#include <cmath>
#include <ctime>
#include <deque>
#include <iostream>
#include <limits>
#include <map>
#include <string>

#include <itkConstNeighborhoodIterator.h>
#include <itkNeighborhoodIterator.h>
#include <itkDanielssonDistanceMapImageFilter.h>
#include <itkImage.h>
#include <itkImageFileReader.h>
#include <itkImageFileWriter.h>
#include <itkImageToVTKImageFilter.h>

#include <vtkPoints.h>
#include <vtkCellArray.h>
#include <vtkFloatArray.h>
#include <vtkPolyData.h>
#include <vtkSmartPointer.h>

#include <fpa/Image/DijkstraWithSphereBacktracking.h>
#include <fpa/VTK/ImageMPR.h>
#include <fpa/VTK/Image3DObserver.h>

// -------------------------------------------------------------------------
const unsigned int Dim = 3;
typedef double                               TPixel;
typedef double                               TScalar;
typedef itk::Image< TPixel, Dim >            TImage;
typedef itk::ImageToVTKImageFilter< TImage > TVTKImage;

typedef itk::ImageFileReader< TImage >          TImageReader;
typedef itk::ImageFileWriter< TImage >          TImageWriter;
typedef fpa::Image::DijkstraWithSphereBacktracking< TImage, TScalar > TDijkstra;

typedef fpa::VTK::ImageMPR TMPR;
typedef fpa::VTK::Image3DObserver< TDijkstra, vtkRenderWindow > TDijkstraObs;

// -------------------------------------------------------------------------
int main( int argc, char* argv[] )
{
  if( argc < 6 )
  {
    std::cerr
      << "Usage: " << argv[ 0 ]
      << " input_image x y z output_image"
      << " visual_debug"
      << std::endl;
    return( 1 );

  } // fi
  std::string input_image_fn = argv[ 1 ];
  TImage::IndexType seed_idx;
  seed_idx[ 0 ] = std::atoi( argv[ 2 ] );
  seed_idx[ 1 ] = std::atoi( argv[ 3 ] );
  seed_idx[ 2 ] = std::atoi( argv[ 4 ] );
  std::string output_image_fn = argv[ 5 ];
  bool visual_debug = false;
  if( argc > 6 )
    visual_debug = ( std::atoi( argv[ 6 ] ) == 1 );

  // Read image
  TImageReader::Pointer input_image_reader = TImageReader::New( );
  input_image_reader->SetFileName( input_image_fn );
  try
  {
    input_image_reader->Update( );
  }
  catch( itk::ExceptionObject& err )
  {
    std::cerr << "Error caught: " << err << std::endl;
    return( 1 );

  } // yrt
  TImage::ConstPointer input_image = input_image_reader->GetOutput( );

  // Show image
  TVTKImage::Pointer vtk_image = TVTKImage::New( );
  vtk_image->SetInput( input_image );
  vtk_image->Update( );

  TMPR view;
  view.SetBackground( 0.3, 0.2, 0.8 );
  view.SetSize( 800, 800 );
  view.SetImage( vtk_image->GetOutput( ) );

  // Allow some interaction
  view.Start( );

  // Extract paths
  TDijkstra::Pointer paths = TDijkstra::New( );
  paths->AddSeed( seed_idx, TScalar( 0 ) );
  paths->SetInput( input_image );
  paths->SetNeighborhoodOrder( 1 );

  if( visual_debug )
  {
    // Configure observer
    TDijkstraObs::Pointer obs = TDijkstraObs::New( );
    obs->SetRenderWindow( view.GetWindow( ) );
    paths->AddObserver( itk::AnyEvent( ), obs );
    paths->ThrowEventsOn( );
  }
  else
    paths->ThrowEventsOff( );
  std::clock_t start = std::clock( );
  paths->Update( );
  std::clock_t end = std::clock( );
  double seconds = double( end - start ) / double( CLOCKS_PER_SEC );
  std::cout << "Paths extraction time = " << seconds << std::endl;

  // Create polydata
  vtkSmartPointer< vtkPoints > points =
    vtkSmartPointer< vtkPoints >::New( );
  vtkSmartPointer< vtkCellArray > cells =
    vtkSmartPointer< vtkCellArray >::New( );
  vtkSmartPointer< vtkFloatArray > scalars =
    vtkSmartPointer< vtkFloatArray >::New( );

  const TDijkstra::TVertices& endpoints = paths->GetEndPoints( );
  const TDijkstra::TTree& tree = paths->GetFinalTree( );
  TDijkstra::TVertices::const_iterator epIt = endpoints.begin( );
  for( unsigned int epId = 0; epIt != endpoints.end( ); ++epIt, ++epId )
  {
    double pd = double( epId ) / double( endpoints.size( ) - 1 );

    TDijkstra::TVertex idx = *epIt;
    do
    {
      TImage::PointType pnt;
      input_image->TransformIndexToPhysicalPoint( idx, pnt );

      points->InsertNextPoint( pnt[ 0 ], pnt[ 1 ], pnt[ 2 ] );
      scalars->InsertNextTuple1( pd );
      if( idx != *epIt )
      {
        cells->InsertNextCell( 2 );
        cells->InsertCellPoint( points->GetNumberOfPoints( ) - 2 );
        cells->InsertCellPoint( points->GetNumberOfPoints( ) - 1 );

      } // fi
      idx = tree.find( idx )->second;

    } while( idx != tree.find( idx )->second );

  } // rof

  vtkSmartPointer< vtkPolyData > vtk_tree =
    vtkSmartPointer< vtkPolyData >::New( );
  vtk_tree->SetPoints( points );
  vtk_tree->SetLines( cells );
  vtk_tree->GetPointData( )->SetScalars( scalars );

  view.AddPolyData( vtk_tree );
  view.Render( );
  view.Start( );

  /* TODO
     TImageWriter::Pointer dijkstra_writer =
     TImageWriter::New( );
     dijkstra_writer->SetInput( paths->GetOutput( ) );
     dijkstra_writer->SetFileName( "dijkstra.mhd" );
     dijkstra_writer->Update( );
  */

  return( 0 );
}

// eof - $RCSfile$