// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
/**
 * @class   vtkStructuredNeighbor
 * @brief   An internal, light-weight class used to store neighbor information.
 */

#ifndef vtkStructuredNeighbor_h
#define vtkStructuredNeighbor_h

#include "vtkFiltersGeometryModule.h" // For export macro
#include "vtkObject.h"

VTK_ABI_NAMESPACE_BEGIN
class VTKFILTERSGEOMETRY_EXPORT vtkStructuredNeighbor
{
public:
  // An enum that defines the neighboring orientation which is stored in a
  // 3-tuple vtkStructuredNeighbor::Orientation. In each dimension, there
  // is a high and low end, the orientation tuple defines how to grow ghost
  // layers along each dimension.
  enum NeighborOrientation
  {
    SUBSET_LO = -2,  // The grid is a subset of the neighboring grid and the
                     // ghost layers are pointing away from the low end
    LO = -1,         // The grid partially overlap with its neighbor on the
                     // low end, thus, ghost layers are pointing away from
                     // the low end
    ONE_TO_ONE = 0,  // grids abut 1-to-1 in both HI and LO, the
                     // cardinality of both grids is the same in the
                     // corresponding dimension.
    HI = 1,          // The grid partially overlaps with its neighbor on the
                     // high end, thus, ghost layers are pointing away from
                     // the high end
    SUBSET_HI = 2,   // The grid is a subset of the neighboring grid and the
                     // ghost layers are pointing away from the high end
    SUBSET_BOTH = 3, // The grid is a subset of the neighboring grid and the
                     // ghost layers grow from both low and high ends.
    SUPERSET = 4,    // grid is a superset of the neighboring grid in the
                     // given direction.
    UNDEFINED = 5    // the neighboring relationship is undefined, e.g., if
                     // we are checking 2D data, the neighbor orientation
                     // in the 3rd dimension is undefined.
  };

  // Class Member Variables made public for easier access
  int NeighborID;       // The registered ID of the neighboring grid
  int OverlapExtent[6]; // The extent at which the grids overlap
  int SendExtent[6];    // The extent that we send to this neighbor
  int RcvExtent[6];     // The extent that we receive from this neighbor
  int Orientation[3];   // Defines how we are neighboring with this grid, see
                        // NeighborOrientation enum above.

  /**
   * Default Constructor
   */
  vtkStructuredNeighbor();

  /**
   * Custom constructor. Constructs a neighbor with the prescribed neighbor
   * grid/block ID and overlap.
   */
  vtkStructuredNeighbor(int NeiID, int overlap[6]);

  /**
   * Custom constructor. Constructs a neighbor with the prescribed neighbor
   * grid/block ID, overlap extent, and orientation
   */
  vtkStructuredNeighbor(int NeiID, int overlap[6], int orient[3]);

  /**
   * Copy constructor
   */
  vtkStructuredNeighbor(const vtkStructuredNeighbor& N) { *this = N; }

  /**
   * Default destructor
   */
  virtual ~vtkStructuredNeighbor();

  ///@{
  /**
   * Overload assignment operator
   */
  vtkStructuredNeighbor& operator=(const vtkStructuredNeighbor& N)
  {
    if (this != &N)
    {
      this->Orientation[0] = N.Orientation[0];
      this->Orientation[1] = N.Orientation[1];
      this->Orientation[2] = N.Orientation[2];
      this->NeighborID = N.NeighborID;
      for (int i = 0; i < 6; ++i)
      {
        this->SendExtent[i] = N.SendExtent[i];
        this->RcvExtent[i] = N.RcvExtent[i];
        this->OverlapExtent[i] = N.OverlapExtent[i];
      } // END for
    }   // END if
    return *this;
  }
  ///@}

  ///@{
  /**
   * Computes the SendExtent and the RcvExtent for this neighbor. The method
   * assumes that the overlap extent and orientation are already computed.
   * Using this information, the method grows the overlap extent to form the
   * Send and Rcv Extents for this neighbor instance.
   */
  virtual void ComputeSendAndReceiveExtent(int gridRealExtent[6], int gridGhostedExtent[6],
    int neiRealExtent[6], int WholeExtent[6], int N);
  ///@}
};

VTK_ABI_NAMESPACE_END
#endif /* vtkStructuredNeighbor_h */
// VTK-HeaderTest-Exclude: vtkStructuredNeighbor.h
