/* -*-c++-*- */
/* osgEarth - Dynamic map generation toolkit for OpenSceneGraph
* Copyright 2016 Pelican Mapping
* http://osgearth.org
*
* osgEarth is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>
*/
#ifndef OSGEARTH_UTIL_SIMPLE_PAGER_H
#define OSGEARTH_UTIL_SIMPLE_PAGER_H 1


#include <osgEarthUtil/Common>
#include <osgEarth/Profile>
#include <osgEarth/Progress>
#include <osg/Group>
#include <osg/PagedLOD>

namespace osgEarth { namespace Util {

    using namespace osgEarth;

    class OSGEARTHUTIL_EXPORT SimplePager : public osg::Group
    {
    public:
        SimplePager(const osgEarth::Profile* profile);

        void build();

        /**
         * Get or set whether this pager uses additive lods.
         */
        bool getAdditive() { return _additive; }
        void setAdditive(bool additive) { _additive = additive; }

        unsigned int getMinLevel() const { return _minLevel; }
        void setMinLevel(unsigned int minLevel) { _minLevel = minLevel; }

        unsigned int getMaxLevel() const { return _maxLevel; }
        void setMaxLevel(unsigned int maxLevel) { _maxLevel = maxLevel; }

        float getRangeFactor() const { return _rangeFactor; }
        void setRangeFactor(float value) { _rangeFactor = value; }

        float getPriorityScale() const { return _priorityScale; }
        void setPriorityScale(float value) { _priorityScale = value; }

        float getPriorityOffset() const { return _priorityOffset; }
        void setPriorityOffset(float value) { _priorityOffset = value; }

        void setFileLocationCallback(osgDB::FileLocationCallback* cb) { _fileLocationCallback = cb; }
        osgDB::FileLocationCallback* getFileLocationCallback() const  { return _fileLocationCallback.get(); }

        void setEnableCancelation(bool value);
        bool getEnableCancalation() const;

        /**
         * Gets the profile for the SimplePager.
         */
        const osgEarth::Profile* getProfile() const;

        /**
        * Creates a node for the given TileKey.  Doesn't do anything with paging, just gets the raw data.
        * Subclasses override this method to provide their data for TileKeys
        */
        virtual osg::Node* createNode(const TileKey& key, ProgressCallback* progress);

        /**
         * Callback structure for pager events
         */
        struct Callback : public osg::Referenced
        {
            /**
             * Called after a new tile is created, but before it's merged into the live
             * scene graph. Runs in a pager thread.
             */
            virtual void onCreateNode(const TileKey& key, osg::Node* node) { }
        };

        /** Adds a pager callback. */
        void addCallback(Callback* callback);

        /** Removes a pager callback. */
        void removeCallback(Callback* callback);

    public:
        struct ProgressTracker : public osg::NodeCallback {
            ProgressTracker(osg::NodeCallback*);
            osg::ref_ptr<ProgressCallback> _progress[4];
            void operator()(osg::Node*, osg::NodeVisitor*);
        };

        /**
        * Loads the PagedLOD hierarchy for this key.
        */
        osg::Node* loadKey(const TileKey& key, ProgressTracker* progress);

    protected:

        /**
        * Gets the bounding sphere for a given TileKey.
        */
        osg::BoundingSphere getBounds(const TileKey& key) const;

        /**
        * The root node is a special node.
        */
        osg::Node* buildRootNode();

        /**
        * Creates a PagedLOD for the given TileKEy
        */
        osg::Node* createPagedNode(const TileKey& key, ProgressCallback* progress);

        bool _additive;
        double _rangeFactor;
        unsigned int _minLevel;
        unsigned int _maxLevel;
        osg::ref_ptr< const osgEarth::Profile > _profile;
        osg::ref_ptr< osg::NodeCallback > _progressMaster;
        osg::ref_ptr< osgDB::FileLocationCallback > _fileLocationCallback;
        float _priorityScale;
        float _priorityOffset;
        bool _canCancel;
        
        mutable Threading::Mutex _mutex;
        typedef std::vector< osg::ref_ptr<Callback> > Callbacks;
        Callbacks _callbacks;

        void fire_onCreateNode(const TileKey& key, osg::Node* node);
    };

} } // namespace osgEarth::Util


#endif