//=======================================================================
//function : GlueEdgesWithPCurves
//purpose  : Glues the pcurves of the sequence of edges
//           and glues their 3d curves
//=======================================================================
static TopoDS_Edge GlueEdgesWithPCurves(const TopTools_SequenceOfShape& aChain,
                                        const TopoDS_Vertex& FirstVertex,
                                        const TopoDS_Vertex& LastVertex)
{
  Standard_Integer i, j;

  TopoDS_Edge FirstEdge = TopoDS::Edge(aChain(1));
  //TColGeom2d_SequenceOfCurve PCurveSeq;
  TColGeom_SequenceOfSurface SurfSeq;
  //TopTools_SequenceOfShape LocSeq;
  
  BRep_ListIteratorOfListOfCurveRepresentation itr( (Handle(BRep_TEdge)::DownCast(FirstEdge.TShape()))->Curves() );
  for (; itr.More(); itr.Next())
  {
    Handle(BRep_CurveRepresentation) CurveRep = itr.Value();
    if (CurveRep->IsCurveOnSurface())
    {
      //PCurveSeq.Append(CurveRep->PCurve());
      SurfSeq.Append(CurveRep->Surface());
      /*
      TopoDS_Shape aLocShape;
      aLocShape.Location(CurveRep->Location());
      LocSeq.Append(aLocShape);
      */
    }
  }

  Standard_Real fpar, lpar;
  BRep_Tool::Range(FirstEdge, fpar, lpar);
  TopoDS_Edge PrevEdge = FirstEdge;
  TopoDS_Vertex CV;
  Standard_Real MaxTol = 0.;
  
  TopoDS_Edge ResEdge;
  BRep_Builder BB;

  Standard_Integer nb_curve = aChain.Length();   //number of curves
  TColGeom_Array1OfBSplineCurve tab_c3d(0,nb_curve-1);                    //array of the curves
  TColStd_Array1OfReal tabtolvertex(0,nb_curve-1); //(0,nb_curve-2);  //array of the tolerances
    
  TopoDS_Vertex PrevVertex = FirstVertex;
  for (i = 1; i <= nb_curve; i++)
  {
    TopoDS_Edge anEdge = TopoDS::Edge(aChain(i));
    TopoDS_Vertex VF, VL;
    TopExp::Vertices(anEdge, VF, VL);
    Standard_Boolean ToReverse = (!VF.IsSame(PrevVertex));
    
    Standard_Real Tol1 = BRep_Tool::Tolerance(VF);
    Standard_Real Tol2 = BRep_Tool::Tolerance(VL);
    if (Tol1 > MaxTol)
      MaxTol = Tol1;
    if (Tol2 > MaxTol)
      MaxTol = Tol2;
    
    if (i > 1)
    {
      TopExp::CommonVertex(PrevEdge, anEdge, CV);
      Standard_Real Tol = BRep_Tool::Tolerance(CV);
      tabtolvertex(i-2) = Tol;
    }
    
    Handle(Geom_Curve) aCurve = BRep_Tool::Curve(anEdge, fpar, lpar);
    Handle(Geom_TrimmedCurve) aTrCurve = new Geom_TrimmedCurve(aCurve, fpar, lpar);
    tab_c3d(i-1) = GeomConvert::CurveToBSplineCurve(aTrCurve);
    GeomConvert::C0BSplineToC1BSplineCurve(tab_c3d(i-1), Precision::Confusion());
    if (ToReverse)
      tab_c3d(i-1)->Reverse();
    PrevVertex = (ToReverse)? VF : VL;
    PrevEdge = anEdge;
  }
  Handle(TColGeom_HArray1OfBSplineCurve)  concatcurve;     //array of the concatenated curves
  Handle(TColStd_HArray1OfInteger)        ArrayOfIndices;  //array of the remining Vertex
  GeomConvert::ConcatC1(tab_c3d,
                        tabtolvertex,
                        ArrayOfIndices,
                        concatcurve,
                        Standard_False,
                        Precision::Confusion());   //C1 concatenation
  
  if (concatcurve->Length() > 1)
  {
    GeomConvert_CompCurveToBSplineCurve Concat(concatcurve->Value(concatcurve->Lower()));
    
    for (i = concatcurve->Lower()+1; i <= concatcurve->Upper(); i++)
      Concat.Add( concatcurve->Value(i), MaxTol, Standard_True );
    
    concatcurve->SetValue(concatcurve->Lower(), Concat.BSplineCurve());
  }
  Handle(Geom_BSplineCurve) ResCurve = concatcurve->Value(concatcurve->Lower());
  
  TColGeom2d_SequenceOfBoundedCurve ResPCurves;
  TopLoc_Location aLoc;
  for (j = 1; j <= SurfSeq.Length(); j++)
  {
    TColGeom2d_Array1OfBSplineCurve tab_c2d(0,nb_curve-1); //array of the pcurves
    
    PrevVertex = FirstVertex;
    PrevEdge = FirstEdge;
    //TopLoc_Location theLoc = LocSeq(j).Location();
    for (i = 1; i <= nb_curve; i++)
    {
      TopoDS_Edge anEdge = TopoDS::Edge(aChain(i));
      TopoDS_Vertex VF, VL;
      TopExp::Vertices(anEdge, VF, VL);
      Standard_Boolean ToReverse = (!VF.IsSame(PrevVertex));

      /*
      Handle(Geom2d_Curve) aPCurve =
        BRep_Tool::CurveOnSurface(anEdge, SurfSeq(j), anEdge.Location()*theLoc, fpar, lpar);
      */
      Handle(Geom2d_Curve) aPCurve =
        BRep_Tool::CurveOnSurface(anEdge, SurfSeq(j), aLoc, fpar, lpar);
      Handle(Geom2d_TrimmedCurve) aTrPCurve = new Geom2d_TrimmedCurve(aPCurve, fpar, lpar);
      tab_c2d(i-1) = Geom2dConvert::CurveToBSplineCurve(aTrPCurve);
      Geom2dConvert::C0BSplineToC1BSplineCurve(tab_c2d(i-1), Precision::Confusion());
      if (ToReverse)
        tab_c2d(i-1)->Reverse();
      PrevVertex = (ToReverse)? VF : VL;
      PrevEdge = anEdge;
    }
    Handle(TColGeom2d_HArray1OfBSplineCurve)  concatc2d;     //array of the concatenated curves
    Handle(TColStd_HArray1OfInteger)        ArrayOfInd2d;  //array of the remining Vertex
    Geom2dConvert::ConcatC1(tab_c2d,
                            tabtolvertex,
                            ArrayOfInd2d,
                            concatc2d,
                            Standard_False,
                            Precision::Confusion());   //C1 concatenation
    
    if (concatc2d->Length() > 1)
    {
      Geom2dConvert_CompCurveToBSplineCurve Concat2d(concatc2d->Value(concatc2d->Lower()));
      
      for (i = concatc2d->Lower()+1; i <= concatc2d->Upper(); i++)
        Concat2d.Add( concatc2d->Value(i), MaxTol, Standard_True );
      
      concatc2d->SetValue(concatc2d->Lower(), Concat2d.BSplineCurve());
    }
    Handle(Geom2d_BSplineCurve) aResPCurve = concatc2d->Value(concatc2d->Lower());
    ResPCurves.Append(aResPCurve);
  }
  
  ResEdge = BRepLib_MakeEdge(ResCurve,
                             FirstVertex, LastVertex,
                             ResCurve->FirstParameter(), ResCurve->LastParameter());
  BB.SameRange(ResEdge, Standard_False);
  BB.SameParameter(ResEdge, Standard_False);
  for (j = 1; j <= ResPCurves.Length(); j++)
  {
    BB.UpdateEdge(ResEdge, ResPCurves(j), SurfSeq(j), aLoc, MaxTol);
    BB.Range(ResEdge, SurfSeq(j), aLoc, ResPCurves(j)->FirstParameter(), ResPCurves(j)->LastParameter());
  }

  BRepLib::SameParameter(ResEdge, MaxTol, Standard_True);
  
  return ResEdge;
}