#include <Rcpp.h>
// Copyright (c) 2005-2008  INRIA Sophia-Antipolis (France).
//               2008 GeometryFactory
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1/CGAL_ImageIO/include/CGAL/IO/read_vtk_image_data.h $
// $Id: include/CGAL/IO/read_vtk_image_data.h b26b07a1242 $
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Laurent Rineau, Pierre Alliez

#ifndef CGAL_IO_READ_VTK_IMAGE_DATA_H
#define CGAL_IO_READ_VTK_IMAGE_DATA_H

#include <CGAL/Image_3.h>
#include <CGAL/Image_3_vtk_interface.h>

namespace CGAL {

namespace {

struct VTK_to_ImageIO_type_mapper {
  WORD_KIND wordKind;
  SIGN sign;
  unsigned int wdim;
};

static const VTK_to_ImageIO_type_mapper VTK_to_ImageIO_type[VTK_ID_TYPE] =
  { { WK_UNKNOWN, SGN_UNKNOWN,  0}, //  0=VTK_VOID
    { WK_UNKNOWN, SGN_UNKNOWN,  0}, //  1=VTK_BIT
    { WK_FIXED,   SGN_SIGNED,   1}, //  2=VTK_CHAR
    { WK_FIXED,   SGN_UNSIGNED, 1}, //  3=VTK_UNSIGNED_CHAR
    { WK_FIXED,   SGN_SIGNED,   2}, //  4=VTK_SHORT
    { WK_FIXED,   SGN_UNSIGNED, 2}, //  5=VTK_UNSIGNED_SHORT
    { WK_FIXED,   SGN_SIGNED,   4}, //  6=VTK_INT
    { WK_FIXED,   SGN_UNSIGNED, 4}, //  7=VTK_UNSIGNED_INT
    { WK_FIXED,   SGN_SIGNED,   8}, //  8=VTK_LONG
    { WK_FIXED,   SGN_UNSIGNED, 8}, //  9=VTK_UNSIGNED_LONG
    { WK_FLOAT,   SGN_SIGNED,   4}, // 10=VTK_FLOAT
    { WK_FIXED,   SGN_SIGNED,   8}  // 11=VTK_DOUBLE
 };

} //end anonymous namespace

namespace IO {

inline
Image_3
read_vtk_image_data(vtkImageData* vtk_image, Image_3::Own owning = Image_3::OWN_THE_DATA)
{
  if(!vtk_image)
    return Image_3();

  _image* image = ::_initImage();
  const int* dims = vtk_image->GetDimensions();
  const double* spacing = vtk_image->GetSpacing();
  const double* offset = vtk_image->GetOrigin();
  image->vectMode = VM_SCALAR;
  image->xdim = dims[0];
  image->ydim = dims[1];
  image->zdim = dims[2];
  image->vdim = 1;
  image->vx = (spacing[0] == 0) ? 1 : spacing[0];
  image->vy = (spacing[1] == 0) ? 1 : spacing[1];
  image->vz = (spacing[2] == 0) ? 1 : spacing[2];
  image->tx = static_cast<float>(offset[0]);
  image->ty = static_cast<float>(offset[1]);
  image->tz = static_cast<float>(offset[2]);
  image->endianness = ::_getEndianness();

  int vtk_type = vtk_image->GetScalarType();
  if(vtk_type == VTK_SIGNED_CHAR) vtk_type = VTK_CHAR;
  if(vtk_type < 0 || vtk_type > VTK_DOUBLE) vtk_type = VTK_DOUBLE;
  const VTK_to_ImageIO_type_mapper& imageio_type = VTK_to_ImageIO_type[vtk_type];
  image->wdim = imageio_type.wdim;
  image->wordKind = imageio_type.wordKind;
  image->sign = imageio_type.sign;

  const int cn = vtk_image->GetNumberOfScalarComponents();

  if (!vtk_image->GetPointData() || !vtk_image->GetPointData()->GetScalars()) {
    ::_freeImage(image);
    return Image_3();
  }

  // If there is more than a scalar per point, vtk_image->data is not immediately
  // interpretable in Image_3->data
  CGAL_assertion(owning == Image_3::OWN_THE_DATA || cn == 1);
  CGAL_assertion(vtk_image->GetPointData()->GetScalars()->GetNumberOfTuples() == static_cast<vtkIdType>(image->xdim*image->ydim*image->zdim));

  if(owning == Image_3::OWN_THE_DATA) {
    std::size_t dims_n = image->xdim*image->ydim*image->zdim;
    image->data = ::ImageIO_alloc(dims_n * image->wdim);

    // Rcpp::Rcerr << "GetNumberOfTuples() = " << vtk_image->GetPointData()->GetScalars()->GetNumberOfTuples() << "\n"
    //           << "components = " << cn << "\n"
    //           << "wdim = " << image->wdim << "\n"
    //           << "image->size() = " << dims_n << std::endl;

    if(cn == 1) {
      vtk_image->GetPointData()->GetScalars()->ExportToVoidPointer(image->data);
    } else {
      Rcpp::Rcerr << "Warning: input has " << cn << " components; only the value of the first component will be used." << std::endl;
      CGAL_assertion(cn >= 3); // if it's more than 1, it needs to be at least 3

      // cast the data void pointers to make it possible to do pointer arithmetic
      char* src = static_cast<char*>(vtk_image->GetPointData()->GetScalars()->GetVoidPointer(0));
      char* dest = static_cast<char*>(image->data);

      for(std::size_t i=0; i<dims_n; ++i)
      {
        // multiply by image->wdim because we casted to char* and not the actual data type
        memcpy(dest + image->wdim*i, src + cn*image->wdim*i, image->wdim);

        // Check that we are not discarding useful data (i.e., green & blue are identical to red)
        CGAL_assertion(memcmp(src + cn*image->wdim*i, src + cn*image->wdim*i + image->wdim, image->wdim) == 0);
        CGAL_assertion(memcmp(src + cn*image->wdim*i, src + cn*image->wdim*i + 2*image->wdim, image->wdim) == 0);
      }
    }
  } else {
    image->data = vtk_image->GetPointData()->GetScalars()->GetVoidPointer(0);
  }

  return Image_3(image, owning);
}

} // namespace IO

#ifndef CGAL_NO_DEPRECATED_CODE
using IO::read_vtk_image_data;
#endif

} // namespace CGAL


#endif // CGAL_IO_READ_VTK_IMAGE_DATA_H

