// =========================================================================
// @author Leonardo Florez Valencia
// @email florez-l@javeriana.edu.co
// =========================================================================
#ifndef __fpa__Filters__Image__RandomWalker__hxx__
#define __fpa__Filters__Image__RandomWalker__hxx__

#include <itkImageRegionConstIteratorWithIndex.h>

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
typename
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
TCostsImage*
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
GetOutputCosts( )
{
  return( this->GetOutput( ) );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
const typename
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
TCostsImage*
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
GetOutputCosts( ) const
{
  return( this->GetOutput( ) );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
typename
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
TOutputLabels*
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
GetOutputLabels( )
{
  return( this->GetMarks( ) );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
const typename
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
TOutputLabels*
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
GetOutputLabels( ) const
{
  return( this->GetMarks( ) );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
typename
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
TInputImage*
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
GetInputImage( )
{
  return( this->GetInput( ) );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
const typename
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
TInputImage*
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
GetInputImage( ) const
{
  return( this->GetInput( ) );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
void
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
SetInputImage( TInputImage* image )
{
  this->SetInput( image );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
RandomWalker( )
  : Superclass( )
{
  fpaFilterInputConfigureMacro( InputLabels, TInputLabels );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
~RandomWalker( )
{
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
const itk::DataObject*
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
_GetReferenceInput( ) const
{
  return( this->GetInputLabels( ) );
}

// -------------------------------------------------------------------------
template< class _TInputImage, class _TInputLabels, class _TCostsImage, class _TTraits >
void
fpa::Filters::Image::RandomWalker< _TInputImage, _TInputLabels, _TCostsImage, _TTraits >::
_PrepareSeeds( const itk::DataObject* input )
{
  // Input object is a labelled image?
  const TInputLabels* labels = dynamic_cast< const TInputLabels* >( input );
  if( labels != NULL )
  {
    this->m_UnifiedSeeds.clear( );

    // Iterate over labels
    typedef itk::ImageRegionConstIteratorWithIndex< TInputLabels > _TIt;
    typename TInputLabels::RegionType reg = labels->GetRequestedRegion( );
    _TIt lIt( labels, reg );
    for( lIt.GoToBegin( ); !lIt.IsAtEnd( ); ++lIt )
    {
      if( lIt.Get( ) > 0 )
      {
        bool is_seed = false;
        for( unsigned int d = 0; d < Self::Dimension; ++d )
        {
          for( int s = -1; s <= 1; s += 2 )
          {
            TVertex neigh = lIt.GetIndex( );
            neigh[ d ] += s;
            if( reg.IsInside( neigh ) )
              is_seed |= ( labels->GetPixel( neigh ) == 0 );

          } // rof

        } // rof

        // Add pixel as seed or already marked
        TNode node;
        node.Vertex = lIt.GetIndex( );
        node.Parent = lIt.GetIndex( );
        node.FrontId = lIt.Get( );
        node.Value = TOutputValue( 0 );
        if( !is_seed )
        {
          this->_Mark( node.Vertex, node.FrontId );
          this->_UpdateOutputValue( node );
        }
        else
          this->m_UnifiedSeeds.insert( node );

      } // fi

    } // rof

  } // fi
}

#endif // __fpa__Filters__Image__RandomWalker__hxx__
// eof - $RCSfile$