/* -*-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 OSGEARTHSYMBOLOGY_RESOURCE_LIBRARY_H
#define OSGEARTHSYMBOLOGY_RESOURCE_LIBRARY_H 1

#include <osgEarth/Common>
#include <osgEarth/Skins>
#include <osgEarth/InstanceResource>
#include <osgEarth/ModelResource>
#include <osgEarth/ModelSymbol>
#include <osgEarth/Threading>
#include <osgEarth/Random>
#include <map>

namespace osgEarth { namespace Util
{
    /** 
     * ResourceLibrary manages a collection of external resources that a
     * build system can use the construct geometries.
     */
    class OSGEARTH_EXPORT ResourceLibrary : public osg::Referenced
    {
    public:
        /**
         * Creates a new resource library with a source URI. The library
         * will populate upon first use..
         */
        ResourceLibrary( 
            const std::string& name, 
            const URI&         uri);

        /**
         * Creates a new resource library from a config.
         */
        ResourceLibrary( const Config& conf );


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

        /** 
         * Initialize the catalog by loading its contents into memory
         */
        bool initialize( const osgDB::Options* options );

        /**
         * Gets the name of the lib.
         */
        const std::string& getName() const { return _name; }
        void setName(const std::string& name) { _name = name; }

        /**
         * Adds a resource to the library.
         */
        void addResource( Resource* resource );

        /**
         * Removes a resource from the library.
         */
        void removeResource( Resource* resource );


    public: // Skin resource functions

        /**
         * Finds and returns a Skin resource by name.
         */
        SkinResource* getSkin( const std::string& name, const osgDB::Options* dbOptions =0L ) const;

        /**
         * Returns a list of all Skin resources.
         */
        void getSkins( SkinResourceVector& output, const osgDB::Options* dbOptions =0L ) const;

        /**
         * Returns a list of all Skin resources that match the criteria specified
         * in the symbol.
         */
        void getSkins( const SkinSymbol* symbol, SkinResourceVector& output, const osgDB::Options* dbOptions =0L ) const;

        /**
         * Returns a skin that matches the criteria specified in the symbol. The method
         * will randomly select a suitable skin if there are more than one match.
         */
        SkinResource* getSkin( const SkinSymbol* symbol, unsigned int rand, const osgDB::Options* dbOptions =0L ) const;


    public: // Instance functions

        /**
         * Finds an instance-resource by name.
         */
        InstanceResource* getInstance( const std::string& name, const osgDB::Options* dbOptions =0L ) const;
        
        ModelResource* getModel( const ModelSymbol* ms, const osgDB::Options* dbOptions =0L ) const;

        /**
         * Returns a list of all Model resources.
         */
        void getModels( ModelResourceVector& output, const osgDB::Options* dbOptions =0L ) const;
        
        /**
         * Returns a list of models that match the input symbol.
         */
        void getModels(const ModelSymbol* ms, ModelResourceVector& output, const osgDB::Options* dbOptions =0L) const;

    public: // serialization functions

        void mergeConfig( const Config& conf );
        Config getConfig() const;

        optional<URI>& uri() { return _uri; }
        const optional<URI>& uri() const { return _uri; }

    protected:
        // NB: this must be a std::map (not an unordered_map) because the selection
        // logic iterates over the collection, and the iteration order needs to be
        // constant across implementations (platforms).
        template<typename T> struct ResourceMap : public std::map<std::string, osg::ref_ptr<T> > { };

        optional<URI>                      _uri;
        std::string                        _name;
        bool                               _initialized;
        mutable Threading::ReadWriteMutex  _mutex;

        ResourceMap<SkinResource>          _skins;
        ResourceMap<InstanceResource>      _instances;

        bool matches( const SkinSymbol* symbol, SkinResource* skin ) const;
    };
} }

#endif // OSGEARTHSYMBOLOGY_RESOURCE_LIBRARY_H