// Created on: 1995-07-07
// Created by: Joelle CHAUVET
// Copyright (c) 1995-1999 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.

// Modified : 08/07/97 : JPI : traitement des edges degeneres comme pour les fillets 2D
// Modified:	Fri Sep 25 09:38:04 1998
//              status = ChFi2d_NotAuthorized si les aretes ne sont pas
//              des droites ou des cercles; fonction IsLineOrCircle
//              (BUC60288)

#include <BRep_Builder.hxx>
#include <BRep_Tool.hxx>
#include <BRepAdaptor_Curve.hxx>
#include <BRepAdaptor_Surface.hxx>
#include <BRepLib_MakeEdge.hxx>
#include <BRepLib_MakeFace.hxx>
#include <ChFi2d.hxx>
#include <ChFi2d_Builder.hxx>
#include <ElCLib.hxx>
#include <GCPnts_AbscissaPoint.hxx>
#include <Geom2d_Circle.hxx>
#include <Geom2d_Curve.hxx>
#include <Geom2d_Line.hxx>
#include <Geom2d_TrimmedCurve.hxx>
#include <Geom2dAdaptor_Curve.hxx>
#include <Geom2dInt_GInter.hxx>
#include <Geom_Curve.hxx>
#include <Geom_Line.hxx>
#include <Geom_Plane.hxx>
#include <Geom_Surface.hxx>
#include <GeomAdaptor_Curve.hxx>
#include <GeomAPI.hxx>
#include <gp_Pln.hxx>
#include <gp_Pnt.hxx>
#include <gp_Pnt2d.hxx>
#include <IntRes2d_IntersectionPoint.hxx>
#include <Precision.hxx>
#include <TopAbs_Orientation.hxx>
#include <TopExp.hxx>
#include <TopExp_Explorer.hxx>
#include <TopLoc_Location.hxx>
#include <TopoDS.hxx>
#include <TopoDS_Edge.hxx>
#include <TopoDS_Face.hxx>
#include <TopoDS_Shape.hxx>
#include <TopoDS_Vertex.hxx>
#include <TopoDS_Wire.hxx>

gp_Pnt ComputePoint(const TopoDS_Vertex& V,const TopoDS_Edge& E, 
		    const Standard_Real D1, Standard_Real& Param1);
gp_Pnt ComputePoint(const TopoDS_Face& F, const Handle(Geom_Line)& L,
		    const TopoDS_Edge& E, Standard_Real& Param);
void OrientChamfer(TopoDS_Edge& chamfer,
		   const TopoDS_Edge& E,
		   const TopoDS_Vertex& V);

static Standard_Boolean IsLineOrCircle(const TopoDS_Edge& E,
				       const TopoDS_Face& F);


//=======================================================================
//function : AddChamfer
//purpose  : 
//=======================================================================

TopoDS_Edge ChFi2d_Builder::AddChamfer(const TopoDS_Edge& E1,
				     const TopoDS_Edge& E2,
				     const Standard_Real D1,
				     const Standard_Real D2)
{
  TopoDS_Vertex commonVertex;
  TopoDS_Edge basisEdge1, basisEdge2;
  TopoDS_Edge E1Mod, E2Mod, chamfer;
  
  Standard_Boolean hasConnection = ChFi2d::CommonVertex(E1, E2, commonVertex);
  if (!hasConnection) return chamfer;

  if (IsAFillet(E1) || IsAChamfer(E1) ||
      IsAFillet(E2) || IsAChamfer(E2)) {
    status = ChFi2d_NotAuthorized;
    return chamfer;
  } //  if (IsAChamfer ...

  if (!IsLineOrCircle(E1,newFace) 
      || !IsLineOrCircle(E2,newFace) ) {
    status = ChFi2d_NotAuthorized;
    return chamfer;
  } //  if (!IsLineOrCircle ...

  // EE1 and EE2 are copies of E1 and E2 with the good orientation
  // on <newFace>
  TopoDS_Edge EE1, EE2;
  status = ChFi2d::FindConnectedEdges(newFace, commonVertex, EE1, EE2);
  if (EE1.IsSame(E2)) {
    TopAbs_Orientation orient = EE1.Orientation();
    EE1 = EE2;
    EE2 = E2;
    EE2.Orientation(orient);
  }

  ComputeChamfer(commonVertex, EE1, EE2, D1, D2,
		 E1Mod, E2Mod, chamfer);
  if (status == ChFi2d_IsDone
      || status == ChFi2d_FirstEdgeDegenerated
      || status == ChFi2d_LastEdgeDegenerated
      || status == ChFi2d_BothEdgesDegenerated) {
//  if (status == ChFi2d_IsDone) {
    BuildNewWire(EE1, EE2, E1Mod, chamfer, E2Mod);
    basisEdge1 = BasisEdge(EE1);
    basisEdge2 = BasisEdge(EE2);
    UpDateHistory(basisEdge1, basisEdge2,
		  E1Mod, E2Mod, chamfer, 2);
    status = ChFi2d_IsDone;
    return TopoDS::Edge(chamfers.Value(chamfers.Length()));
  }
  return chamfer;
} // AddChamfer


//=======================================================================
//function : AddChamfer
//purpose  : 
//=======================================================================

TopoDS_Edge ChFi2d_Builder::AddChamfer(const TopoDS_Edge& E,
				     const TopoDS_Vertex& V,
				     const Standard_Real D,
				     const Standard_Real Ang)
{
  TopoDS_Edge aChamfer, adjEdge1, adjEdge2;
  status = ChFi2d::FindConnectedEdges(newFace, V, adjEdge1, adjEdge2);
  if (status == ChFi2d_ConnexionError) return aChamfer;

  // adjEdge1 is a copy of E  with the good orientation
  // on <newFace>
  if (adjEdge2.IsSame(E)) {
    TopAbs_Orientation orient = adjEdge2.Orientation();
    adjEdge2 = adjEdge1;
    adjEdge1 = E;
    adjEdge1.Orientation(orient);
  }

  if (IsAFillet(adjEdge1) || IsAChamfer(adjEdge1) ||
      IsAFillet(adjEdge2) || IsAChamfer(adjEdge2)) {
    status = ChFi2d_NotAuthorized;
    return aChamfer;
  } //  if (IsAChamfer ...

  if (!IsLineOrCircle(adjEdge1,newFace) 
      || !IsLineOrCircle(adjEdge2,newFace) ) {
    status = ChFi2d_NotAuthorized;
    return aChamfer;
  } //  if (!IsLineOrCircle ...

  TopoDS_Edge E1, E2;
  ComputeChamfer(V, adjEdge1, D, Ang,
		 adjEdge2, E1, E2, aChamfer);
  TopoDS_Edge basisEdge1, basisEdge2;
  if (status == ChFi2d_IsDone
      || status == ChFi2d_FirstEdgeDegenerated
      || status == ChFi2d_LastEdgeDegenerated
      || status == ChFi2d_BothEdgesDegenerated) {
//  if (status == ChFi2d_IsDone) {
    BuildNewWire(adjEdge1, adjEdge2, E1, aChamfer, E2);
    basisEdge1 = BasisEdge(adjEdge1);
    basisEdge2 = BasisEdge(adjEdge2);
    UpDateHistory(basisEdge1, basisEdge2,
		  E1, E2, aChamfer, 2);
    status = ChFi2d_IsDone;
    return TopoDS::Edge(chamfers.Value(chamfers.Length()));
  }
  return aChamfer;

}


//=======================================================================
//function : ComputeChamfer
//purpose  : 
//=======================================================================

void ChFi2d_Builder::ComputeChamfer(const TopoDS_Vertex& V, 
				  const TopoDS_Edge& E1, 
				  const TopoDS_Edge& E2, 
				  const Standard_Real D1,
				  const Standard_Real D2,
				  TopoDS_Edge& TrimE1, 
				  TopoDS_Edge& TrimE2, 
				  TopoDS_Edge& Chamfer) 
{
   TopoDS_Vertex newExtr1, newExtr2;
   Standard_Boolean Degen1, Degen2;
   Chamfer = BuildChamferEdge(V, E1, E2, D1, D2, newExtr1, newExtr2);
   if ( status != ChFi2d_IsDone) return;
  TrimE1 = BuildNewEdge(E1, V, newExtr1, Degen1);
  TrimE2 = BuildNewEdge(E2, V, newExtr2, Degen2);
  if (Degen1 && Degen2 ) status = ChFi2d_BothEdgesDegenerated;
  if (Degen1 && !Degen2 ) status = ChFi2d_FirstEdgeDegenerated;
  if (!Degen1 && Degen2 ) status = ChFi2d_LastEdgeDegenerated;
//   TrimE1 = BuildNewEdge(E1, V, newExtr1);
//  TrimE2 = BuildNewEdge(E2, V, newExtr2);
} // ComputeChamfer


//=======================================================================
//function : ComputeChamfer
//purpose  : 
//=======================================================================

void ChFi2d_Builder::ComputeChamfer(const TopoDS_Vertex& V, 
				  const TopoDS_Edge& E1, 
				  const Standard_Real D,
				  const Standard_Real Ang,
				  const TopoDS_Edge& E2, 
				  TopoDS_Edge& TrimE1, 
				  TopoDS_Edge& TrimE2, 
				  TopoDS_Edge& Chamfer) 
{
   TopoDS_Vertex newExtr1, newExtr2;
   Standard_Boolean Degen1, Degen2;
   Chamfer = BuildChamferEdge(V, E1, D, Ang, E2, newExtr1, newExtr2);
   if ( status != ChFi2d_IsDone) return;
  TrimE1 = BuildNewEdge(E1, V, newExtr1, Degen1);
  TrimE2 = BuildNewEdge(E2, V, newExtr2, Degen2);
  if (Degen1 && Degen2 ) status = ChFi2d_BothEdgesDegenerated;
  if (Degen1 && !Degen2 ) status = ChFi2d_FirstEdgeDegenerated;
  if (!Degen1 && Degen2 ) status = ChFi2d_LastEdgeDegenerated;
//   TrimE1 = BuildNewEdge(E1, V, newExtr1);
//   TrimE2 = BuildNewEdge(E2, V, newExtr2);
} // ComputeChamfer


//=======================================================================
//function : ModifyFillet
//purpose  : 
//=======================================================================

TopoDS_Edge ChFi2d_Builder::ModifyChamfer(const TopoDS_Edge& Chamfer, 
					const TopoDS_Edge& /*E1*/, 
					const TopoDS_Edge& E2,  
					const Standard_Real D1,
					const Standard_Real D2)
{
  TopoDS_Vertex aVertex = RemoveChamfer(Chamfer);
  TopoDS_Edge adjEdge1, adjEdge2;
  status = ChFi2d::FindConnectedEdges(newFace, aVertex, adjEdge1, adjEdge2);
  TopoDS_Edge aChamfer;
  if (status == ChFi2d_ConnexionError) return aChamfer;

  // adjEdge1 and adjEdge2 are copies of E1 and E2 with the good orientation
  // on <newFace>
  if (adjEdge1.IsSame(E2)) {
    TopAbs_Orientation orient = adjEdge1.Orientation();
    adjEdge1 = adjEdge2;
    adjEdge2 = E2;
    adjEdge2.Orientation(orient);
  }

  aChamfer = AddChamfer(adjEdge1, adjEdge2, D1, D2);
  return aChamfer;
} // ModifyChamfer


//=======================================================================
//function : ModifyFillet
//purpose  : 
//=======================================================================

TopoDS_Edge ChFi2d_Builder::ModifyChamfer(const TopoDS_Edge& Chamfer, 
					const TopoDS_Edge& E, 
					const Standard_Real D,
					const Standard_Real Ang)
{
  TopoDS_Vertex aVertex = RemoveChamfer(Chamfer);
  TopoDS_Edge adjEdge1, adjEdge2;
  status = ChFi2d::FindConnectedEdges(newFace, aVertex, adjEdge1, adjEdge2);
  TopoDS_Edge aChamfer;
  if (status == ChFi2d_ConnexionError) return aChamfer;

  if (adjEdge1.IsSame(E)) 
    aChamfer = AddChamfer(adjEdge1, aVertex, D, Ang);
  else aChamfer = AddChamfer(adjEdge2, aVertex, D, Ang);
  return aChamfer;
} // ModifyChamfer


//=======================================================================
//function : RemoveChamfer
//purpose  : 
//=======================================================================

TopoDS_Vertex ChFi2d_Builder::RemoveChamfer(const TopoDS_Edge& Chamfer)
{
  TopoDS_Vertex commonVertex;

  Standard_Integer i = 1;
  Standard_Integer IsFind = Standard_False;
  while (i <= chamfers.Length()) {
    const TopoDS_Edge& aChamfer = TopoDS::Edge(chamfers.Value(i));
    if (aChamfer.IsSame(Chamfer)) {
      chamfers.Remove(i);
      IsFind = Standard_True;
      break;
    }
    i++;
  }
  if (!IsFind) return commonVertex;

  TopoDS_Vertex firstVertex, lastVertex;
  TopExp::Vertices(Chamfer, firstVertex, lastVertex);


  TopoDS_Edge adjEdge1, adjEdge2;
  status = ChFi2d::FindConnectedEdges(newFace, firstVertex,
				     adjEdge1, adjEdge2);
  if (status == ChFi2d_ConnexionError) return commonVertex;

  TopoDS_Edge basisEdge1, basisEdge2, E1, E2;
  // E1 and E2 are the adjacentes edges to Chamfer

  if (adjEdge1.IsSame(Chamfer)) E1 = adjEdge2;
  else E1 = adjEdge1;
  basisEdge1 = BasisEdge(E1);
  status = ChFi2d::FindConnectedEdges(newFace, lastVertex,adjEdge1, adjEdge2);
  if (status == ChFi2d_ConnexionError) return commonVertex;
  if (adjEdge1.IsSame(Chamfer)) E2 = adjEdge2;
  else E2 = adjEdge1;
  basisEdge2 = BasisEdge(E2);
  TopoDS_Vertex connectionE1Chamfer, connectionE2Chamfer;
  Standard_Boolean hasConnection = 
    ChFi2d::CommonVertex(basisEdge1, basisEdge2, commonVertex);
  if (!hasConnection) {
    status = ChFi2d_ConnexionError;
    return commonVertex;
  }
  hasConnection = ChFi2d::CommonVertex(E1, Chamfer, connectionE1Chamfer);
  if (!hasConnection) {
    status = ChFi2d_ConnexionError;
    return commonVertex;
  }
  hasConnection = ChFi2d::CommonVertex(E2, Chamfer, connectionE2Chamfer);
  if (!hasConnection) {
    status = ChFi2d_ConnexionError;
    return commonVertex;
  }

  // rebuild edges on wire
  TopoDS_Edge newEdge1, newEdge2;
  TopoDS_Vertex v, v1, v2;
  BRepLib_MakeEdge makeEdge;
  TopLoc_Location loc;
  Standard_Real first, last;

  TopExp::Vertices(E1, firstVertex, lastVertex);
  TopExp::Vertices(basisEdge1, v1, v2);
  if (v1.IsSame(commonVertex)) v = v2;
  else v = v1;

  if ( firstVertex.IsSame(v) || lastVertex.IsSame(v)) 
    // It means the edge support only one fillet. In this case
    // the new edge must be the basis edge.
    newEdge1 = basisEdge1;
  else {
    // It means the edge support one fillet on each end.
    if (firstVertex.IsSame(connectionE1Chamfer)) {
//  syntaxe invalide sur NT
//      const Handle(Geom_Curve)& curve = 
//	BRep_Tool::Curve(E1, loc, first, last);   
      Handle(Geom_Curve) curve = BRep_Tool::Curve(E1, loc, first, last);
      makeEdge.Init(curve, commonVertex, lastVertex);  
      newEdge1 = makeEdge.Edge();
      newEdge1.Orientation(basisEdge1.Orientation());
      newEdge1.Location(basisEdge1.Location());
    } // if (firstVertex ...
    else if (lastVertex.IsSame(connectionE1Chamfer)) { 
//  syntaxe invalide sur NT
//      const Handle(Geom_Curve)& curve = 
//	BRep_Tool::Curve(E1, loc, first, last);   
      Handle(Geom_Curve) curve = BRep_Tool::Curve(E1, loc, first, last);
      makeEdge.Init(curve, firstVertex, commonVertex);
      newEdge1 = makeEdge.Edge();
      newEdge1.Orientation(basisEdge1.Orientation());
      newEdge1.Location(basisEdge1.Location());
    } // else if (lastVertex ...
  } // else ...

  TopExp::Vertices(basisEdge2, v1, v2);
  if (v1.IsSame(commonVertex)) v = v2;
  else v = v1;

  TopExp::Vertices(E2, firstVertex, lastVertex);   
  if ( firstVertex.IsSame(v) || lastVertex.IsSame(v)) 
    // It means the edge support only one fillet. In this case
    // the new edge must be the basis edge.
    newEdge2 = basisEdge2;
  else {
    // It means the edge support one fillet on each end.
    if (firstVertex.IsSame(connectionE2Chamfer)) {
//  syntaxe invalide sur NT
//      const Handle(Geom_Curve)& curve = 
//	BRep_Tool::Curve(E2, loc, first, last);   
      Handle(Geom_Curve) curve = BRep_Tool::Curve(E2, loc, first, last);
      makeEdge.Init(curve, commonVertex, lastVertex);
      newEdge2 = makeEdge.Edge();
      newEdge2.Orientation(basisEdge2.Orientation());
      newEdge2.Location(basisEdge2.Location());
    } // if (firstVertex ...
    else if (lastVertex.IsSame(connectionE2Chamfer)) {
//  syntaxe invalide sur NT
//      const Handle(Geom_Curve)& curve = 
//	BRep_Tool::Curve(E2, loc, first, last);   
      Handle(Geom_Curve) curve = BRep_Tool::Curve(E2, loc, first, last);
      makeEdge.Init(curve, firstVertex, commonVertex);
      newEdge2 = makeEdge.Edge();
      newEdge2.Orientation(basisEdge2.Orientation());
      newEdge2.Location(basisEdge2.Location());
    } // else if (lastVertex ... 
  } // else ...

  // rebuild the newFace
  TopExp_Explorer Ex(newFace, TopAbs_EDGE);
  TopoDS_Wire newWire;

  BRep_Builder B;
  B.MakeWire(newWire);

  while (Ex.More()) {
    const TopoDS_Edge& theEdge = TopoDS::Edge(Ex.Current());
    if (!theEdge.IsSame(E1) && 
	!theEdge.IsSame(E2) && 
	!theEdge.IsSame(Chamfer) )
      B.Add(newWire, theEdge);
    else {
      if (theEdge == E1) 
	B.Add(newWire, newEdge1);
      else if (theEdge == E2)
	B.Add(newWire, newEdge2);
    } // else
    Ex.Next();
  } // while ...

  BRepAdaptor_Surface Adaptor3dSurface(refFace);
  BRepLib_MakeFace mFace(Adaptor3dSurface.Plane(), newWire);
  newFace.Nullify();
  newFace = mFace;

  UpDateHistory(basisEdge1, basisEdge2, newEdge1, newEdge2);  

  return commonVertex;
} // RemoveChamfer


//=======================================================================
//function : BuildChamferEdge
//purpose  : 
//=======================================================================
TopoDS_Edge ChFi2d_Builder::BuildChamferEdge(const TopoDS_Vertex& V, 
					   const TopoDS_Edge& AdjEdge1, 
					   const TopoDS_Edge& AdjEdge2, 
					   const Standard_Real D1,
					   const Standard_Real D2,
					   TopoDS_Vertex& NewExtr1,
					   TopoDS_Vertex& NewExtr2)
{
  TopoDS_Edge chamfer;
  if ( D1 <= 0 || D2 <= 0) {
    status = ChFi2d_ParametersError;
    return chamfer;
  } // if ( D1 <=0 ...
  
  Standard_Real param1, param2;
  gp_Pnt p1 = ComputePoint(V, AdjEdge1, D1, param1);
  gp_Pnt p2 = ComputePoint(V, AdjEdge2, D2, param2);
  
  Standard_Real tol = Precision::Confusion();
  BRep_Builder B;
  B.MakeVertex(NewExtr1, p1, tol);
  B.MakeVertex(NewExtr2, p2, tol);
  NewExtr1.Orientation(TopAbs_FORWARD);
  NewExtr2.Orientation(TopAbs_REVERSED);

  // chamfer edge construction
  TopLoc_Location loc;
  const Handle(Geom_Surface) refSurf = BRep_Tool::Surface(refFace, loc);
  gp_Vec myVec( p1, p2);
  gp_Dir myDir(myVec);
  Handle(Geom_Line) newLine = new Geom_Line( p1, myDir);
  Standard_Real param = ElCLib::Parameter(newLine->Lin(), p2);
  B.MakeEdge(chamfer, newLine, tol);
  B.Range(chamfer,0., param);
  B.Add(chamfer, NewExtr1);
  B.UpdateVertex(NewExtr1,0., chamfer, tol);
  B.Add(chamfer, NewExtr2);
  B.UpdateVertex(NewExtr2,param, chamfer, tol);
  OrientChamfer(chamfer, AdjEdge1, V);

  // set the orientation of NewExtr1 and NewExtr2 for the adjacent edges
  TopoDS_Vertex V1 = TopExp::FirstVertex(AdjEdge1);
  TopoDS_Vertex V2 = TopExp::LastVertex(AdjEdge1);
  if (V1.IsSame(V)) NewExtr1.Orientation(V1.Orientation());
  else NewExtr1.Orientation(V2.Orientation());

  V1 = TopExp::FirstVertex(AdjEdge2);
  V2 = TopExp::LastVertex(AdjEdge2);
  if (V1.IsSame(V)) NewExtr2.Orientation(V1.Orientation());
  else NewExtr2.Orientation(V2.Orientation());
  B.UpdateVertex(NewExtr1, param1, AdjEdge1, tol);
  B.UpdateVertex(NewExtr2, param2, AdjEdge2, tol);

  status = ChFi2d_IsDone;
  return chamfer;
} // BuildChamferEdge


//=======================================================================
//function : BuildFilletEdge
//purpose  : 
//=======================================================================
TopoDS_Edge ChFi2d_Builder::BuildChamferEdge(const TopoDS_Vertex& V, 
					   const TopoDS_Edge& AdjEdge1, 
					   const Standard_Real D,
					   const Standard_Real Ang,
					   const TopoDS_Edge& AdjEdge2, 
					   TopoDS_Vertex& NewExtr1,
					   TopoDS_Vertex& NewExtr2)
{
  TopoDS_Edge chamfer;
  if ( D <= 0 || Ang <= 0) {
    status = ChFi2d_ParametersError;
    return chamfer;
  } // if ( D <= 0 ...

  Standard_Real param1, param2;
  gp_Pnt p1 = ComputePoint(V, AdjEdge1, D, param1);
  gp_Pnt p = BRep_Tool::Pnt(V);
  gp_Vec myVec( p1, p);

  // compute the tangent vector on AdjEdge2 at the vertex V.
  BRepAdaptor_Curve c(AdjEdge2, refFace);
  Standard_Real first, last;
  first = c.FirstParameter();
  last = c.LastParameter();

  gp_Pnt aPoint;
  gp_Vec tan;
  c.D1(first, aPoint, tan);
  if (aPoint.Distance(p) > Precision::Confusion()) {
    c.D1(last, aPoint, tan);
  }
  // tangent orientation
  TopoDS_Vertex v1, v2;
  TopExp::Vertices(AdjEdge2, v1, v2);
  TopAbs_Orientation orient;
  if (v1.IsSame(V)) orient = v1.Orientation();
  else orient = v2.Orientation();
  if (orient == TopAbs_REVERSED) tan *= -1;

  // compute the chamfer geometric support 
  gp_Ax1 RotAxe(p1, tan^myVec);
  gp_Vec vecLin = myVec.Rotated(RotAxe, -Ang);
  gp_Dir myDir(vecLin);
  Handle(Geom_Line) newLine = new Geom_Line( p1, myDir);
  BRep_Builder B1;
  B1.MakeEdge(chamfer, newLine, Precision::Confusion());
  gp_Pnt p2 = ComputePoint(refFace, newLine, AdjEdge2, param2);


  Standard_Real tol = Precision::Confusion();
  BRep_Builder B;
  B.MakeVertex(NewExtr1, p1, tol);
  B.MakeVertex(NewExtr2, p2, tol);
  NewExtr1.Orientation(TopAbs_FORWARD);
  NewExtr2.Orientation(TopAbs_REVERSED);

  // chamfer edge construction
  Standard_Real param = ElCLib::Parameter(newLine->Lin(), p2);
  B.MakeEdge(chamfer, newLine, tol);
  B.Range(chamfer,0., param);
  B.Add(chamfer, NewExtr1);
  B.UpdateVertex(NewExtr1,0., chamfer, tol);
  B.Add(chamfer, NewExtr2);
  B.UpdateVertex(NewExtr2,param, chamfer, tol);
  OrientChamfer(chamfer, AdjEdge1, V);

  // set the orientation of NewExtr1 and NewExtr2 for the adjacent edges
  TopoDS_Vertex V1 = TopExp::FirstVertex(AdjEdge1);
  TopoDS_Vertex V2 = TopExp::LastVertex(AdjEdge1);
  if (V1.IsSame(V)) NewExtr1.Orientation(V1.Orientation());
  else NewExtr1.Orientation(V2.Orientation());

  V1 = TopExp::FirstVertex(AdjEdge2);
  V2 = TopExp::LastVertex(AdjEdge2);
  if (V1.IsSame(V)) NewExtr2.Orientation(V1.Orientation());
  else NewExtr2.Orientation(V2.Orientation());
  B.UpdateVertex(NewExtr1, param1, AdjEdge1, tol);
  B.UpdateVertex(NewExtr2, param2, AdjEdge2, tol);

  status = ChFi2d_IsDone;
  return chamfer;
}


//=======================================================================
//function : ComputePoint
//purpose  : 
//=======================================================================

gp_Pnt ComputePoint(const TopoDS_Vertex& V,const TopoDS_Edge& E, 
		    const Standard_Real D, Standard_Real& Param)
{
  // geometric support
  BRepAdaptor_Curve c(E);
  Standard_Real first, last;
  first = c.FirstParameter();
  last = c.LastParameter();

  gp_Pnt thePoint;
  if (c.GetType() == GeomAbs_Line) {
    gp_Pnt p1, p2;
    TopoDS_Vertex v1, v2;
    TopExp::Vertices(E, v1, v2);
    p1 = BRep_Tool::Pnt(v1);
    p2 = BRep_Tool::Pnt(v2);
    gp_Vec myVec( p1, p2);
    myVec.Normalize();
    myVec *= D;
    if (v2.IsSame(V)) {
      myVec *= -1; // change the sense of myVec
      thePoint = p2.Translated(myVec);
    } // if (v2 ...
    else thePoint = p1.Translated(myVec);

    Param = ElCLib::Parameter(c.Line(), thePoint);
	//szv:OCC20823-begin
    c.D0(Param, thePoint);
	//szv:OCC20823-end
    return thePoint;
  } // if (C->IsKind(TYPE ...

  if (c.GetType() == GeomAbs_Circle) {
    gp_Circ cir = c.Circle();
    Standard_Real radius = cir.Radius();
    TopoDS_Vertex v1, v2;
    TopExp::Vertices(E, v1, v2);
    Standard_Real param1,param2;
    if (V.IsSame(v1)) {
      param1 = BRep_Tool::Parameter(v1,E);
      param2 = BRep_Tool::Parameter(v2,E);
    }
    else {
      param1 = BRep_Tool::Parameter(v2,E);
      param2 = BRep_Tool::Parameter(v1,E);
    }     
    Standard_Real deltaAlpha = D/radius;
    if (param1 > param2) Param = param1 - deltaAlpha;
    else Param = param1 + deltaAlpha;
    c.D0(Param, thePoint);
    return thePoint;
  } // if (C->IsKind(TYPE ...  

  else {
    // in all other case than lines and circles.
    gp_Pnt p;
    TopoDS_Vertex v1, v2;
    TopExp::Vertices(E, v1, v2);
    if (V.IsSame(v1)) {
      p = BRep_Tool::Pnt(v1);
    }
    else {
      p = BRep_Tool::Pnt(v2);
    }     

    GeomAdaptor_Curve cc = c.Curve();
    if (p.Distance(c.Value(first)) <= Precision::Confusion()) {
      GCPnts_AbscissaPoint computePoint(cc, D, first);
      Param = computePoint.Parameter();
    }
    else {
      GCPnts_AbscissaPoint computePoint(cc, D, last);
      Param = computePoint.Parameter();
    }
    thePoint = cc.Value(Param);
    return thePoint;
  } // else ...
} // ComputePoint



//=======================================================================
//function : ComputePoint
//purpose  : 
//=======================================================================

gp_Pnt ComputePoint(const TopoDS_Face& F, 
		    const Handle(Geom_Line)& L,
		    const TopoDS_Edge& E, 
		    Standard_Real& Param)
{
  BRepAdaptor_Surface Adaptor3dSurface(F);
  Handle(Geom_Plane) refSurf = new Geom_Plane(Adaptor3dSurface.Plane());
  Handle(Geom2d_Curve) lin2d = GeomAPI::To2d(L, refSurf->Pln());
  Handle(Geom2d_Curve) c2d;
  Standard_Real first, last;
  c2d = BRep_Tool::CurveOnSurface(E, F, first, last);
  Geom2dAdaptor_Curve adaptorL(lin2d);
  Geom2dAdaptor_Curve adaptorC(c2d);
  Geom2dInt_GInter Intersection(adaptorL, adaptorC,
				Precision::PIntersection(),
				Precision::PIntersection());
  Standard_Real paramOnLine = 1E300;
  gp_Pnt2d p2d;
  if (Intersection.IsDone()) {
    Standard_Integer i = 1;
    while ( i <= Intersection.NbPoints()) {
      IntRes2d_IntersectionPoint iP = Intersection.Point(i);
      if (iP.ParamOnFirst() < paramOnLine) {
	p2d = iP.Value();
	paramOnLine = iP.ParamOnFirst();
	Param = iP.ParamOnSecond();
      } // if (iP.ParamOnFirst ...
      i++;
    } // while ( i <= ... 
  } // if (Intersection.IsDone ...

  gp_Pnt thePoint = Adaptor3dSurface.Value(p2d.X(), p2d.Y());  
  return thePoint;
} // ComputePoint

//=======================================================================
//function : OrientChamfer
//purpose  : 
//=======================================================================

void OrientChamfer(TopoDS_Edge& chamfer,
		   const TopoDS_Edge& E,
		   const TopoDS_Vertex& V)
{ 
  TopAbs_Orientation vOrient, orient = E.Orientation();
  TopoDS_Vertex v1, v2;
  TopExp::Vertices(E, v1, v2);
  if (v1.IsSame(V)) vOrient = v2.Orientation();
  else vOrient = v1.Orientation();

  if ((orient == TopAbs_FORWARD && vOrient == TopAbs_FORWARD) ||
      (orient == TopAbs_REVERSED && vOrient == TopAbs_REVERSED))
    chamfer.Orientation(TopAbs_FORWARD);
  else chamfer.Orientation(TopAbs_REVERSED);
} // OrientChamfer


//=======================================================================
//function : IsLineOrCircle
//purpose  : 
//=======================================================================

Standard_Boolean IsLineOrCircle(const TopoDS_Edge& E,
				const TopoDS_Face& F) 
{
  Standard_Real first, last;
  TopLoc_Location loc;
//  syntaxe invalide sur NT
//      const Handle(Geom2d_Curve)& C = 
//	BRep_Tool::CurveOnSurface(E,F,first,last);   
  Handle(Geom2d_Curve) C = BRep_Tool::CurveOnSurface(E,F,first,last);
  Handle(Geom2d_Curve) basisC; 
  Handle(Geom2d_TrimmedCurve) TC = Handle(Geom2d_TrimmedCurve)::DownCast(C);
  if (!TC.IsNull())
    basisC = TC->BasisCurve();
  else
    basisC = C;

  if ( basisC->DynamicType() == STANDARD_TYPE(Geom2d_Circle)
      || basisC->DynamicType() == STANDARD_TYPE(Geom2d_Line) ) {
    return Standard_True;
  }
  else {
    return Standard_False;
  } // else ...
} // IsLineOrCircle