// $Id$
//-----------------------------------------------------------------------
//       The GSI Online Offline Object Oriented (Go4) Project
//         Experiment Data Processing at EE department, GSI
//-----------------------------------------------------------------------
// Copyright (C) 2000- GSI Helmholtzzentrum fuer Schwerionenforschung GmbH
//                     Planckstr. 1, 64291 Darmstadt, Germany
// Contact:            http://go4.gsi.de
//-----------------------------------------------------------------------
// This software can be used under the license agreements as stated
// in Go4License.txt file which is part of the distribution.
//-----------------------------------------------------------------------

#ifndef TGO4FILESOURCE_H
#define TGO4FILESOURCE_H

#include "TGo4EventSource.h"

#include "TString.h"

class TFile;
class TTree;
class TList;
class TGo4FileSourceParameter;
class TGo4EventElement;

/**
 * @brief Raw event source which reads entries from a root TTree in a TFile.
 * @details File is opened by ctor; method BuildEvent() iterates over tree. Needs pointer to external
 * reference to event structure class which must match the structure of the tree entry
 * New since 10/2004: Name of event element defines tree subbranch
 * to be activated as partial input
 * @ingroup go4_event
 * @author J. Adamczewski
 * @since 1/2001
 */
class TGo4FileSource : public TGo4EventSource {

  public:

    TGo4FileSource();

    TGo4FileSource(TGo4FileSourceParameter *par);

    TGo4FileSource(const char *name);

    virtual ~TGo4FileSource();

    /** Fill the destination event dest from the tree.
      * If end of tree is reached, the current event counter
      * is reset and a kFALSE value is returned. */
    Bool_t BuildEvent(TGo4EventElement *dest) override;

    static TList *ProducesFilesList(const char *mask);

  private:

    TFile *fxFile{nullptr}; //!

    TTree *fxTree{nullptr}; //!

    /** Number of events stored in the Tree. Used to check if
      * the complete tree is already read. */
    Long64_t fiMaxEvents{0};

    /** Event number in current tree. */
    Long64_t fiCurrentEvent{0};

    /** Global event number, starting from the first tree. */
    long int fiGlobalEvent{0};   //!

    /** This flag is used for lazy init of tree in Eventbuilding methods. */
    Bool_t fbActivated{kFALSE}; //!

    /** pointer to top branch event */
    TGo4EventElement *fxTopEvent{nullptr}; //!

    /** list of files names */
    TList *fxFilesNames{nullptr}; //!

    /** current name of the file */
    TString fxCurrentFileName;  //!

    /** Open next file from the files list. */
    Bool_t OpenNextFile();

    /** Close currently open file. */
    Bool_t CloseCurrentFile();

  ClassDefOverride(TGo4FileSource,2)
};

#endif //TGO4FILESOURCE_H