/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSGGA_CameraManipulator
#define OSGGA_CameraManipulator 1

#include <osg/Node>
#include <osg/Matrixd>
#include <osg/CoordinateSystemNode>

#include <osgUtil/SceneView>

#include <osgGA/Export>
#include <osgGA/GUIEventHandler>
#include <osgGA/GUIEventAdapter>
#include <osgGA/GUIActionAdapter>

namespace osgGA{

#define NEW_HOME_POSITION

/**

CameraManipulator is an abstract base class defining the interface, and a certain
amount of default functionality, for classes which wish to control OSG cameras
in response to GUI events.

*/
class OSGGA_EXPORT CameraManipulator : public GUIEventHandler
{
        typedef GUIEventHandler inherited;

    public:

        // We are not using META_Object as this is abstract class.
        // Use META_Object(osgGA,YourManipulator); in your descendant non-abstract classes.
        virtual const char* className() const { return "CameraManipulator"; }

        /** callback class to use to allow matrix manipulators to query the application for the local coordinate frame.*/
        class CoordinateFrameCallback : public osg::Referenced
        {
        public:
            virtual osg::CoordinateFrame getCoordinateFrame(const osg::Vec3d& position) const = 0;
        protected:
            virtual ~CoordinateFrameCallback() {}
        };

        /** set the coordinate frame which callback tells the manipulator which way is up, east and north.*/
        virtual void setCoordinateFrameCallback(CoordinateFrameCallback* cb) { _coordinateFrameCallback = cb; }

        /** get the coordinate frame callback which tells the manipulator which way is up, east and north.*/
        CoordinateFrameCallback* getCoordinateFrameCallback() { return _coordinateFrameCallback.get(); }

        /** get the coordinate frame callback which tells the manipulator which way is up, east and north.*/
        const CoordinateFrameCallback* getCoordinateFrameCallback() const { return _coordinateFrameCallback.get(); }

        /** get the coordinate frame.*/
        osg::CoordinateFrame getCoordinateFrame(const osg::Vec3d& position) const
        {
            if (_coordinateFrameCallback.valid()) return  _coordinateFrameCallback->getCoordinateFrame(position);
            return osg::CoordinateFrame();
        }

        osg::Vec3d getSideVector(const osg::CoordinateFrame& cf) const { return osg::Vec3d(cf(0,0),cf(0,1),cf(0,2)); }
        osg::Vec3d getFrontVector(const osg::CoordinateFrame& cf) const { return osg::Vec3d(cf(1,0),cf(1,1),cf(1,2)); }
        osg::Vec3d getUpVector(const osg::CoordinateFrame& cf) const { return osg::Vec3d(cf(2,0),cf(2,1),cf(2,2)); }

        /** set the position of the matrix manipulator using a 4x4 Matrix.*/
        virtual void setByMatrix(const osg::Matrixd& matrix) = 0;

        /** set the position of the matrix manipulator using a 4x4 Matrix.*/
        virtual void setByInverseMatrix(const osg::Matrixd& matrix) = 0;

        /** get the position of the manipulator as 4x4 Matrix.*/
        virtual osg::Matrixd getMatrix() const = 0;

        /** get the position of the manipulator as a inverse matrix of the manipulator, typically used as a model view matrix.*/
        virtual osg::Matrixd getInverseMatrix() const = 0;

        /** update the camera for the current frame, typically called by the viewer classes. 
            Default implementation simply set the camera view matrix. */
        virtual void updateCamera(osg::Camera& camera) { camera.setViewMatrix(getInverseMatrix()); }

        /** Get the FusionDistanceMode. Used by SceneView for setting up stereo convergence.*/
        virtual osgUtil::SceneView::FusionDistanceMode getFusionDistanceMode() const { return osgUtil::SceneView::PROPORTIONAL_TO_SCREEN_DISTANCE; }

        /** Get the FusionDistanceValue. Used by SceneView for setting up stereo convergence.*/
        virtual float getFusionDistanceValue() const { return 1.0f; }

        /** Set the mask to use when set up intersection traversal such as used in manipulators that follow terrain or have collision detection.
          * The intersection traversal mask is useful for controlling what parts of the scene graph should be used for intersection purposes.*/
        void setIntersectTraversalMask(unsigned int mask) { _intersectTraversalMask = mask; }

        /** Get the mask to use when set up intersection traversal such as used in manipulators that follow terrain or have collision detection.*/
        unsigned int getIntersectTraversalMask() const { return _intersectTraversalMask; }

        /**
        Attach a node to the manipulator, automatically detaching any previously attached node.
        setNode(NULL) detaches previous nodes.
        May be ignored by manipulators which do not require a reference model.
        */
        virtual void setNode(osg::Node*) {}

        /** Return const node if attached.*/
        virtual const osg::Node* getNode() const { return NULL; }

        /** Return node if attached.*/
        virtual osg::Node* getNode() { return NULL; }

        /** Manually set the home position, and set the automatic compute of home position. */
        virtual void setHomePosition(const osg::Vec3d& eye, const osg::Vec3d& center, const osg::Vec3d& up, bool autoComputeHomePosition=false)
        {
            setAutoComputeHomePosition(autoComputeHomePosition);
            _homeEye = eye;
            _homeCenter = center;
            _homeUp = up;
        }

        /** Get the manually set home position. */
        virtual void getHomePosition(osg::Vec3d& eye, osg::Vec3d& center, osg::Vec3d& up) const
        {
            eye = _homeEye;
            center = _homeCenter;
            up = _homeUp;
        }

        /** Set whether the automatic compute of the home position is enabled.*/
        virtual void setAutoComputeHomePosition(bool flag) { _autoComputeHomePosition = flag; }

        /** Get whether the automatic compute of the home position is enabled.*/
        bool getAutoComputeHomePosition() const { return _autoComputeHomePosition; }

        /** Compute the home position.*/
        virtual void computeHomePosition(const osg::Camera *camera = NULL, bool useBoundingBox = false);

        /**
        Move the camera to the default position.
        May be ignored by manipulators if home functionality is not appropriate.
        */
        virtual void home(const GUIEventAdapter& ,GUIActionAdapter&) {}

        /**
        Move the camera to the default position.
        This version does not require GUIEventAdapter and GUIActionAdapter so may be
        called from somewhere other than a handle() method in GUIEventHandler.  Application
        must be aware of implications.
        */
        virtual void home(double /*currentTime*/) {}

        /**
        Start/restart the manipulator.
        FIXME: what does this actually mean? Provide examples.
        */
        virtual void init(const GUIEventAdapter& ,GUIActionAdapter&) {}

        /** Handle events, return true if handled, false otherwise. */
        virtual bool handle(const GUIEventAdapter& ea,GUIActionAdapter& us);

    protected:

        CameraManipulator();
        CameraManipulator(const CameraManipulator& mm, const osg::CopyOp& copyOp = osg::CopyOp::SHALLOW_COPY);

        virtual ~CameraManipulator();

        std::string getManipulatorName() const;

        unsigned int            _intersectTraversalMask;

        bool                    _autoComputeHomePosition;

        osg::Vec3d              _homeEye;
        osg::Vec3d              _homeCenter;
        osg::Vec3d              _homeUp;

        osg::ref_ptr<CoordinateFrameCallback> _coordinateFrameCallback;

};

}

#endif
