/* -*-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/>
 */

#ifndef OSGEARTH_COMPOSITE_H
#define OSGEARTH_COMPOSITE_H

#include <osgEarth/Common>
#include <osgEarth/ImageLayer>
#include <osgEarth/ElevationLayer>
#include <osgEarth/LandCoverLayer>

namespace osgEarth
{
    /**
     * Composite Image Layer combines multiple image layers into one.
     */
    class OSGEARTH_EXPORT CompositeImageLayer : public ImageLayer
    {
    public: // serialization
        class OSGEARTH_EXPORT Options : public ImageLayer::Options {
        public:
            enum Function { FUNCTION_BLEND, FUNCTION_LESS, FUNCTION_GREATER };
            META_LayerOptions(osgEarth, Options, ImageLayer::Options);
            OE_OPTION_VECTOR(ConfigOptions, layers);
            OE_OPTION(int, function);
            virtual Config getConfig() const;
        private:
            void fromConfig(const Config& conf);
        };

    public:
        META_Layer(osgEarth, CompositeImageLayer, Options, ImageLayer, CompositeImage);

    public:

        //! Adds a layer to the composite.
        void addLayer(ImageLayer* layer);

        //! Layers in the composite
        const ImageLayerVector& getLayers() const;

    public: // Layer
        
        //! Opens all composited layers and only returns OK if all layers
        //! open succesfully
        virtual Status openImplementation();

        //! Close all composited layers
        virtual Status closeImplementation();

        //! Creates a raster image for the given tile key
        virtual GeoImage createImageImplementation(const TileKey& key, ProgressCallback* progress) const;

        //! Scene graph containing any nodes from the composited image layers
        virtual osg::Node* getNode() const;

        //! Called when a layer is added to the map
        virtual void addedToMap(const Map* map);
        virtual void removedFromMap(const Map* map);

    protected: // Layer

        //! Called by constructors
        virtual void init();

    protected:

        //! Destructor
        virtual ~CompositeImageLayer() { }

    private:

        ImageLayerVector _layers;
        osg::ref_ptr<osg::Group> _layerNodes;
    };


    /**
     * Elevation layer that composites one or more other ElevationLayers.
     */
    class OSGEARTH_EXPORT CompositeElevationLayer : public ElevationLayer
    {
    public: // serialization
        class OSGEARTH_EXPORT Options : public ElevationLayer::Options {
        public:
            META_LayerOptions(osgEarth, Options, ElevationLayer::Options);
            OE_OPTION_VECTOR(ConfigOptions, layers);
            virtual Config getConfig() const;
        private:
            void fromConfig(const Config& conf);
        };

    public:
        META_Layer(osgEarth, CompositeElevationLayer, Options, ElevationLayer, CompositeElevation);

    public:

        //! Adds a layer to the composite.
        void addLayer(ElevationLayer* layer);

        //! Layers in the composite
        const ElevationLayerVector& getLayers() const;

    public: // Layer
        
        //! Opens all composited layers and only returns OK if all layers
        //! open succesfully
        Status openImplementation() override;

        //! Close all composited layers
        Status closeImplementation() override;

        //! Creates a heightfield for the given tile key
        GeoHeightField createHeightFieldImplementation(const TileKey& key, ProgressCallback* progress) const override;

        //! Scene graph containing any nodes from the composited layers
        osg::Node* getNode() const override;

    protected: // Layer

        //! Called by constructors
        void init() override;

        //! Called when a layer is added to the map
        void addedToMap(const Map* map) override;
        void removedFromMap(const Map* map) override;

    protected:

        //! Destructor
        virtual ~CompositeElevationLayer() { }

    private:

        ElevationLayerVector _layers;
        osg::ref_ptr<osg::Group> _layerNodes;
    };



    /**
    * Composite Layer combines multiple land cover layers into one.
    */
    class OSGEARTH_EXPORT CompositeLandCoverLayer : public LandCoverLayer
    {
    public: // serialization
        class OSGEARTH_EXPORT Options : public LandCoverLayer::Options {
        public:
            META_LayerOptions(osgEarth, Options, LandCoverLayer::Options);
            OE_OPTION_VECTOR(ConfigOptions, layers);
            virtual Config getConfig() const;
        private:
            void fromConfig(const Config& conf);
        };

    public:
        META_Layer(osgEarth, CompositeLandCoverLayer, Options, LandCoverLayer, CompositeLandCover);

    public:

        //! Adds a layer to the composite.
        void addLayer(LandCoverLayer* layer);

        //! Layers in the composite
        const LandCoverLayerVector& getLayers() const;

    public: // Layer

        //! Opens all composited layers and only returns OK if all layers
        //! open succesfully
        virtual Status openImplementation();

        //! Close all composited layers
        virtual Status closeImplementation();

        //! Scene graph containing any nodes from the composited image layers
        virtual osg::Node* getNode() const;

        //! Called when a layer is added to the map
        virtual void addedToMap(const Map* map);
        virtual void removedFromMap(const Map* map);

    protected: // Layer

        //! Called by constructors
        virtual void init();

        //! Creates a raster image for the given tile key
        virtual GeoImage createImageImplementation(const TileKey& key, ProgressCallback* progress) const override;

    protected:

        //! Destructor
        virtual ~CompositeLandCoverLayer() { }

    private:

        LandCoverLayerVector _layers;
        osg::ref_ptr<osg::Group> _layerNodes;
    };



} // namespace osgEarth

OSGEARTH_SPECIALIZE_CONFIG(osgEarth::CompositeImageLayer::Options);
OSGEARTH_SPECIALIZE_CONFIG(osgEarth::CompositeElevationLayer::Options);
OSGEARTH_SPECIALIZE_CONFIG(osgEarth::CompositeLandCoverLayer::Options);


#endif // OSGEARTH_COMPOSITE_H