/* -*-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_PagedLOD
#define OSG_PagedLOD 1

#include <osg/LOD>

namespace osg {

/** PagedLOD.
*/
class OSG_EXPORT PagedLOD : public LOD
{
    public :
    
        PagedLOD();

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

        META_Node(osg, PagedLOD);
        
        

        virtual void traverse(NodeVisitor& nv);
        
        virtual bool addChild(Node *child);

        virtual bool addChild(Node *child, float min, float max);

        virtual bool addChild(Node *child, float min, float max,const std::string& filename, float priorityOffset=0.0f, float priorityScale=1.0f);

        virtual bool removeChildren(unsigned int pos,unsigned int numChildrenToRemove=1);
        


        /** Set the database path to prepend to children's filenames.*/
        void setDatabasePath(const std::string& path);

        /** Get the database path used to prepend to children's filenames.*/
        inline const std::string& getDatabasePath() const { return _databasePath; }

        
        struct OSG_EXPORT PerRangeData
        {
            PerRangeData();
            PerRangeData(const PerRangeData& prd);
            PerRangeData& operator = (const PerRangeData& prd);

            std::string                     _filename;
            float                           _priorityOffset;
            float                           _priorityScale;
            double                          _timeStamp;
            osg::ref_ptr<osg::Referenced>   _databaseRequest;
        };

        typedef std::vector<PerRangeData> PerRangeDataList;
        
        void setFileName(unsigned int childNo, const std::string& filename) { expandPerRangeDataTo(childNo); _perRangeDataList[childNo]._filename=filename; }
        const std::string& getFileName(unsigned int childNo) const { return _perRangeDataList[childNo]._filename; }
        unsigned int getNumFileNames() const { return _perRangeDataList.size(); }


        void setPriorityOffset(unsigned int childNo, float priorityOffset) { expandPerRangeDataTo(childNo); _perRangeDataList[childNo]._priorityOffset=priorityOffset; }
        float getPriorityOffset(unsigned int childNo) const { return _perRangeDataList[childNo]._priorityOffset; }
        unsigned int getNumPriorityOffsets() const { return _perRangeDataList.size(); }

        void setPriorityScale(unsigned int childNo, float priorityScale) { expandPerRangeDataTo(childNo); _perRangeDataList[childNo]._priorityScale=priorityScale; }
        float getPriorityScale(unsigned int childNo) const { return _perRangeDataList[childNo]._priorityScale; }
        unsigned int getNumPriorityScales() const { return _perRangeDataList.size(); }


        void setTimeStamp(unsigned int childNo, double timeStamp) { expandPerRangeDataTo(childNo); _perRangeDataList[childNo]._timeStamp=timeStamp; }
        double getTimeStamp(unsigned int childNo) const { return _perRangeDataList[childNo]._timeStamp; }
        unsigned int getNumTimeStamps() const { return _perRangeDataList.size(); }


        /** Return the DatabaseRequest object used by the DatabasePager to keep track of file load requests 
          * being carried on behalf of the DatabasePager.
          * Note, in normal OSG usage you should not set this value yourself, as this will be managed by 
          * the osgDB::DatabasePager.*/
        osg::ref_ptr<osg::Referenced>& getDatabaseRequest(unsigned int childNo) { return _perRangeDataList[childNo]._databaseRequest; }
        
        /** Return the const DatabaseRequest object.*/ 
        const osg::ref_ptr<osg::Referenced>& getDatabaseRequest(unsigned int childNo) const { return _perRangeDataList[childNo]._databaseRequest; }


        /** Set the frame number of the last time that this PageLOD node was traversed.
          * Note, this frame number is automatically set by the traverse() method for all traversals (update, cull etc.). 
          */
        inline void setFrameNumberOfLastTraversal(int frameNumber) { _frameNumberOfLastTraversal=frameNumber; }

        /** Get the frame number of the last time that this PageLOD node was traversed.*/
        inline int getFrameNumberOfLastTraversal() const { return _frameNumberOfLastTraversal; }


        /** Set the number of children that the PagedLOD must keep around, even if they are older than their expiry time.*/
        inline void setNumChildrenThatCannotBeExpired(unsigned int num) { _numChildrenThatCannotBeExpired = num; }

        /** Get the number of children that the PagedLOD must keep around, even if they are older than their expiry time.*/
        unsigned int getNumChildrenThatCannotBeExpired() const { return _numChildrenThatCannotBeExpired; }

        /** Remove the children from the PagedLOD which haven't been visited since specified expiry time.
          * The removed children are added to the removeChildren list passed into the method,
          * this allows the children to be deleted later at the caller's discretion.
          * Return true if children are removed, false otherwise. */
        virtual bool removeExpiredChildren(double expiryTime,NodeList& removedChildren);
        
        

    protected :
    
        virtual ~PagedLOD();
        
        void expandPerRangeDataTo(unsigned int pos);

        std::string         _databasePath;

        int                 _frameNumberOfLastTraversal;
        unsigned int        _numChildrenThatCannotBeExpired;
        PerRangeDataList    _perRangeDataList;
};

}

#endif