#ifndef TMidasFile_hxx_seen
#define TMidasFile_hxx_seen

#include <string>

#include <Rtypes.h>
#include <zlib.h>

#include "IVInputFile.hxx"

namespace COMET {
    class IMidasEventParser;
    class IMidasFile;
    class ICOMETRawEvent;
}
/// Acknowledgements: This class derives from, and is almost identical to,
/// the class of the same name developed by
///
///   Stefan Ritt, Pierre-Andre Amaudruz and Konstantin Olchanski
///
/// in the rootana package which is part of the Midas Data
/// Acquisition:-
///
///     https://midas.psi.ch/
///
/// The code was extracted from revision 55 of Subversion repository:-
///
///      svn://ladd00.triumf.ca/rootana/trunk rootana
///
/// The T2K group should monitor changes to that code looking for enhancements
/// and should report back any code improvements we make to Konstantin.
///
/// Last checked rootana revision: 66.
///
/// IMidasFile is a class that can sequentially read a MIDAS .mid file using C
/// I/O and return a ICOMETRawEvent using the method:-
///
///   COMET::ICOMETRawEvent* IMidasFile::ReadRawEvent()
///
/// The current implementation first fills a IMidasEventParser, which is
/// another class derived from rootana, using the
///
///   bool Read(IMidasEventParser *event);
///
/// method and then uses the ICOMETRawEvent(IMidasEventParser&) constructor.

class  COMET::IMidasFile : public COMET::IVInputFile
{
public:
    /// default constructor
    IMidasFile();
    /// destructor
    virtual ~IMidasFile();

    /// Open input file
    bool Open(const char* filename);

    /// Close input file
    void Close();

    /// Read one event from the file
    ICOMETRawEvent* ReadRawEvent();

    /// Get the name of this file
    const char* GetFilename()  const { return fFilename.c_str();  }

    /// Get error value for the last file error
    int         GetLastErrno() const { return fLastErrno; }

    /// Get error text for the last file error
    const char* GetLastError() const { return fLastError.c_str(); }

    /// Return the first event in the input file.  If the file does not
    /// support rewind, then this should throw an exception if it is called a
    /// second time.
    virtual COMET::ICOMETEvent* FirstEvent();

    /// Get the next event from the input file.  If skip is greater than zero,
    /// then skip this many events before returning.
    virtual COMET::ICOMETEvent* NextEvent(int skip=0);

    /// Return the position of the event just read inside of the file.  A
    /// position of zero is the first event.  After reading the last event,
    /// the position will be the total number of events in the file.
    virtual int GetPosition(void) const;

    /// Flag that the file is open.
    virtual bool IsOpen();

    /// Flag that the end of the file has been reached.
    virtual bool EndOfFile() {return fEndOfFile;}

    /// Close the input file.
    virtual void CloseFile() {Close();}

protected:

    /// Internal method to read one event from the file into IMidasEventParser
    bool Read(COMET::IMidasEventParser *event);

    /// name of the currently open file
    std::string fFilename;

    /// errno from the last operation
    int         fLastErrno;
    /// error string from last errno
    std::string fLastError;

    /// "true" if file has to be byteswapped
    bool fDoByteSwap;

    /// open file descriptor used for uncompressed files
    int         fFile;
    /// zlib compressed file reader
    gzFile      fGzFile;

    /// The end of file has been found.
    bool fEndOfFile;

    /// The number of events read from the file.
    int fEventsRead;

    ClassDef(IMidasFile,0)
};

#endif // TMidasFile_hxx_seen