// File:	BRepLib_FindSurface.cxx
// Created:	Fri Jul 22 14:03:07 1994
// Author:	Remi LEQUETTE
//		<rle@bravox>

#include <BRepLib_FindSurface.ixx>

#include <Precision.hxx>
#include <math_Matrix.hxx>
#include <math_Vector.hxx>
#include <math_Gauss.hxx>

#include <gp_Lin.hxx>
#include <gp_Circ.hxx>
#include <gp_Elips.hxx>
#include <gp_Hypr.hxx>
#include <gp_Parab.hxx>
#include <gp_Ax2.hxx>
#include <gp_Ax3.hxx>
#include <gp_Vec.hxx>
#include <TColgp_SequenceOfPnt.hxx>
#include <TColStd_SequenceOfReal.hxx>
#include <TColgp_Array1OfPnt.hxx>
#include <TColgp_HArray1OfPnt.hxx>
#include <Geom_Plane.hxx>

#include <TopoDS.hxx>
#include <TopExp_Explorer.hxx>
#include <BRep_Tool.hxx>
#include <BRepAdaptor_Curve.hxx>

#include <GeomLib.hxx>
#include <Geom2d_Curve.hxx>
#include <Geom_BezierCurve.hxx>
#include <Geom_BSplineCurve.hxx>

//=======================================================================
//function : Controle
//purpose  : 
//=======================================================================
static Standard_Real Controle(const TColgp_SequenceOfPnt& thePoints,
			      const Handle(Geom_Plane)& thePlane)
{
  Standard_Real dfMaxDist=0.;
  Standard_Real a,b,c,d, dist;
  Standard_Integer ii;
  thePlane->Coefficients(a,b,c,d);
  for (ii=1; ii<=thePoints.Length(); ii++) {
    const gp_XYZ& xyz = thePoints(ii).XYZ();
    dist = Abs(a*xyz.X() + b*xyz.Y() + c*xyz.Z() + d);
    if (dist > dfMaxDist)
      dfMaxDist = dist;
  }

  return dfMaxDist;
}

//=======================================================================
//function : BRepLib_FindSurface
//purpose  : 
//=======================================================================
BRepLib_FindSurface::BRepLib_FindSurface() 
{
}
//=======================================================================
//function : BRepLib_FindSurface
//purpose  : 
//=======================================================================
BRepLib_FindSurface::BRepLib_FindSurface(const TopoDS_Shape&    S, 
					 const Standard_Real    Tol,
					 const Standard_Boolean OnlyPlane)
{
  Init(S,Tol,OnlyPlane);
}
//=======================================================================
//function : Init
//purpose  : 
//=======================================================================
void BRepLib_FindSurface::Init(const TopoDS_Shape&    S, 
			       const Standard_Real    Tol,
			       const Standard_Boolean OnlyPlane)
{
  myTolerance = Tol;
  myTolReached = 0.;
  isExisted = Standard_False;
  myLocation.Identity();
  mySurface.Nullify();

  // compute the tolerance
  TopExp_Explorer ex;

  for (ex.Init(S,TopAbs_EDGE); ex.More(); ex.Next()) {
    Standard_Real t = BRep_Tool::Tolerance(TopoDS::Edge(ex.Current()));
    if (t > myTolerance) myTolerance = t;
  }

  // search an existing surface
  ex.Init(S,TopAbs_EDGE);
  if (!ex.More()) return;    // no edges ....

  TopoDS_Edge E = TopoDS::Edge(ex.Current());
  Standard_Real f,l,ff,ll;
  Handle(Geom2d_Curve) PC,PPC;
  Handle(Geom_Surface) SS;
  TopLoc_Location L;
  Standard_Integer i = 0,j;

  // iterate on the surfaces of the first edge
  while ( Standard_True) {
    i++;
    BRep_Tool::CurveOnSurface(E,PC,mySurface,myLocation,f,l,i);
    if (mySurface.IsNull()) {
      break;
    }
    // check the other edges
    for (ex.Init(S,TopAbs_EDGE); ex.More(); ex.Next()) {
      if (!E.IsSame(ex.Current())) {
	j = 0;
	while (Standard_True) {
	  j++;
	  BRep_Tool::CurveOnSurface(TopoDS::Edge(ex.Current()),
				    PPC,SS,L,ff,ll,j);
	  if (SS.IsNull()) {
	    break;
	  }
	  if (SS == mySurface) {
	    break;
	  }
	  SS.Nullify();
	}

	if (SS.IsNull()) {
	  mySurface.Nullify();
	  break;
	}
      }
    }

    // if OnlyPlane, eval if mySurface is a plane.
    if ( OnlyPlane && !mySurface.IsNull() ) 
      mySurface = Handle(Geom_Plane)::DownCast(mySurface);

    if (!mySurface.IsNull()) break;
  }

  if (!mySurface.IsNull()) {
    isExisted = Standard_True;
    return;
  }
  //
  // no existing surface, search a plane
  // 07/02/02 akm vvv : (OCC157) changed algorithm
  //                    1. Collect the points along all edges of the shape
  //                       For each point calculate the WEIGHT = sum of
  //                       distances from neighboring points (_only_ same edge)
  //                    2. Minimizing the weighed sum of squared deviations
  //                       compute coefficients of the sought plane.
  
  TColgp_SequenceOfPnt aPoints;
  TColStd_SequenceOfReal aWeight;

  // ======================= Step #1
  for (ex.Init(S,TopAbs_EDGE); ex.More(); ex.Next()) 
  {
    BRepAdaptor_Curve c(TopoDS::Edge(ex.Current()));

    Standard_Real dfUf = c.FirstParameter();
    Standard_Real dfUl = c.LastParameter();
    if (IsEqual(dfUf,dfUl)) {
      // Degenerate
      continue;
    }
    Standard_Integer iNbPoints=0;

    // Add the points with weights to the sequences
    switch (c.GetType()) 
    {
    case GeomAbs_BezierCurve:
      {
	// Put all poles for bezier
	Handle(Geom_BezierCurve) GC = c.Bezier();
	Standard_Integer iNbPol = GC->NbPoles();
	if ( iNbPol < 2)
	  // Degenerate
	  continue;
	else
	{
	  Handle(TColgp_HArray1OfPnt) aPoles = new (TColgp_HArray1OfPnt) (1, iNbPol);
	  GC->Poles(aPoles->ChangeArray1());
	  gp_Pnt aPolePrev = aPoles->Value(1), aPoleNext;
	  Standard_Real dfDistPrev = 0., dfDistNext;
	  for (Standard_Integer iPol=1; iPol<=iNbPol; iPol++)
	  {
	    if (iPol<iNbPol)
	    {
	      aPoleNext = aPoles->Value(iPol+1);
	      dfDistNext = aPolePrev.Distance(aPoleNext);
	    }
	    else
	      dfDistNext = 0.;
	    aPoints.Append (aPolePrev);
	    aWeight.Append (dfDistPrev+dfDistNext);
	    dfDistPrev = dfDistNext;
	    aPolePrev = aPoleNext;
	  }
	}
      }
      break;
    case GeomAbs_BSplineCurve:
      {
	// Put all poles for bspline
	Handle(Geom_BSplineCurve) GC = c.BSpline();
	Standard_Integer iNbPol = GC->NbPoles();
	if ( iNbPol < 2)
	  // Degenerate
	  continue;
	else
	{
	  Handle(TColgp_HArray1OfPnt) aPoles = new (TColgp_HArray1OfPnt) (1, iNbPol);
	  GC->Poles(aPoles->ChangeArray1());
	  gp_Pnt aPolePrev = aPoles->Value(1), aPoleNext;
	  Standard_Real dfDistPrev = 0., dfDistNext;
	  for (Standard_Integer iPol=1; iPol<=iNbPol; iPol++)
	  {
	    if (iPol<iNbPol)
	    {
	      aPoleNext = aPoles->Value(iPol+1);
	      dfDistNext = aPolePrev.Distance(aPoleNext);
	    }
	    else
	      dfDistNext = 0.;
	    aPoints.Append (aPolePrev);
	    aWeight.Append (dfDistPrev+dfDistNext);
	    dfDistPrev = dfDistNext;
	    aPolePrev = aPoleNext;
	  }
	}
      }
      break;

    case GeomAbs_Line:
    case GeomAbs_Circle:
    case GeomAbs_Ellipse:
    case GeomAbs_Hyperbola:
    case GeomAbs_Parabola:
      if (c.GetType() == GeomAbs_Line)
	// Two points on straight segment
	iNbPoints=2;
      else
	// Four points on otheranalitical curves
	iNbPoints=4;
    default:
      { 
	// Put some points on other curves
	if (iNbPoints==0)
	  iNbPoints = 15 + c.NbIntervals(GeomAbs_C3);
	Standard_Real dfDelta = (dfUl-dfUf)/(iNbPoints-1);
	Standard_Integer iPoint;
	Standard_Real dfU;
	gp_Pnt aPointPrev = c.Value(dfUf), aPointNext;
	Standard_Real dfDistPrev = 0., dfDistNext;
	for (iPoint=1, dfU=dfUf+dfDelta; 
	     iPoint<=iNbPoints; 
	     iPoint++, dfU+=dfDelta) 
	{
	  if (iPoint<iNbPoints)
	  {
	    aPointNext = c.Value(dfU);
	    dfDistNext = aPointPrev.Distance(aPointNext);
	  }
	  else
	    dfDistNext = 0.;
	  aPoints.Append (aPointPrev);
	  aWeight.Append (dfDistPrev+dfDistNext);
	  dfDistPrev = dfDistNext;
	  aPointPrev = aPointNext;
	}
      } // default:
    } // switch (c.GetType()) ...
  } // for (ex.Init(S,TopAbs_EDGE); ex.More() && control; ex.Next()) ...
  
  if (aPoints.Length() < 3) {
    return;
  }

  // ======================= Step #2
  myLocation.Identity();
  Standard_Integer iPoint;
  math_Matrix aMat (1,3,1,3, 0.);
  math_Vector aVec (1,3, 0.);
  // Find the barycenter and normalize weights 
  Standard_Real dfMaxWeight=0.;
  gp_XYZ aBaryCenter(0.,0.,0.);
  Standard_Real dfSumWeight=0.;
  for (iPoint=1; iPoint<=aPoints.Length(); iPoint++)  {
    Standard_Real dfW = aWeight(iPoint);
    aBaryCenter += dfW*aPoints(iPoint).XYZ();
    dfSumWeight += dfW;
    if (dfW > dfMaxWeight) {
      dfMaxWeight = dfW;
    }
  }
  aBaryCenter /= dfSumWeight;

  // Fill the matrix and the right vector
  for (iPoint=1; iPoint<=aPoints.Length(); iPoint++)  {
    gp_XYZ p=aPoints(iPoint).XYZ()-aBaryCenter;
    Standard_Real w=aWeight(iPoint)/dfMaxWeight;
    aMat(1,1)+=w*p.X()*p.X(); 
        aMat(1,2)+=w*p.X()*p.Y(); 
            aMat(1,3)+=w*p.X()*p.Z();
    aMat(2,1)+=w*p.Y()*p.X();  
        aMat(2,2)+=w*p.Y()*p.Y();  
            aMat(2,3)+=w*p.Y()*p.Z();
    aMat(3,1)+=w*p.Z()*p.X();  
        aMat(3,2)+=w*p.Z()*p.Y(); 
            aMat(3,3)+=w*p.Z()*p.Z();
    aVec(1) -= w*p.X();
    aVec(2) -= w*p.Y();
    aVec(3) -= w*p.Z();
  }

  // Solve the system of equations to get plane coefficients
  math_Gauss aSolver(aMat);
  Standard_Boolean isSolved = aSolver.IsDone();
  //
  //  let us be more tolerant (occ415)
  Standard_Real dfDist = RealLast();
  Handle(Geom_Plane) aPlane;
  //
  if (isSolved)  {
    aSolver.Solve(aVec);
    if (aVec.Norm2()<gp::Resolution()) {
      isSolved = Standard_False;
    }
  }
  //
  if (isSolved)  {
    aPlane = new Geom_Plane(aBaryCenter,gp_Dir(aVec(1),aVec(2),aVec(3)));
    dfDist = Controle (aPoints, aPlane);
  }
  //
  if (!isSolved || myTolerance < dfDist)  {
    gp_Pnt aFirstPnt=aPoints(1);
    for (iPoint=2; iPoint<=aPoints.Length(); iPoint++)  {
      gp_Vec aDir(aFirstPnt,aPoints(iPoint));
      Standard_Real dfSide=aDir.Magnitude();
      if (dfSide<myTolerance) {
	continue; // degeneration
      }
      for (Standard_Integer iP1=iPoint+1; iP1<=aPoints.Length(); iP1++) {
	gp_Vec aCross = gp_Vec(aFirstPnt,aPoints(iP1)) ^ aDir ;
	if (aCross.Magnitude() > dfSide*myTolerance) {
	  Handle(Geom_Plane) aPlane2 = new Geom_Plane(aFirstPnt, aCross);
	  Standard_Real dfDist2 = Controle (aPoints, aPlane2);
	  if (dfDist2 < myTolerance)  {
	    myTolReached = dfDist2;
	    mySurface = aPlane2;
	    return;
	  }
	  if (dfDist2 < dfDist)  {
	    dfDist = dfDist2;
	    aPlane = aPlane2;
	  }
	}
      }
    }
  }
  //
  //XXf
  //static Standard_Real weakness = 5.0;
  Standard_Real weakness = 5.0;
  //XXf
  if(dfDist <= myTolerance || dfDist < myTolerance*weakness && Tol<0) { 
    //XXf 
    //myTolReached = dfDist;
    //XXt
    mySurface = aPlane;
  }
  //XXf
  myTolReached = dfDist;
  //XXt
}
//=======================================================================
//function : Found
//purpose  : 
//=======================================================================
Standard_Boolean BRepLib_FindSurface::Found() const 
{
  return !mySurface.IsNull();
}
//=======================================================================
//function : Surface
//purpose  : 
//=======================================================================
Handle(Geom_Surface) BRepLib_FindSurface::Surface() const 
{
  return mySurface;
}
//=======================================================================
//function : Tolerance
//purpose  : 
//=======================================================================
Standard_Real BRepLib_FindSurface::Tolerance() const 
{
  return myTolerance;
}
//=======================================================================
//function : ToleranceReached
//purpose  : 
//=======================================================================
Standard_Real BRepLib_FindSurface::ToleranceReached() const 
{
  return myTolReached;
}
//=======================================================================
//function : Existed
//purpose  : 
//=======================================================================
Standard_Boolean BRepLib_FindSurface::Existed() const 
{
  return isExisted;
}
//=======================================================================
//function : Location
//purpose  : 
//=======================================================================
TopLoc_Location BRepLib_FindSurface::Location() const
{
  return myLocation;
}