// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
/**
 * @class   vtkGenericEdgeTable
 * @brief   keep track of edges (defined by pair of integer id's)
 *
 * vtkGenericEdgeTable is used to indicate the existence of and hold
 * information about edges. Similar to vtkEdgeTable, this class is
 * more sophisticated in that it uses reference counting to keep track
 * of when information about an edge should be deleted.
 *
 * vtkGenericEdgeTable is a helper class used in the adaptor framework.  It
 * is used during the tessellation process to hold information about the
 * error metric on each edge. This avoids recomputing the error metric each
 * time the same edge is visited.
 */

#ifndef vtkGenericEdgeTable_h
#define vtkGenericEdgeTable_h

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

VTK_ABI_NAMESPACE_BEGIN
class vtkEdgeTableEdge;
class vtkEdgeTablePoints;

class VTKCOMMONDATAMODEL_EXPORT vtkGenericEdgeTable : public vtkObject
{
public:
  /**
   * Instantiate an empty edge table.
   */
  static vtkGenericEdgeTable* New();

  ///@{
  /**
   * Standard VTK type and print macros.
   */
  vtkTypeMacro(vtkGenericEdgeTable, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;
  ///@}

  /**
   * Split the edge with the indicated point id.
   */
  void InsertEdge(vtkIdType e1, vtkIdType e2, vtkIdType cellId, int ref, vtkIdType& ptId);

  /**
   * Insert an edge but do not split it.
   */
  void InsertEdge(vtkIdType e1, vtkIdType e2, vtkIdType cellId, int ref = 1);

  /**
   * Method to remove an edge from the table. The method returns the
   * current reference count.
   */
  int RemoveEdge(vtkIdType e1, vtkIdType e2);

  /**
   * Method to determine whether an edge is in the table (0 or 1), or not (-1).
   * It returns whether the edge was split (1) or not (0),
   * and the point id exists.
   */
  int CheckEdge(vtkIdType e1, vtkIdType e2, vtkIdType& ptId);

  /**
   * Method that increments the referencecount and returns it.
   */
  int IncrementEdgeReferenceCount(vtkIdType e1, vtkIdType e2, vtkIdType cellId);

  /**
   * Return the edge reference count.
   */
  int CheckEdgeReferenceCount(vtkIdType e1, vtkIdType e2);

  /**
   * To specify the starting point id. It will initialize LastPointId
   * This is very sensitive the start point should be cautiously chosen
   */
  void Initialize(vtkIdType start);

  /**
   * Return the total number of components for the point-centered attributes.
   * \post positive_result: result>0
   */
  int GetNumberOfComponents();

  /**
   * Set the total number of components for the point-centered attributes.
   * \pre positive_count: count>0
   */
  void SetNumberOfComponents(int count);

  /**
   * Check if a point is already in the point table.
   */
  int CheckPoint(vtkIdType ptId);

  /**
   * Check for the existence of a point and return its coordinate value.
   * \pre scalar_size: sizeof(scalar)==this->GetNumberOfComponents()
   */
  int CheckPoint(vtkIdType ptId, double point[3], double* scalar);

  ///@{
  /**
   * Insert point associated with an edge.
   */
  void InsertPoint(vtkIdType ptId, double point[3]);
  // \pre: sizeof(s)==GetNumberOfComponents()
  void InsertPointAndScalar(vtkIdType ptId, double pt[3], double* s);
  ///@}

  /**
   * Remove a point from the point table.
   */
  void RemovePoint(vtkIdType ptId);

  /**
   * Increment the reference count for the indicated point.
   */
  void IncrementPointReferenceCount(vtkIdType ptId);

  ///@{
  /**
   * For debugging purposes. It is particularly useful to dump the table
   * and check that nothing is left after a complete iteration. LoadFactor
   * should ideally be very low to be able to have a constant time access
   */
  void DumpTable();
  void LoadFactor();
  ///@}

  class PointEntry
  {
  public:
    vtkIdType PointId;
    double Coord[3];
    double* Scalar; // point data: all point-centered attributes at this point
    int numberOfComponents;

    int Reference; // signed char

    /**
     * Constructor with a scalar field of `size' doubles.
     * \pre positive_number_of_components: size>0
     */
    PointEntry(int size);

    ~PointEntry() { delete[] this->Scalar; }

    PointEntry(const PointEntry& other)
    {
      this->PointId = other.PointId;

      memcpy(this->Coord, other.Coord, sizeof(double) * 3);

      int c = other.numberOfComponents;
      this->numberOfComponents = c;
      this->Scalar = new double[c];
      memcpy(this->Scalar, other.Scalar, sizeof(double) * c);
      this->Reference = other.Reference;
    }

    PointEntry& operator=(const PointEntry& other)
    {
      if (this != &other)
      {
        this->PointId = other.PointId;

        memcpy(this->Coord, other.Coord, sizeof(double) * 3);

        int c = other.numberOfComponents;

        if (this->numberOfComponents != c)
        {
          delete[] this->Scalar;
          this->Scalar = new double[c];
          this->numberOfComponents = c;
        }
        memcpy(this->Scalar, other.Scalar, sizeof(double) * c);
        this->Reference = other.Reference;
      }
      return *this;
    }
  };

  class EdgeEntry
  {
  public:
    vtkIdType E1;
    vtkIdType E2;

    int Reference; // signed char
    int ToSplit;   // signed char
    vtkIdType PtId;
    vtkIdType CellId; // CellId the edge refer to at a step in tessellation

    EdgeEntry()
    {
      this->Reference = 0;
      this->CellId = -1;
    }
    ~EdgeEntry() = default;

    EdgeEntry(const EdgeEntry& copy)
    {
      this->E1 = copy.E1;
      this->E2 = copy.E2;

      this->Reference = copy.Reference;
      this->ToSplit = copy.ToSplit;
      this->PtId = copy.PtId;
      this->CellId = copy.CellId;
    }

    EdgeEntry& operator=(const EdgeEntry& entry)
    {
      if (this == &entry)
      {
        return *this;
      }
      this->E1 = entry.E1;
      this->E2 = entry.E2;
      this->Reference = entry.Reference;
      this->ToSplit = entry.ToSplit;
      this->PtId = entry.PtId;
      this->CellId = entry.CellId;
      return *this;
    }
  };

protected:
  vtkGenericEdgeTable();
  ~vtkGenericEdgeTable() override;

  /**
   * Split the edge with the indicated point id.
   */
  void InsertEdge(
    vtkIdType e1, vtkIdType e2, vtkIdType cellId, int ref, int toSplit, vtkIdType& ptId);

  // Hash table that contiain entry based on edges:
  vtkEdgeTableEdge* EdgeTable;

  // At end of process we should be able to retrieve points coord based on pointid
  vtkEdgeTablePoints* HashPoints;

  // Main hash functions
  // For edge table:
  vtkIdType HashFunction(vtkIdType e1, vtkIdType e2);

  // For point table:
  vtkIdType HashFunction(vtkIdType ptId);

  // Keep track of the last point id we inserted, increment it each time:
  vtkIdType LastPointId;

  vtkIdType NumberOfComponents;

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

VTK_ABI_NAMESPACE_END
#endif