/*=========================================================================
 *
 *  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.
 *
 *=========================================================================*/
#ifndef itkSimilarityIndexImageFilter_hxx
#define itkSimilarityIndexImageFilter_hxx
#include "itkSimilarityIndexImageFilter.h"

#include "itkImageRegionIterator.h"
#include "itkProgressReporter.h"
#include "itkMath.h"

namespace itk
{
template< typename TInputImage1, typename TInputImage2 >
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::SimilarityIndexImageFilter():m_CountOfImage1(1), m_CountOfImage2(1), m_CountOfIntersection(1)
{
  // this filter requires two input images
  this->SetNumberOfRequiredInputs(2);

  m_SimilarityIndex = NumericTraits< RealType >::ZeroValue();
  this->DynamicMultiThreadingOff();
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::SetInput2(const TInputImage2 *image)
{
  this->SetNthInput( 1, const_cast< TInputImage2 * >( image ) );
}

template< typename TInputImage1, typename TInputImage2 >
const typename SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::InputImage2Type *
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::GetInput2()
{
  return itkDynamicCastInDebugMode< const TInputImage2 * >
    ( this->ProcessObject::GetInput(1) );
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::GenerateInputRequestedRegion()
{
  Superclass::GenerateInputRequestedRegion();

  // this filter requires:
  // - the largeset possible region of the first image
  // - the corresponding region of the second image
  if ( this->GetInput1() )
    {
    InputImage1Pointer image1 =
      const_cast< InputImage1Type * >( this->GetInput1() );
    image1->SetRequestedRegionToLargestPossibleRegion();

    if ( this->GetInput2() )
      {
      InputImage2Pointer image2 =
        const_cast< InputImage2Type * >( this->GetInput2() );
      image2->SetRequestedRegion(
        this->GetInput1()->GetRequestedRegion() );
      }
    }
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::EnlargeOutputRequestedRegion(DataObject *data)
{
  Superclass::EnlargeOutputRequestedRegion(data);
  data->SetRequestedRegionToLargestPossibleRegion();
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::AllocateOutputs()
{
  // Pass the first input through as the output
  InputImage1Pointer image =
    const_cast< TInputImage1 * >( this->GetInput1() );

  this->GraftOutput(image);
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::BeforeThreadedGenerateData()
{
  ThreadIdType numberOfThreads = this->GetNumberOfWorkUnits();

  // Resize the thread temporaries
  m_CountOfImage1.SetSize(numberOfThreads);
  m_CountOfImage2.SetSize(numberOfThreads);
  m_CountOfIntersection.SetSize(numberOfThreads);

  // Initialize the temporaries
  m_CountOfImage1.Fill(NumericTraits< SizeValueType >::ZeroValue());
  m_CountOfImage2.Fill(NumericTraits< SizeValueType >::ZeroValue());
  m_CountOfIntersection.Fill(NumericTraits< SizeValueType >::ZeroValue());
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::AfterThreadedGenerateData()
{
  ThreadIdType           i;
  SizeValueType countImage1, countImage2, countIntersect;

  ThreadIdType numberOfThreads = this->GetNumberOfWorkUnits();

  countImage1 = 0;
  countImage2 = 0;
  countIntersect = 0;

  // Accumulate counts over all threads
  for ( i = 0; i < numberOfThreads; i++ )
    {
    countImage1 += m_CountOfImage1[i];
    countImage2 += m_CountOfImage2[i];
    countIntersect += m_CountOfIntersection[i];
    }

  // compute overlap
  if ( !countImage1 && !countImage2 )
    {
    m_SimilarityIndex = NumericTraits< RealType >::ZeroValue();
    return;
    }

  m_SimilarityIndex = 2.0 * static_cast< RealType >( countIntersect )
                      / ( static_cast< RealType >( countImage1 ) + static_cast< RealType >( countImage2 ) );
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::ThreadedGenerateData(const RegionType & outputRegionForThread,
                       ThreadIdType threadId)
{
  ImageRegionConstIterator< TInputImage1 > it1 (this->GetInput1(), outputRegionForThread);
  ImageRegionConstIterator< TInputImage2 > it2 (this->GetInput2(), outputRegionForThread);

  // support progress methods/callbacks
  ProgressReporter progress( this, threadId, outputRegionForThread.GetNumberOfPixels() );

  // do the work
  while ( !it1.IsAtEnd() )
    {
    bool nonzero = false;
    if ( it1.Get() != NumericTraits< InputImage1PixelType >::ZeroValue() )
      {
      m_CountOfImage1[threadId]++;
      nonzero = true;
      }
    if ( Math::NotExactlyEquals(it2.Get(), NumericTraits< InputImage2PixelType >::ZeroValue()) )
      {
      m_CountOfImage2[threadId]++;
      if ( nonzero )
        {
        m_CountOfIntersection[threadId]++;
        }
      }
    ++it1;
    ++it2;

    progress.CompletedPixel();
    }
}

template< typename TInputImage1, typename TInputImage2 >
void
SimilarityIndexImageFilter< TInputImage1, TInputImage2 >
::PrintSelf(std::ostream & os, Indent indent) const
{
  Superclass::PrintSelf(os, indent);

  os << indent << "SimilarityIndex: "  << m_SimilarityIndex << std::endl;
}
} // end namespace itk
#endif
