//C++ header - Open Scene Graph - Copyright (C) 1998-2002 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSG_ANIMATIONPATH
#define OSG_ANIMATIONPATH 1

#include <osg/Matrix>
#include <osg/Quat>

#include <map>

namespace osg {

/** AnimationPath for specify the time varying transformation pathway to use when update camera and model objects.
  * Subclassed from Transform::ComputeTransformCallback allows AnimationPath to
  * be attached directly to Transform nodes to move subgraphs around the scene.
*/
class SG_EXPORT AnimationPath : public osg::Referenced
{
    public:
    
        AnimationPath():_loopMode(LOOP) {}

        struct ControlPoint
        {
            ControlPoint():
                _scale(1.0f,1.0f,1.0f) {}

            ControlPoint(const osg::Vec3& position):
                _position(position),
                _rotation(),
                _scale(1.0f,1.0f,1.0f) {}

            ControlPoint(const osg::Vec3& position, const osg::Quat& rotation):
                _position(position),
                _rotation(rotation),
                _scale(1.0f,1.0f,1.0f) {}

            ControlPoint(const osg::Vec3& position, const osg::Quat& rotation, const osg::Vec3& scale):
                _position(position),
                _rotation(rotation),
                _scale(scale) {}
        
            osg::Vec3 _position;
            osg::Quat _rotation;
            osg::Vec3 _scale;
            
            inline void interpolate(float ratio,const ControlPoint& first, const ControlPoint& second)
            {
                float one_minus_ratio = 1.0f-ratio;
                _position = first._position*one_minus_ratio + second._position*ratio;
                _rotation.slerp(ratio,first._rotation,second._rotation);
                _scale = first._scale*one_minus_ratio + second._scale*ratio;
            }
            
            inline void getMatrix(Matrix& matrix) const
            {
                matrix.makeScale(_scale);
                matrix.postMult(_rotation.getMatrix());
                matrix.postMult(osg::Matrix::translate(_position));
            }

            inline void getInverse(Matrix& matrix) const
            {
                matrix.makeScale(1.0f/_scale.x(),1.0f/_scale.y(),1.0f/_scale.y());
                matrix.postMult(_rotation.inverse().getMatrix());
                matrix.postMult(osg::Matrix::translate(-_position));
            }
        };
        

        /** get the transformation matrix for a point in time.*/        
        bool getMatrix(double time,Matrix& matrix) const
        {
            ControlPoint cp;
            if (!getInterpolatedControlPoint(time,cp)) return false;
            cp.getMatrix(matrix);
            return true;
        }

        /** get the inverse transformation matrix for a point in time.*/        
        bool getInverse(double time,Matrix& matrix) const
        {
            ControlPoint cp;
            if (!getInterpolatedControlPoint(time,cp)) return false;
            cp.getInverse(matrix);
            return true;
        }
        
        /** get the local ControlPoint frame for a point in time.*/
        virtual bool getInterpolatedControlPoint(double time,ControlPoint& controlPoint) const;
        
        void insert(double time,const ControlPoint& controlPoint);
        
        double getFirstTime() const { if (!_timeControlPointMap.empty()) return _timeControlPointMap.begin()->first; else return 0.0;}
        double getLastTime() const { if (!_timeControlPointMap.empty()) return _timeControlPointMap.rbegin()->first; else return 0.0;}
        double getPeriod() const { return getLastTime()-getFirstTime();}
        
        enum LoopMode
        {
            SWING,
            LOOP,
            NO_LOOPING
        };
        
        void setLoopMode(LoopMode lm) { _loopMode = lm; }
        
        LoopMode getLoopMode() const { return _loopMode; }

    protected:
    
        virtual ~AnimationPath() {}

        typedef std::map<double,ControlPoint> TimeControlPointMap;
        
        TimeControlPointMap _timeControlPointMap;
        LoopMode            _loopMode;

};

}

#endif