// File:	GccIter_Lin2dTanObl.cxx
// Created:	Fri Dec 20 15:00:23 1991
// Author:	Remi GILET
//		<reg@topsn3>

//========================================================================
// CREATION D UNE LIGNE TANGENTE A UNE COURBE ET PARALLELE A UNE DROITE. +
//========================================================================

#include <IntAna2d_AnaIntersection.hxx>
#include <IntAna2d_IntPoint.hxx>
#include <GccIter_IsParallel.hxx>
#include <StdFail_NotDone.hxx>
#include <GccEnt_BadQualifier.hxx>
#include <math_FunctionRoot.hxx>
#include <gp_XY.hxx>
#include <gp_Dir2d.hxx>
#include <gp_Vec2d.hxx>
#include <gp_Circ2d.hxx>

GccIter_Lin2dTanObl::
   GccIter_Lin2dTanObl (const TheQualifiedCurve& Qualified1 ,
			const gp_Lin2d&          TheLin     ,
			const Standard_Real      Param1     ,
			const Standard_Real      TolAng     ,
			const Standard_Real      Angle      ) {

   par1sol = 0.;
   pararg1 = 0.;
   WellDone = Standard_False;
   if (!(Qualified1.IsEnclosed() || Qualified1.IsEnclosing() || 
	 Qualified1.IsOutside() || Qualified1.IsUnqualified())) {
     GccEnt_BadQualifier::Raise();
     return;
   }
   Paral2 = Standard_False;
   TheCurve Cu1 = Qualified1.Qualified();
   Standard_Real U1 = TheCurveTool::FirstParameter(Cu1);
   Standard_Real U2 = TheCurveTool::LastParameter(Cu1);
   gp_Dir2d Dir(TheLin.Direction());
   Standard_Real A = Dir.X();
   Standard_Real B = Dir.Y();
   gp_Dir2d TheDirection(Dir);
   if (Abs(Angle) > Abs(TolAng)) {
     if (Abs(Abs(Angle)-PI) <= Abs(TolAng)) {
       Paral2 = Standard_True;
       TheDirection = Dir.Reversed();
     }
     else if (Abs(Angle-PI/2) <= Abs(TolAng)) { TheDirection=gp_Dir2d(-B,A); }
     else if (Abs(Angle+PI/2) <= Abs(TolAng)) { TheDirection=gp_Dir2d(B,-A); }
     else {
       TheDirection=gp_Dir2d(A*Cos(Angle)-B*Sin(Angle),
			     A*Sin(Angle)+B*Cos(Angle));
     }
   }
   else { Paral2 = Standard_True; }
   GccIter_FuncTObl func(Cu1,TheDirection);
   math_FunctionRoot sol(func,Param1,
			 TheCurveTool::EpsX(Cu1,Abs(TolAng)),U1,U2,100);
   if (sol.IsDone()) {
     Standard_Real Usol = sol.Root();
     gp_Pnt2d Origine;
     gp_Vec2d Vect1,Vect2;
     TheCurveTool::D2(Cu1,Usol,Origine,Vect1,Vect2);
     Standard_Real sign1 = Vect1.XY().Dot(TheDirection.XY());
     Standard_Real sign2 = Vect2.XY().Crossed(TheDirection.XY());
     if (Qualified1.IsUnqualified() || 
	 (Qualified1.IsEnclosing() && sign2<=0.) ||
	 (Qualified1.IsOutside() && sign1 <= 0. && sign2 >= 0.) ||
	 (Qualified1.IsEnclosed() && sign1 >= 0. && sign2 >= 0.)) {
       WellDone = Standard_True;
       linsol = gp_Lin2d(Origine,TheDirection);
       pnttg1sol = Origine;
       qualifier1 = Qualified1.Qualifier();
       pararg1 = Usol;
       par1sol = 0.;
       if (!Paral2) {
	 IntAna2d_AnaIntersection Intp(linsol,TheLin);
	 if (Intp.IsDone() && !Intp.IsEmpty()) {
	   if (Intp.NbPoints()==1) {
	     pntint2sol = Intp.Point(1).Value();
	     par2sol = gp_Vec2d(linsol.Direction()).
	       Dot(gp_Vec2d(linsol.Location(),pntint2sol));
	     pararg2 = gp_Vec2d(TheLin.Direction()).
	       Dot(gp_Vec2d(TheLin.Location(),pntint2sol));
	   }
	 }
       }
     }
   }
 }

Standard_Boolean GccIter_Lin2dTanObl::
   IsDone () const { return WellDone; }

gp_Lin2d GccIter_Lin2dTanObl::ThisSolution () const 
{	
  if (!WellDone) StdFail_NotDone::Raise();

  return linsol;
}

void GccIter_Lin2dTanObl:: 
  WhichQualifier (GccEnt_Position& Qualif1) const
{
  if (!WellDone) { StdFail_NotDone::Raise(); }
  else {
    Qualif1 = qualifier1;
  }
}

Standard_Boolean GccIter_Lin2dTanObl::
   IsParallel2 () const { return Paral2; }

void GccIter_Lin2dTanObl::
   Tangency1 (Standard_Real& ParSol    ,
              Standard_Real& ParArg    ,
              gp_Pnt2d& PntSol) const {
   if (!WellDone) { StdFail_NotDone::Raise(); }
   else {
     ParSol = par1sol;
     ParArg = pararg1;
     PntSol = gp_Pnt2d(pnttg1sol);
   }
 }

void GccIter_Lin2dTanObl::
  Intersection2 (Standard_Real&     ParSol ,
		 Standard_Real&     ParArg ,
		 gp_Pnt2d& PntSol ) const {
   if (!WellDone) { StdFail_NotDone::Raise(); }
   else if (Paral2) { GccIter_IsParallel::Raise(); }
   else {
     PntSol = pntint2sol;
     ParSol = par2sol;
     ParArg = pararg2;
   }
 }