/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkBridgeCellIteratorOne.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
/**
 * @class   vtkBridgeCellIteratorOne
 * @brief   Iterate over one cell only of a dataset.
 * @sa
 * vtkBridgeCellIterator, vtkBridgeDataSet, vtkBridgeCellIteratorStrategy
*/

#ifndef vtkBridgeCellIteratorOne_h
#define vtkBridgeCellIteratorOne_h

#include "vtkBridgeCellIteratorStrategy.h"

class vtkBridgeCell;
class vtkBridgeDataSet;
class vtkBridgeCell;
class vtkIdList;
class vtkPoints;
class vtkCell;

class VTKTESTINGGENERICBRIDGE_EXPORT vtkBridgeCellIteratorOne : public vtkBridgeCellIteratorStrategy
{
public:
  static vtkBridgeCellIteratorOne *New();
  vtkTypeMacro(vtkBridgeCellIteratorOne,
                       vtkBridgeCellIteratorStrategy);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  /**
   * Move iterator to first position if any (loop initialization).
   */
  void Begin() override;

  /**
   * Is there no cell at iterator position? (exit condition).
   */
  vtkTypeBool IsAtEnd() override;

  /**
   * Cell at current position
   * \pre not_at_end: !IsAtEnd()
   * \pre c_exists: c!=0
   * THREAD SAFE
   */
  void GetCell(vtkGenericAdaptorCell *c) override;

  /**
   * Cell at current position.
   * NOT THREAD SAFE
   * \pre not_at_end: !IsAtEnd()
   * \post result_exits: result!=0
   */
  vtkGenericAdaptorCell *GetCell() override;

  /**
   * Move iterator to next position. (loop progression).
   * \pre not_at_end: !IsAtEnd()
   */
  void Next() override;

  /**
   * Used internally by vtkBridgeDataSet.
   * Iterate on one cell `id' of `ds'.
   * \pre ds_exists: ds!=0
   * \pre valid_id: (id>=0)&&(id<=ds->GetNumberOfCells())
   */
  void InitWithOneCell(vtkBridgeDataSet *ds,
                       vtkIdType cellid);

  /**
   * Used internally by vtkBridgeCell.
   * Iterate on one cell `c'.
   * \pre c_exists: c!=0
   */
  void InitWithOneCell(vtkBridgeCell *c);

  /**
   * Used internally by vtkBridgeCell.
   * Iterate on a boundary cell (defined by its points `pts' with coordinates
   * `coords', dimension `dim' and unique id `cellid') of a cell.
   * \pre coords_exist: coords!=0
   * \pre pts_exist: pts!=0
   * \pre valid_dim: dim>=0 && dim<=2
   * \pre valid_points: pts->GetNumberOfIds()>dim
   */
  void InitWithPoints(vtkPoints *coords,
                      vtkIdList *pts,
                      int dim,
                      vtkIdType cellid);

protected:
  vtkBridgeCellIteratorOne();
  ~vtkBridgeCellIteratorOne() override;

  int cIsAtEnd;
  vtkBridgeDataSet *DataSet; // the structure on which the object iterates.
  vtkIdType Id; // the id at current position.
  vtkBridgeCell *Cell; // cell at current position.
  vtkCell *InternalCell;

private:
  vtkBridgeCellIteratorOne(const vtkBridgeCellIteratorOne&) = delete;
  void operator=(const vtkBridgeCellIteratorOne&) = delete;
};

#endif
