// @(#)root/mathcore:$Name:  $:$Id: AxisAngle.h,v 1.3 2005/09/19 16:43:07 brun Exp $
// Authors: W. Brown, M. Fischler, L. Moneta    2005  

/**********************************************************************
  *                                                                    *
  * Copyright (c) 2005 , LCG ROOT MathLib Team                         *
  *                                                                    *
  *                                                                    *
  **********************************************************************/

// Header file for class AxisAngle
//
// Created by: Lorenzo Moneta  at Wed May 11 10:37:10 2005
//
// Last update: Wed May 11 10:37:10 2005
//
#ifndef ROOT_Math_GenVector_AxisAngle 
#define ROOT_Math_GenVector_AxisAngle  1

#include "Math/GenVector/Rotation3D.h"
#include "Math/GenVector/DisplacementVector3D.h"
#include "Math/GenVector/PositionVector3D.h"
#include "Math/GenVector/LorentzVector.h"
#include "Math/GenVector/3DConversions.h"
#include <algorithm>
#include <cassert>


namespace ROOT {
namespace Math {


  /**
     AxisAngle class describing a rotation as a direction axis and an
     angle of rotation around that axis.

     @ingroup GenVector

  */
class AxisAngle {

public:

  typedef double Scalar;

  /**
     definition of vector axis
   */
  typedef DisplacementVector3D<Cartesian3D<Scalar> > AxisVector;


  /**
     Default constructor (axis is z and angle is zero)
  */
  AxisAngle() : fAxis(0,0,1), fAngle(0) { }

  /**
     Construct from a non-zero vector (x,y,z) and an angle.
     Precondition:  the Vector needs to implement x(), y(), z(), and unit()
  */
  template<class AnyVector>
  AxisAngle(const AnyVector & v, Scalar angle) :
                                        fAxis(v.unit()), fAngle(angle) { }

  /**
     Construct given a pair of pointers or iterators defining the
     beginning and end of an array of four Scalars, to be treated as
     the x, y, and z components of a unit axis vector, and the angle
     of rotation.
     Precondition:  The first three components are assumed to represent
     a unit vector.  The angle is assumed to be in the rand (-pi,pi].
     NO checking or re-adjusting is performed.
   */
  template<class IT>
  AxisAngle(IT begin, IT end) { SetComponents(begin,end); }

  // The compiler-generated copy ctor, copy assignment, and dtor are OK.

  /**
     Re-adjust components to eliminate small deviations from the axis
     being a unit vector and angles out of the canonical range (-pi,pi]
   */
  void Rectify();

  // ======== Construction From other Rotation Forms ==================

  /**
     Construct from a rotation matrix
  */
  explicit AxisAngle(const Rotation3D & r) {gv_detail::convert(r,*this);}

  /**
     Construct from EulerAngles
  */
  explicit AxisAngle(const EulerAngles & e) {gv_detail::convert(e,*this);}

  /**
     Construct from a rotation represented by a Quaternion
  */
  explicit AxisAngle(const Quaternion & q) {gv_detail::convert(q,*this);}

  /**
     Construct from an axial rotation
  */
  explicit AxisAngle( RotationZ const & r ) { gv_detail::convert(r, *this); }
  explicit AxisAngle( RotationY const & r ) { gv_detail::convert(r, *this); }
  explicit AxisAngle( RotationX const & r ) { gv_detail::convert(r, *this); }

  /**
     Assign from a Rotation3D
  */
  AxisAngle &
  operator=( Rotation3D const  & r ) { return operator=(AxisAngle(r)); }

  /**
     Assign from EulerAngles
  */
  AxisAngle &
  operator=( EulerAngles const & e ) { return operator=(AxisAngle(e)); }

  /**
     Assign from a Quaternion
  */
  AxisAngle &
  operator=( Quaternion const  & q ) {return operator=(AxisAngle(q)); }

  /**
     Assign from an axial rotation
  */
  AxisAngle &
  operator=( RotationZ const & r ) { return operator=(AxisAngle(r)); }
  AxisAngle &
  operator=( RotationY const & r ) { return operator=(AxisAngle(r)); }
  AxisAngle &
  operator=( RotationX const & r ) { return operator=(AxisAngle(r)); }

  // ======== Components ==============

  /**
     Set the axis and then the angle given a pair of pointers or iterators
     defining the beginning and end of an array of four Scalars.
     Precondition:  The axis is assumed to represent a unit vector.
     NO checking or re-adjusting is performed.
   */
  template<class IT>
  void SetComponents(IT begin, IT end) {
    assert (end==begin+4);
    fAxis.SetCoordinates(begin, begin+3);
    fAngle = *(begin+3);
  }

  /**
     Get the axis and then the angle into data specified by an iterator begin
     and another to the end of the desired data (4 past start).
   */
  template<class IT>
  void GetComponents(IT begin, IT end) const {
    assert (end==begin+4);
    fAxis.GetCoordinates(begin, begin+3);
    *(begin+3) = fAngle;
  }

  /**
     Set components from a non-zero vector (x,y,z) and an angle.
     Precondition:  the Vector needs to implement x(), y(), z(), and unit()
  */
  template<class AnyVector>
  void SetComponents(const AnyVector & v, Scalar angle) {
    fAxis=v.unit();
    fAngle=angle;
  }

  /**
     Set components into a non-zero vector (x,y,z) and an angle.
     The vector is intended to be a cartesian dispalcement vector
     but any vector class assignable from one will work.
  */
  template<class AnyVector>
  void GetComponents(AnyVector & axis, Scalar & angle) const {
    axis  = fAxis;
    angle = fAngle;
  }

  /**
     accesss to rotation axis
   */
  AxisVector Axis() const { return fAxis; }

  /**
     access to rotation angle
   */
  Scalar Angle() const { return fAngle; }

  // =========== operations ==============

  /**
     Rotation operation on a cartesian vector
   */
  DisplacementVector3D< ROOT::Math::Cartesian3D<double> >
    operator() (const DisplacementVector3D< ROOT::Math::Cartesian3D<double> > & v) const;

  /**
     Rotation operation on a displacement vector in any coordinate system
   */
  template <class CoordSystem>
  DisplacementVector3D<CoordSystem>
  operator() (const DisplacementVector3D<CoordSystem> & v) const {
    DisplacementVector3D< Cartesian3D<double> > xyz(v);
    DisplacementVector3D< Cartesian3D<double> > Rxyz = operator()(xyz);
    return DisplacementVector3D<CoordSystem> ( Rxyz );
  }

  /**
     Rotation operation on a position vector in any coordinate system
   */
  template <class CoordSystem>
  PositionVector3D<CoordSystem>
  operator() (const PositionVector3D<CoordSystem> & v) const {
    DisplacementVector3D< Cartesian3D<double> > xyz(v);
    DisplacementVector3D< Cartesian3D<double> > Rxyz = operator()(xyz);
    return PositionVector3D<CoordSystem> ( Rxyz );
  }

  /**
     Rotation operation on a Lorentz vector in any 4D coordinate system
   */
  template <class CoordSystem>
  LorentzVector<CoordSystem>
  operator() (const LorentzVector<CoordSystem> & v) const {
    DisplacementVector3D< Cartesian3D<double> > xyz(v.Vec());
    xyz = operator()(xyz);
    LorentzVector< PxPyPzE4D<double> > xyzt (xyz.X(), xyz.Y(), xyz.Z(), v.E());
    return LorentzVector<CoordSystem> ( xyzt );
  }


  /**
     Rotation operation on an arbitrary vector v.
     Preconditions:  v must implement methods x(), y(), and z()
     and the arbitrary vector type must have a constructor taking (x,y,z)
   */
  template <class ForeignVector>
  ForeignVector
  operator() (const  ForeignVector & v) const {
    DisplacementVector3D< Cartesian3D<double> > xyz(v);
    DisplacementVector3D< Cartesian3D<double> > Rxyz = operator()(xyz);
    return ForeignVector ( Rxyz.X(), Rxyz.Y(), Rxyz.Z() );
  }

  /**
     Overload operator * for rotation on a vector
   */
  template <class AVector>
  inline
  AVector operator* (const AVector & v) const
  {
    return operator()(v);
  }

  /**
      Invert an AxisAngle rotation in place
   */
  void Invert() { fAngle = -fAngle; }

  /**
      Return inverse of an AxisAngle rotation
   */
  AxisAngle Inverse() const { AxisAngle result(*this); result.Invert(); return result; }

  // ========= Multi-Rotation Operations ===============

  /**
     Multiply (combine) two rotations
   */
  AxisAngle operator * (const Rotation3D  & r) const;
  AxisAngle operator * (const AxisAngle   & a) const;
  AxisAngle operator * (const EulerAngles & e) const;
  AxisAngle operator * (const Quaternion  & q) const;
  AxisAngle operator * (const RotationX  & rx) const;
  AxisAngle operator * (const RotationY  & ry) const;
  AxisAngle operator * (const RotationZ  & rz) const;

  /**
     Post-Multiply (on right) by another rotation :  T = T*R
   */
  template <class R>
  AxisAngle & operator *= (const R & r) { return *this = (*this)*r; }


  /**
     Distance between two rotations
   */
  template <class R>
  Scalar Distance ( const R & r ) {return gv_detail::dist(*this,r);}

  /**
     Equality/inequality operators
   */
  bool operator == (const AxisAngle & rhs) {
    if( fAxis  != rhs.fAxis  )  return false;
    if( fAngle != rhs.fAngle )  return false;
    return true;
  }
  bool operator != (const AxisAngle & rhs) {
    return ! operator==(rhs);
  }

private:

  AxisVector  fAxis;
  Scalar      fAngle;

  void RectifyAngle();

  static double Pi() { return 3.14159265358979323; }

};  // AxisAngle

// ============ Class AxisAngle ends here ============

/**
   Distance between two rotations
 */
template <class R>
inline
typename AxisAngle::Scalar
Distance ( const AxisAngle& r1, const R & r2) {return gv_detail::dist(r1,r2);}

/**
   Multiplication of an axial rotation by an AxisAngle
 */
AxisAngle operator* (RotationX const & r1, AxisAngle const & r2);
AxisAngle operator* (RotationY const & r1, AxisAngle const & r2);
AxisAngle operator* (RotationZ const & r1, AxisAngle const & r2);

/**
   Stream Output and Input
 */
  // TODO - I/O should be put in the manipulator form 

std::ostream & operator<< (std::ostream & os, const AxisAngle & a);

} // namespace Math
} // namespace ROOT


#endif /* ROOT_Math_GenVector_AxisAngle  */