/* -*-c++-*- */
/* osgEarth - Geospatial SDK for OpenSceneGraph
 * Copyright 2020 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.
 *
 * This program 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
 * GNU Lesser General Public License for more details.
 *
 * 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/>
 */
#pragma once

#include <osgEarth/AnnotationNode>
#include <osgEarth/GeoData>
#include <osgEarth/Units>
#include <osgEarth/URI>
#include <osgEarth/Terrain>
#include <osgEarth/VirtualProgram>

#include <osgEarth/Feature>

#include <osg/Group>
#include <osg/Geometry>
#include <osg/Image>
#include <osg/MatrixTransform>

namespace osgEarth
{
    /**
     * ImageOverlay drapes a rectangular texture on the terrain.
     */
    class OSGEARTH_EXPORT ImageOverlay : public AnnotationNode
    {
    public:
        META_AnnotationNode(osgEarth, ImageOverlay);
        
        enum ControlPoint
        {
            CONTROLPOINT_CENTER,
            CONTROLPOINT_LOWER_LEFT,
            CONTROLPOINT_LOWER_RIGHT,
            CONTROLPOINT_UPPER_LEFT,
            CONTROLPOINT_UPPER_RIGHT
        };
        
        /**
         * Constructs an image overlay.
         */
        ImageOverlay(MapNode* mapNode, osg::Image* image = NULL);

        /**
         * Construcs an image overlay annotation from a serialized representation
         */
        ImageOverlay(const Config& conf, const osgDB::Options* dbOptions);

        virtual ~ImageOverlay() { }

        void setCorners(const osg::Vec2d& lowerLeft, const osg::Vec2d& lowerRight, 
                        const osg::Vec2d& upperLeft, const osg::Vec2d& upperRight);

        void setLowerLeft(double lon_deg, double lat_deg);
        const osg::Vec2d& getLowerLeft() const { return _lowerLeft; }

        void setLowerRight(double lon_deg, double lat_deg);
        const osg::Vec2d& getLowerRight() const { return _lowerRight;}

        void setUpperLeft(double lon_deg, double lat_deg);
        const osg::Vec2d& getUpperLeft() const { return _upperLeft; }

        void setUpperRight(double lon_deg, double lat_deg);
        const osg::Vec2d& getUpperRight() const { return _upperRight;}

        osg::Vec2d getCenter() const;
        void setCenter(double lon_deg, double lat_deg);

        osg::Vec2d getControlPoint(ControlPoint controlPoint);
        void setControlPoint(ControlPoint controlPoint, double lon_deg, double lat_deg, bool singleVert=false);

        /** When refining the mesh to fit the curtavure of the earth, this is the target resolution of the triangle mesh.
            Default is 5 degrees */
        void setGeometryResolution(const Distance& d) { _geometryResolution = d; }
        const Distance& getGeometryResolution() const { return _geometryResolution; }

        struct ImageOverlayCallback : public osg::Referenced
        {
            virtual void onOverlayChanged() {};
            virtual ~ImageOverlayCallback() { }
        };

        typedef std::list< osg::ref_ptr<ImageOverlayCallback> > CallbackList;

        void addCallback( ImageOverlayCallback* callback );
        void removeCallback( ImageOverlayCallback* callback );


        osgEarth::Bounds getBounds() const;
        void setBounds(const osgEarth::Bounds& bounds);

        void setBoundsAndRotation(const osgEarth::Bounds& bounds, const Angular& rotation);

        osg::Image* getImage() const;
        void setImage( osg::Image* image );

        osg::Texture::FilterMode getMinFilter() const;
        void setMinFilter( osg::Texture::FilterMode filter );

        osg::Texture::FilterMode getMagFilter() const;
        void setMagFilter( osg::Texture::FilterMode filter );

        void setNorth(double value_deg);
        void setSouth(double value_deg);
        void setEast(double value_deg);
        void setWest(double value_deg);

        float getAlpha() const;
        void setAlpha(float alpha);

        void dirty();

        bool getDraped() const;
        void setDraped( bool draped );
        
        /** Serialize the contents of this node */
        Config getConfig() const;


    public: // MapNodeObserver

        virtual void setMapNode( MapNode* mapNode );

    public: // osg::Node

        virtual void traverse(osg::NodeVisitor& nv);

    public:
        
        // callback from Terrain whsen new data arrives
        void onTileUpdate(
            const TileKey&          key, 
            osg::Node*              graph, 
            TerrainCallbackContext& context);
        
    private:
        void fireCallback(ImageOverlay::ControlPoint point, const osg::Vec2d& location);

        void construct();
        void compile();
        void clampLatitudes();

        void updateFilters();

        osg::Node* createNode();

        osg::Vec2d _lowerLeft;
        osg::Vec2d _lowerRight;
        osg::Vec2d _upperRight;
        osg::Vec2d _upperLeft;
        osg::Polytope _boundingPolytope;        
        osg::ref_ptr< osg::Image > _image;
        bool _dirty;
        std::mutex _mutex;

        osg::Group* _root;        
        osg::Texture* _texture;
        Distance _geometryResolution;

        //float _alpha;
        CallbackList _callbacks;

        optional<URI>   _imageURI;
        optional<float> _alpha;
        optional<osg::Texture::FilterMode> _minFilter;
        optional<osg::Texture::FilterMode> _magFilter;
        optional<bool> _draped;

        bool _updateScheduled;

        ImageOverlay() { }
        ImageOverlay(const ImageOverlay&, const osg::CopyOp&) { }
    };

}