// Created on: 1998-03-26
// Created by: Robert COUBLANC
// Copyright (c) 1998-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _SelectMgr_SortCriterion_HeaderFile
#define _SelectMgr_SortCriterion_HeaderFile

#include <Graphic3d_Vec3.hxx>
#include <Precision.hxx>
#include <Select3D_SensitiveEntity.hxx>

//! This class provides data and criterion for sorting candidate
//! entities in the process of interactive selection by mouse click
class SelectMgr_SortCriterion 
{
public:

  Handle(Select3D_SensitiveEntity) Entity; //!< detected entity
  gp_Pnt             Point;           //!< 3D point
  Graphic3d_Vec3     Normal;          //!< surface normal or 0 vector if undefined
  Standard_Real      Depth;           //!< distance from the view plane to the entity
  Standard_Real      MinDist;         //!< distance from the clicked point to the entity on the view plane
  Standard_Real      Tolerance;       //!< tolerance used for selecting candidates
  Standard_Integer   Priority;        //!< selection priority
  Standard_Integer   ZLayerPosition;  //!< ZLayer rendering order index, stronger than a depth
  Standard_Integer   NbOwnerMatches;  //!< overall number of entities collected for the same owner

public:
  DEFINE_STANDARD_ALLOC

  //! Empty constructor.
  SelectMgr_SortCriterion()
  : Depth    (0.0),
    MinDist  (0.0),
    Tolerance(0.0),
    Priority (0),
    ZLayerPosition (0),
    NbOwnerMatches (0) {}

  //! Compare with another item by depth, priority and minDist.
  bool IsCloserDepth (const SelectMgr_SortCriterion& theOther) const
  {
    // the object within different ZLayer groups can not be compared by depth
    if (ZLayerPosition != theOther.ZLayerPosition)
    {
      return ZLayerPosition > theOther.ZLayerPosition;
    }

    // closest object is selected if their depths are not equal within tolerance
    if (Abs (Depth - theOther.Depth) > Tolerance + theOther.Tolerance)
    {
      return Depth < theOther.Depth;
    }

    Standard_Real aCos = 1.0;
    if (Normal.Modulus() > 0 && theOther.Normal.Modulus() > 0)
    {
      gp_Dir aNormal (Normal.x(), Normal.y(), Normal.z());
      gp_Dir anOtherNormal (theOther.Normal.x(), theOther.Normal.y(), theOther.Normal.z());
      aCos = Abs (Cos (aNormal.Angle (anOtherNormal)));
    }

    Standard_Real aDepth = Depth - Tolerance;
    Standard_Real anOtherDepth = theOther.Depth - theOther.Tolerance;
    // Comparison depths taking into account tolerances occurs when the surfaces are parallel
    // or have the same sensitivity and the angle between them is less than 60 degrees.
    if (Abs (aDepth - anOtherDepth) > Precision::Confusion())
    {
      if ((aCos > 0.5 && Abs (Tolerance - theOther.Tolerance) < Precision::Confusion())
       || Abs (aCos - 1.0) < Precision::Confusion())
      {
        return aDepth < anOtherDepth;
      }
    }

    // if two objects have similar depth, select the one with higher priority
    if (Priority > theOther.Priority)
    {
      return true;
    }

    // if priorities are equal, one closest to the mouse
    return Priority == theOther.Priority
        && MinDist  <  theOther.MinDist;
  }

  //! Compare with another item using old logic (OCCT version <= 6.3.1) with priority considered preceding depth.
  bool IsHigherPriority (const SelectMgr_SortCriterion& theOther) const
  {
    // the object within different ZLayer groups can not be compared by depth
    if (ZLayerPosition != theOther.ZLayerPosition)
    {
      return ZLayerPosition > theOther.ZLayerPosition;
    }

    if (Priority > theOther.Priority)
    {
      return true;
    }
    else if (Priority != theOther.Priority)
    {
      return false;
    }

    //if (Abs (Depth - theOther.Depth) <= (Tolerance + theOther.Tolerance))
    if (Abs (Depth - theOther.Depth) <= Precision::Confusion())
    {
      return MinDist < theOther.MinDist;
    }

    return Depth < theOther.Depth;
  }

};

#endif // _SelectMgr_SortCriterion_HeaderFile
