/* -*-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 OSG_SEQUENCE
#define OSG_SEQUENCE 1

#include <osg/Group>

namespace osg 
{
  
/** Sequence is a Group node which allows automatic, time based
switching between children.
*/
class OSG_EXPORT Sequence : public Group
{
    public :

        Sequence();

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        Sequence(const Sequence&, const CopyOp& copyop=CopyOp::SHALLOW_COPY);

        META_Node(osg, Sequence);

        virtual void traverse(NodeVisitor& nv);

        // the relationship between the _frameTime vector and the _children
        // vector is a bit of a mess.  This is how it was in previous versions,
        // and there's no way out of it if upward compatibility needs to be
        // maintained.  New code should set defaultTime and use addChild, and
        // not mess with the setTime method

        virtual bool addChild( Node *child);

        virtual bool addChild( Node *child, double t);

        virtual bool insertChild( unsigned int index, Node *child);

        virtual bool insertChild( unsigned int index, Node *child, double t);

        virtual bool removeChild( Node *child );

        virtual bool removeChildren(unsigned int pos,unsigned int numChildrenToRemove);


        /** value is which child node is to be displayed */
        void setValue(int value) { _value = value ; }
        int getValue() const { return _value; }

        /** Set time in seconds for child. */
        void setTime(unsigned int frame, double t);

        /** Get time for child. */
        double getTime(unsigned int frame) const;

        /** Set default time in seconds for new child. 
            if t<0, t=0 */
        void setDefaultTime(double t) {_defaultTime = (t<0.?0.:t);}

        /** Get default time in seconds for new child. */
        double getDefaultTime(void) const {return _defaultTime;};

        /** Set time of last frame of last loop, in seconds.  
            if t<= 0, then ignored */
        void setLastFrameTime(double t) {_lastFrameTime = (t<0.?0.:t);}

        /** Get last frame time in seconds */
        double getLastFrameTime(void) const {return _lastFrameTime;};

        /** Get number of frames */
        inline unsigned int getNumFrames() const { return _frameTime.size(); }

        /** Interval modes. 'Loop' repeats frames 1-N; 'swing' repeats 1->N, (N-1)->1. */
        enum LoopMode
        {
            LOOP,
            SWING
        };

        /** Set sequence mode & interval (range of children to be displayed). */
        void setInterval(LoopMode mode, int begin, int end);

        /** Get sequence mode & interval. */
        inline void getInterval(LoopMode& mode, int& begin, int& end) const
        {
            mode = _loopMode;
            begin = _begin;
            end = _end;
        }

        /** Set duration: speed-up & number of repeats */
        void setDuration(float speed, int nreps = -1);

        /** Get duration & number of repeats. */
        inline void getDuration(float& speed, int& nreps) const
        {
            speed = _speed;
            nreps = _nreps;
        }

        /** Sequence modes. */
        enum SequenceMode
        {
            START,
            STOP,
            PAUSE,
            RESUME
        };

        /** Set sequence mode. Start/stop & pause/resume. */
        void setMode(SequenceMode mode);

        /** Get sequence mode. */
        inline SequenceMode getMode() const { return _mode; }

        /** If false (default), frames will not be sync'd to frameTime.  If
            true, frames will be sync'd to frameTime. */
        void setSync(bool sync) { _sync = sync ; } ;

        /** Get sync value */
        inline void getSync(bool& sync) const { sync = _sync ; } ;

        /** If true, show no child nodes after stopping */
        void setClearOnStop(bool clearOnStop) { _clearOnStop = clearOnStop ; } ;

        /** If true, show no child nodes after stopping */
        inline void getClearOnStop(bool& clearOnStop) const { clearOnStop = _clearOnStop ; } ;

    protected :

        virtual ~Sequence() {}

        // get next _value in sequence
        int _getNextValue(void) ;

        // update local variables
        void _update(void) ;

        // init to -1 to mean "restart"
        int _value;

        // current time, set by traverse
        double _now ;

        // time this frame started.  init to -1.0f- means get current time
        double _start;

        // a vector of frame times, one per value
        std::vector<double> _frameTime;

        // the total time for one sequence, from BEGIN to END
        double _totalTime ;

        // true if _totalTime needs to be recalculated because setTime or
        // setInterval was invoked, or a new child was added
        bool _resetTotalTime ;

        // store "loop mde", either LOOP or SWING
        // init to LOOP- set by setInterval
        LoopMode _loopMode;

        // first and last "values" to sequence through
        // begin inits to 0
        // end inits to -1- means to init to number of values
        int _begin, _end;

        // multiplier of real-time clock- set to N to go N times faster
        // init to 0- going nowhere
        float _speed;

        // _nreps: how many times to repeat- default param is -1, repeat forever
        // init to 0, no repetitions
        // _nrepsRemain: set to nreps and counts down every traversal, 
        // stopping when it gets to zero.  init to 0
        int _nreps, _nrepsRemain;

        // frame step (are we stepping forward or backward?)
        int _step;

        // default frame time for newly created frames or children- default is 1.
        // set by setDefaultTime
        double _defaultTime ;

        // special time to display last frame of last loop
        // <= zero means to not do anything special
        double _lastFrameTime ;

        // save the actual time of the last frame, and what value was stored
        double _saveRealLastFrameTime ;
        unsigned int _saveRealLastFrameValue ;

        // the current mode
        SequenceMode _mode;

        // the current sync value
        bool _sync ;

        // the current clearOnStop value
        bool _clearOnStop ;

};
  
}

#endif
