/* -*-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.
*
* 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_LINEOFSIGHT
#define OSGEARTHUTIL_LINEOFSIGHT

#include <osgEarth/LineOfSight>
#include <osgEarth/MapNode>
#include <osgEarth/MapNodeObserver>
#include <osgEarth/Terrain>
#include <osgEarth/GeoData>
#include <osgEarth/Draggers>

namespace osgEarth { namespace Contrib
{
    using namespace osgEarth;

    /**
     * A Node that can be used to display radial line of sight calculations
     */
    class OSGEARTH_EXPORT RadialLineOfSightNode : public LineOfSightNode, public MapNodeObserver
    {
    public:
        /**
         * Create a new RadialLineOfSightNode
         * @param mapNode
         *        The MapNode this RadialLineOfSightNode is operating on.
         */
        RadialLineOfSightNode( MapNode* mapNode );

        virtual ~RadialLineOfSightNode();

        /**
         * Sets the radius in meters
         */
        void setRadius( double radius );
        
        /**
         * Gets the radius in meters
         */
        double getRadius() const;

        /**
         * Sets the number of spokes in the radial line of sight calculation
         */
        void setNumSpokes( int numSpokes );

        /**
         * Gets the number of spokes in the radial line of sight calculation
         */
        int getNumSpokes() const;

        /**
         * Gets the center point in world coordinates
         */
        const osg::Vec3d& getCenterWorld() const;

        /**
         * Gets the center point
         */
        const GeoPoint& getCenter() const;

        /**
         * Set the center point.  The point should be in the Map's coordinate system.  So if you're dealing with a geocentric map
         * the location should be in the form lon, lat, elevation
         */
        void setCenter(const GeoPoint& center);

        /**
         * Sets the good color
         */
        void setGoodColor( const osg::Vec4f &color );

        /**
         * Gets the good color
         */
        const osg::Vec4f& getGoodColor() const;


        /**
         * Sets the bad color
         */
        void setBadColor( const osg::Vec4f &color );

        /**
         * Gets the bad color
         */
        const osg::Vec4f& getBadColor() const;

        /**
         * Sets the outline color
         */
        void setOutlineColor( const osg::Vec4f &color );

        /**
         * Gets the outline color
         */
        const osg::Vec4f& getOutlineColor() const;

        /**
         * Gets the display mode
         */
        LineOfSight::DisplayMode getDisplayMode() const;

        /*
         * Sets the display mode
         */
        void setDisplayMode( LineOfSight::DisplayMode displayMode );

        /**
         * Gets whether to draw the fill of this RadialLineOfSightNode
         */
        bool getFill() const;

        /*
         * Sets whether to draw the fill of this RadialLineOfSightNode
         */
        void setFill( bool fill );


        void addChangedCallback( LOSChangedCallback* callback );
        
        void removeChangedCallback( LOSChangedCallback* callback );


        /**
         * Called when the underlying terrain has changed.
         */
        void terrainChanged( const osgEarth::TileKey& tileKey, osg::Node* terrain );
        

        bool getTerrainOnly() const;
        void setTerrainOnly( bool terrainOnly );


    public: // MapNodeObserver

        virtual void setMapNode( MapNode* mapNode );

        MapNode* getMapNode() { return _mapNode.get(); }


    private:
        osg::Node* getNode();
        void compute(osg::Node* node);
        void compute_line(osg::Node* node);
        void compute_fill(osg::Node* node);
        int _numSpokes;
        double _radius;

        LineOfSight::DisplayMode _displayMode;    
        bool _fill;
        osg::Vec4 _goodColor;
        osg::Vec4 _badColor;
        osg::Vec4 _outlineColor;
        GeoPoint   _center;        
        osg::Vec3d _centerWorld;
        osg::observer_ptr< MapNode > _mapNode;        
        LOSChangedCallbackList _changedCallbacks;        
        osg::ref_ptr < osgEarth::TerrainCallback > _terrainChangedCallback;
        bool _terrainOnly;
    };

    /**********************************************************************/

     /**
     * An update callback that allows you to attach a RadialLineOfSightNode to a moving node.
     * The update callback will update the center point of the calcuation to follow the node.
     *
     * Example:
     * RadialLineOfSightNode* los = new RadialLineOfSightNode(myMapNode);
     * los->setUpdateCallback( new RadialLineOfSightTether( myNode ) );
     */
    class OSGEARTH_EXPORT RadialLineOfSightTether : public osg::NodeCallback
    {
    public:
        RadialLineOfSightTether(osg::Node* node);
        virtual ~RadialLineOfSightTether() { }
        virtual void operator()(osg::Node* node, osg::NodeVisitor* nv);  

        osg::Node* node() { return _node.get(); }

    private:
        osg::ref_ptr< osg::Node > _node;
    };


    /**********************************************************************/

    class OSGEARTH_EXPORT RadialLineOfSightEditor : public osg::Group
    {
    public:
        /**
         * Create a new RadialLineOfSightEditor
         * @param los
         *        The RadialLineOfSightNode to edit
         */
        RadialLineOfSightEditor(RadialLineOfSightNode* los);    
        virtual ~RadialLineOfSightEditor();

         /**
         *Updates the position of the dragger to represent the actual location of the RadialLineOfSightNode.
         *This should be called if the los is changed outside of the editor and would probably benefit
         *from the RadialLineOfSightNode having a callback that notifies listeners that the start/end points have changed.
         */
        void updateDraggers();
    private:
        osg::ref_ptr< RadialLineOfSightNode > _los;
        osgEarth::Dragger* _dragger;
        osg::ref_ptr< LOSChangedCallback > _callback;
    };



} } // namespace osgEarth::Tools

#endif // OSGEARTHUTIL_LINEOFSIGHT