#ifndef OAEMFIELD_IFIELDMAPDESCRIPTION_HXX
#define OAEMFIELD_IFIELDMAPDESCRIPTION_HXX

#include <IFieldDescription.hxx>
#include <TMD5.h>
#include <string>
#include <vector>
#include <TVector3.h>
#include <TRotation.h>

namespace COMET {
    class IFieldMapDescription;
}

/// Implement the FieldDescription for field-map files.
/// Persists the original filename and the MD5 check-sum so that the same field
/// can be loaded back in even the file might not be stored in the same
/// directory.
class COMET::IFieldMapDescription:public COMET::IElementFieldDescription{
    public:
        IFieldMapDescription();
        IFieldMapDescription(const std::string& fieldMapFile,
                Double_t scale, Double_t gradient,
                Double_t timeOffset, TVector3 translation, 
                TRotation rotation);
        virtual ~IFieldMapDescription();

        virtual void ls(Option_t* opt = "") const;

        virtual COMET::IElementField* Recreate()const;

        /// Add a directory to be searched for fieldmaps files.
        /// Entries can contain environment variables (escaped as ${..}), which
        /// will be expanded when searching for files.
        static void AddFieldmapPath(const std::string& path){
            SetupFilePath();
            fFieldmapPaths.insert(fFieldmapPaths.begin(),path);
        }

        /// Print the list of paths that are used to find fieldmaps
        static void PrintFieldmapSearchPaths(bool use_error_stream=false);

    private:
        std::string FindFullFilename()const;
        static void SetupFilePath();

    private:
        std::string fFilename;
        TMD5* fCheckSum;
        Double_t fScaling;
        Double_t fGradient;
        Double_t fTimeOffset;
        TVector3 fTranslation;
        TRotation fRotation;

        /// List of paths that should be searched for fieldmaps.
        /// Entries can contain environment variables
        typedef std::vector<std::string> PathList; //!
        static std::vector<std::string> fFieldmapPaths; //!

        ClassDef(IFieldMapDescription,1);
};

#endif // OAEMFIELD_IFIELDMAPDESCRIPTION_HXX