/* -*-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_WMS_H
#define OSGEARTH_WMS_H

#include <osgEarth/Common>
#include <osgEarth/ImageLayer>
#include <osgEarth/URI>
#include <osgEarth/TimeControl>
#include <osg/ImageSequence>
#include <set>

namespace osgEarth {
    class WMSImageLayer;
    namespace Util {
        class XmlElement;
    }
}

/**
 * WMS (OGC Web Map Service)
 * https://www.opengeospatial.org/standards/wms
 */

//! WMS namespace contains WMS support classes used to the Layers
namespace osgEarth { namespace WMS
{
    class WMSImageLayerOptions;

    /**
     * WMS style definition
     */
    class OSGEARTH_EXPORT Style : public osg::Referenced
    {
    public:
        //! Constructs a new style
        Style();
        Style(const std::string& name, const std::string& title);

        //! DTOR
        virtual ~Style() { }

        /**
        *Gets the name of the style
        */
	    const std::string& getName() const {return _name;}

        /**
        *Sets the name of the style
        */
        void setName(const std::string &name) {_name = name;}

        /**
        *Gets the title of the style
        */
	    const std::string& getTitle() const {return _title;}

        /**
        *Sets the title of the style
        */
        void setTitle(const std::string &title) {_title = title;}

    protected:
        std::string _name;
        std::string _title;
    };

    /**
     * WMS server layer definition (unrelated to an osgEarth layer)
     */
    class OSGEARTH_EXPORT Layer : public osg::Referenced
    {
    public:
        Layer();

        /** dtor */
        virtual ~Layer() { }

        /**
        *Gets the name of the layer
        */
        const std::string& getName() const {return _name;}

        /**
        *Sets the name of the layer
        */
        void setName(const std::string &name) {_name = name;}

        /**
        *Gets the title of the layer
        */
        const std::string& getTitle() const {return _title;}

        /**
        *Sets the title of the layer
        */
        void setTitle(const std::string &title) {_title = title;}

        /**
        *Gets the abstract of the layer
        */
        const std::string& getAbstract() const {return _abstract;}

        /**
        *Sets the abstract of the layer
        */
        void setAbstract(const std::string &abstract) {_abstract = abstract;}

        /**
        *Gets the lat lon extents of the layer
        */
        void getLatLonExtents(double &minLon, double &minLat, double &maxLon, double &maxLat) const;

        /**
        *Sets the lat lon extents of the layer
        */
        void setLatLonExtents(double minLon, double minLat, double maxLon, double maxLat);

        /**
        *Gets the extents of the layer
        */
        void getExtents(double &minX, double &minY, double &maxX, double &maxY) const;

        /**
        *Sets the extents of the layer
        */
        void setExtents(double minX, double minY, double maxX, double maxY);


        /**A list of Styles*/
        typedef std::vector<Style> StyleList;

        /**
        *Gets this Layer's list of defined Styles
        */
        StyleList& getStyles() {return _styles;}

        /**A list of spatial references*/
        typedef std::set<std::string> SRSList;

        /**
        *Gets this Layer's list of spatial references
        */
        SRSList& getSpatialReferences() {return _spatialReferences;}

        /**A list of Layers*/
        typedef std::vector< osg::ref_ptr<Layer> > LayerList;

        /**
        *Gets this Layer's list of child Layers
        */
        LayerList& getLayers() {return _layers;}

        /**
        *Gets this Layer's parent layer
        */
        Layer* getParentLayer() const {return _parentLayer;}

        /**
        *Sets this Layer's parent layer
        */
        void setParentLayer( Layer* layer ) {_parentLayer = layer;}

        /**
        *Finds the child Layer with the given name.
        *@returns
        *       The Layer with the given name or NULL if not found.
        */
        Layer* getLayerByName(const std::string &name) const;

    protected:
        std::string _name;
        std::string _title;
        std::string _abstract;
        double _minLon, _minLat, _maxLon, _maxLat;
        double _minX, _minY, _maxX, _maxY;
        StyleList _styles;
        SRSList _spatialReferences;

        LayerList _layers;
        Layer* _parentLayer;
    };

    /**
     * WMS Capabilities exposes the available services of a WMS service
     */
    class OSGEARTH_EXPORT Capabilities : public osg::Referenced
    {
    public:
        Capabilities();

        /** dtor */
        virtual ~Capabilities() { }

        /**
        *Gets the WMS capabilities version
        */
        const std::string& getVersion() const {return _version;}

        /**
        *Sets the WMS capabilities version
        */
        void setVersion(const std::string& version) {_version = version;}

        /**A list of supported formats*/
        typedef std::vector<std::string> FormatList;

        /**
        *Gets the list of supported formats
        */
        FormatList& getFormats() {return _formats;}

        /**
        *Gets the Layer's for the Capabilities.
        */
        Layer::LayerList& getLayers() {return _layers;}

        /**
        *Suggests an extension to use for WMS layers defined for the service.
        *This function will analyze the list of formats contained in the Capabilities request
        *and recommend the first format that has an OpenSceneGraph ReaderWriter that can support
        *it's extension.
        *@returns
        *       The suggested extension.
        */
        std::string suggestExtension() const;

        /**
        *Finds the child Layer with the given name.
        *@returns
        *       The Layer with the given name or NULL if not found.
        */
        Layer* getLayerByName(const std::string &name) const;

        //! Finds the child Layer with the given name from a list of layers
        Layer* getLayerByName(const std::string& name, const WMS::Layer::LayerList& layers) const;

    protected:
        FormatList _formats;
        Layer::LayerList _layers;
        std::string _version;
    };

    /**
     * Reads WMS Capabilities from a URL or file
     */
    class OSGEARTH_EXPORT CapabilitiesReader
    {
    public:
        //! Reads WMS caps from a URI. The URI must be complete, to include
        //! the WMS query string (e.g., ?SERVICE=WMS&REQUEST=GetCapabilities etc.)
        //! @param location URI from which to read
        //! @param options I/O options (or NULL)
        static Capabilities* read( const URI& location, const osgDB::Options *options );

        //! Reads WMS caps from a stream.
        static Capabilities* read( std::istream &in );

    private:
        CapabilitiesReader(){}
        CapabilitiesReader(const CapabilitiesReader &cr){}

        static void readLayers(XmlElement* e, Layer* parentLayer, Layer::LayerList& layers);
    };

    /**
     * Driver for direct communicating with a WMS service.
     * It is rarely necessary to use this class directly. Instead, use a
     * WMSImageLayer.
     */
    class Driver : public osg::Referenced
    {
    public:
        //! Construct the WMS driver
	    Driver(
            const WMSImageLayerOptions& myOptions,
            const osgDB::Options* readOptions);

        //! Connect to the WMS service, query capabilities, and prepare the driver
        Status open(
            osg::ref_ptr<const Profile>& profile,
            DataExtentList& out_dataExtents);

        //! Create and return an image for the tile key
        osg::Image* createImage( const TileKey& key, ProgressCallback* progress ) const;

        //! Temporal extent of the data if any
        const DateTimeExtent& getDateTimeExtent() const;

    protected:
        osg::Image* fetchTileImage(
            const TileKey&     key,
            const std::string& extraAttrs,
            ProgressCallback*  progress,
            ReadResult&        out_response ) const;

        osg::Image* createTimeSeriesImage(
            const TileKey& key, 
            ProgressCallback* progress ) const;

        std::string createURI( const TileKey& key ) const;

        const WMSImageLayerOptions* _options;
        const WMSImageLayerOptions& options() const;

        std::string _formatToUse;
        std::string _srsToUse;
        osg::ref_ptr<const Profile> _profile;
        std::string _prototype;
        std::vector<std::string> _timesVec;
        osg::ref_ptr<const osgDB::Options> _readOptions;
        DateTimeExtent _dateTimeExtent;
    };

    /**
     * Serialization options for a WMS image layer.
     */
    class OSGEARTH_EXPORT WMSImageLayerOptions : public ImageLayer::Options
    {
    public:
        META_LayerOptions(osgEarth, WMSImageLayerOptions, ImageLayer::Options);
        OE_OPTION(URI, url);
        OE_OPTION(URI, capabilitiesUrl);
        OE_OPTION(std::string, layers);
        OE_OPTION(std::string, style);
        OE_OPTION(std::string, format);
        OE_OPTION(std::string, wmsFormat);
        OE_OPTION(std::string, wmsVersion);
        OE_OPTION(std::string, srs);
        OE_OPTION(std::string, crs);
        OE_OPTION(bool, transparent);
        OE_OPTION(std::string, times);
        OE_OPTION(double, secondsPerFrame);

        static Config getMetadata();
        virtual Config getConfig() const;

    private:
        void fromConfig( const Config& conf );
    };

} }  // namespace osgEarth::WMS


namespace osgEarth
{
    /**
     * Image layer connected to a WMS service
     */
    class OSGEARTH_EXPORT WMSImageLayer : public ImageLayer
    {
    public:
        typedef WMS::WMSImageLayerOptions Options;

    public:
        META_Layer(osgEarth, WMSImageLayer, Options, ImageLayer, WMSImage);

        //! Base URL for service requests
        void setURL(const URI& value);
        const URI& getURL() const;

        //! Custom capabilibies URL (optional)
        void setCapabilitiesURL(const URI& value);
        const URI& getCapabilitiesURL() const;

        //! Whitespace-separated list of layer names
        void setLayers(const std::string& value);
        const std::string& getLayers() const;

        //! Name of WMS style to request be applied to the data
        void setStyle(const std::string& value);
        const std::string& getStyle() const;

        //! Data format to request (e.g., mime type)
        void setFormat(const std::string& value);
        const std::string& getFormat() const;

        //! Spatial reference to request
        void setSRS(const std::string& value);
        const std::string& getSRS() const;

        //! CRS to request
        void setCRS(const std::string& value);
        const std::string& getCRS() const;

        //! Whether to request a transparent background
        void setTransparent(const bool& value);
        const bool& getTransparent() const;

        //! Comma-separated list of timestamps for experimental WMS-T support
        void setTimes(const std::string& value);
        const std::string& getTimes() const;


    public: // Layer

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

        //! Establishes a connection to the WMS service
        virtual Status openImplementation() override;

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

        //! Date/Time range if this is WMS-T.
        virtual DateTimeExtent getDateTimeExtent() const override;

    protected:

        //! Destructor
        virtual ~WMSImageLayer() { }

    private:
        osg::ref_ptr<osg::Referenced> _driver;
        bool _isPlaying;
    };

} // namespace osgEarth

OSGEARTH_SPECIALIZE_CONFIG(osgEarth::WMSImageLayer::Options);

#endif // OSGEARTH_WMS_H