/* -*-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 OSGEARTHUTIL_OCEAN
#define OSGEARTHUTIL_OCEAN

#include <osgEarthUtil/Common>
#include <osgEarth/DateTime>
#include <osgEarth/Config>
#include <osgEarth/SpatialReference>
#include <osgEarth/Profile>
#include <osg/Group>
#include <osg/View>
#include <osgDB/ReaderWriter>

namespace osgEarth {
    class MapNode;
}
namespace osgDB {
    class Options;
}

namespace osgEarth { namespace Util 
{
    using namespace osgEarth;

    /**
     * Base Options structure for loading an Ocean node from a plugin.
     */
    class OSGEARTHUTIL_EXPORT OceanOptions : public DriverConfigOptions
    {
    public:
        OceanOptions( const ConfigOptions& options =ConfigOptions() );
        virtual ~OceanOptions() { }
        virtual Config getConfig() const;

        /** Maximum altitude at which the ocean is visible. */
        optional<float>& maxAltitude() { return _maxAltitude; }
        const optional<float>& maxAltitude() const { return _maxAltitude; }

    protected:
        virtual void mergeConfig( const Config& conf );
        
    private:
        void fromConfig( const Config& conf );

        optional<float> _maxAltitude;
    };


    /**
    * Interface for a Node that renders an ocean surface.
    */
    class OSGEARTHUTIL_EXPORT OceanNode : public osg::Group
    {
    public:
        static OceanNode* create(
            MapNode* map);

        static OceanNode* create(
            const OceanOptions&  options,
            MapNode*             map );

    protected:
        // CTOR (abstract base class)
        OceanNode(const OceanOptions& options);

        // SRS for this ocean. Impl class should call this.
        void setSRS(const SpatialReference* srs) { _srs = srs; }
        const SpatialReference* getSRS() { return _srs.get(); }

        // protected DTOR (heap-only)
        virtual ~OceanNode();

    public:

        /** Sets the sea level, as an offset from the ellipsoid (meter) */
        void setSeaLevel(float offsetMeters);
        float getSeaLevel() const { return _seaLevel; }

        /** Sets the alpha of the ocean */
        void setAlpha(float alpha);
        float getAlpha() const { return _alpha; }



    public: // osg::Group

        virtual void traverse(osg::NodeVisitor&);

    protected: // impl class can override these to detect changes

        virtual void onSetSeaLevel() { }

        virtual void onSetAlpha() { }

    private:

        float _seaLevel;
        float _alpha;

        osg::ref_ptr<const SpatialReference> _srs;
        const OceanOptions _options;
    };


    /**
     * Base class for an ocean driver plugin implementation.
     */
    class OSGEARTHUTIL_EXPORT OceanDriver : public osgDB::ReaderWriter
    {
    protected:
        MapNode* getMapNode(const osgDB::Options* opt) const;
        const OceanOptions& getOceanOptions(const osgDB::Options* opt) const;
    };

    /**
     * Factory interface that ocean extensions need to implement. Someday we will
     * convert the ocean extensions into proper NodeKits, at which point this method
     * will probably be no longer necessary since you can just link with the library
     * and create the OceanNode normally.
     */
    class /*header-only*/ OceanNodeFactory
    {
    public:
        virtual OceanNode* createOceanNode(MapNode* mapNode) =0;
    };

} } // namespace osgEarth::Util

#endif //OSGEARTHUTIL_OCEAN
