GetBufferedRegion() );
  itk::ImageRegionIterator<ImageType> warpedIter( warper->GetOutput(),
      warper->GetOutput()->GetBufferedRegion() );

  unsigned int numPixelsDifferent = 0;
  while( !fixedIter.IsAtEnd() )
    {
    if( itk::Math::abs( fixedIter.Get() - warpedIter.Get() ) >
        0.1 * itk::Math::abs( fgnd - bgnd ) )
      {
      numPixelsDifferent++;
      }
    ++fixedIter;
    ++warpedIter;
    }

  std::cout << "Number of pixels different: " << numPixelsDifferent;
  std::cout << std::endl;

  //-------------------------------------------------------------
  std::cout << "Test when last shrink factors are not ones." << std::endl;

  registrator->SetNumberOfLevels( 1 );
  registrator->GetModifiableFixedImagePyramid()->SetStartingShrinkFactors( 2 );

  unsigned int n = 5;
  registrator->SetNumberOfIterations( &n );

  registrator->Update();

  if( registrator->GetOutput()->GetBufferedRegion() !=
   fixed->GetBufferedRegion() )
    {
    std::cout << "Deformation field should be the same size as fixed";
    std::cout << std::endl;
    return EXIT_FAILURE;
    }

  // Exercise Get Methods
  std::cout << "RegistrationFilter: " << registrator->GetRegistrationFilter() << std::endl;
  std::cout << "FixedImage: " << registrator->GetFixedImage() << std::endl;
  std::cout << "MovingImage: " << registrator->GetMovingImage() << std::endl;
  std::cout << "FixedImagePyramid: " << registrator->GetFixedImagePyramid() << std::endl;
  std::cout << "MovingImagePyramid: " << registrator->GetMovingImagePyramid() << std::endl;
  std::cout << "NumberOfLevels: " << registrator->GetNumberOfLevels() << std::endl;
  std::cout << "CurrentLevel: " << registrator->GetCurrentLevel() << std::endl;
  std::cout << "NumberOfIterations[0]: " << registrator->GetNumberOfIterations()[0] << std::endl;

  // Exercise error handling
  bool passed;

  typedef RegistrationType::RegistrationType InternalRegistrationType;
  InternalRegistrationType::Pointer demons = registrator->GetModifiableRegistrationFilter();

  try
    {
    passed = false;
    std::cout << "Set RegistrationFilter to ITK_NULLPTR" << std::endl;
    registrator->SetRegistrationFilter( ITK_NULLPTR );
    registrator->Update();
    }
  catch( itk::ExceptionObject& err )
    {
    std::cout << err << std::endl;
    passed = true;
    registrator->ResetPipeline();
    registrator->SetRegistrationFilter( demons );
    }

  if ( !passed )
    {
    std::cout << "Test failed" << std::endl;
    }

  typedef RegistrationType::FixedImagePyramidType FixedImagePyramidType;
  FixedImagePyramidType::Pointer fixedPyramid = registrator->GetModifiableFixedImagePyramid();

  try
    {
    passed = false;
    std::cout << "Set FixedImagePyramid to ITK_NULLPTR" << std::endl;
    registrator->SetFixedImagePyramid( ITK_NULLPTR );
    registrator->Update();
    }
  catch( itk::ExceptionObject& err )
    {
    std::cout << err << std::endl;
    passed = true;
    registrator->ResetPipeline();
    registrator->SetFixedImagePyramid( fixedPyramid );
    }

  if ( !passed )
    {
    std::cout << "Test failed" << std::endl;
    return EXIT_FAILURE;
   }

  typedef RegistrationType::MovingImagePyramidType MovingImagePyramidType;
  MovingImagePyramidType::Pointer movingPyramid = registrator->GetModifiableMovingImagePyramid();

  try
    {
    passed = false;
    std::cout << "Set MovingImagePyramid to ITK_NULLPTR" << std::endl;
    registrator->SetMovingImagePyramid( ITK_NULLPTR );
    registrator->Update();
    }
  catch( itk::ExceptionObject& err )
    {
    std::cout << err << std::endl;
    passed = true;
    registrator->ResetPipeline();
    registrator->SetMovingImagePyramid( movingPyramid );
    }

  if ( !passed )
    {
    std::cout << "Test failed" << std::endl;
    return EXIT_FAILURE;
    }


  try
    {
    passed = false;
    std::cout << "Set FixedImage to ITK_NULLPTR" << std::endl;
    registrator->SetFixedImage( ITK_NULLPTR );
    registrator->Update();
    }
  catch( itk::ExceptionObject& err )
    {
    std::cout << err << std::endl;
    passed = true;
    registrator->ResetPipeline();
    registrator->SetFixedImage( fixed );
    }

  if ( !passed )
    {
    std::cout << "Test failed" << std::endl;
    return EXIT_FAILURE;
    }

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

}