////////////////////////////////////////////////////////////////////////
/// \class RAT::DU::DSReader
///
/// \brief Convenience class for ROOT scripts
///
/// \author Stan Seibert <volsung@physics.utexas.edu>
/// \author P G Jones <p.g.jones@qmul.ac.uk>
/// \author J R Wilson <j.r.wilson@qmul.ac.uk> -- contact person
///
/// REVISION HISTORY:\n
///     20/07/2011 : P G Jones - Added methods to return the Run object.\n
///     2014-03-26 : P G Jones - Refactor for ds review, moved from src/io.\n
///     2014-12-16 : J Walker - Add method to get Meta information. \n
///     2015-27-05 : N Barros - Add initialization of run in the DB with runID. \n
///     2017-15-05 : N Barros - Changed DSReader to load RATDB default plane lock if input file
///                             is either data, or run number is not 0
///
/// \details This is the recommended/best way to read a RAT::DS root file.
/// Use as follows,
/// @verbatim
/// DSReader dsReader("filename.root");
///
/// for( size_t iEntry = 0; iEntry < dsReader.GetEntryCount(); iEntry++ )
///   {
///     RAT::DS::Entry rDS = dsReader.GetEntry( iEntry );
///     RAT::DS::Run rRun = dsReader.GetRun();
///   }
/// @endverbatim
///
////////////////////////////////////////////////////////////////////////
#ifndef __RAT_DU_DSReader___
#define __RAT_DU_DSReader___

#include <TObject.h>
#include <TChain.h>
#include <string>
#include <vector>

namespace RAT
{
namespace DS
{
  class Entry;
  class Run;
  class Meta;
}
namespace DU
{

class DSReader : public TObject
{
public:
  /// Construct the DSReader with a filename (inc path)
  ///
  /// @param[in] filename to open
  /// @param[in] useMeta to configure DB or ignore it?
  DSReader( const std::string& filename, const bool useMeta=true );

  /// Construct the DSReader with many files to TChain together
  ///
  /// @param[in] filenames to open
  /// @param[in] useMeta to configure DB or ignore it?
  DSReader( const std::vector<std::string>& filenames, const bool useMeta=true );

  /// Destruct the DSReader, delete TTrees etc...
  ~DSReader();

  /// Called whenever the run changes
  void BeginOfRun();

  /// Add a new file to the total (should restart any loops!)
  ///
  /// @param[in] filename to add
  void Add( const std::string& filename );

  /// Get the entry at index entry
  ///
  /// @param[in] entry index of the entry to return
  /// @return a constant reference to the entry
  /// @throws DataNotFound if entry is out of range
  const DS::Entry& GetEntry( const size_t entry );

  /// Get the count of entries
  ///
  /// @return the total number of entries
  size_t GetEntryCount() const { return fTotalEntries; }

  /// Get the run.
  ///
  /// @return a constant reference to the run
  const DS::Run& GetRun();

  /// Get the run with run ID
  ///
  /// @param[in] runID runID to find
  /// @return a constant reference to the run
  /// @throws DataNotFound if not appropriate run can be found
  const DS::Run& GetRunByRunID( const unsigned int runID );

  /// Get the run with index
  ///
  /// @param[in] index of the run to return
  /// @return a constant reference to the run
  /// @throws DataNotFound if index is out of range
  const DS::Run& GetRunByIndex( const size_t index );

  /// Get the count of runs
  ///
  /// @return the total number of runs
  size_t GetRunCount() const { return fTotalRuns; }

  /// Get the Meta information
  ///
  /// @return a constant reference to the Meta information
  const DS::Meta& GetMeta() const { return *fMeta; }

  // This ROOT macro adds dictionary methods to this class.
  // The number is 0 as this class is never, and should never be written to disc.
  // It assumes this class has no virtual methods, use ClassDef if change this.
  ClassDefNV(DSReader, 2);
protected:
  TChain* fT; ///< The DS T Tree
  TChain* fRunT; ///< The DS runT Tree
  DS::Entry* fDS; ///< The current entry
  DS::Run* fRun; ///< The current run
  DS::Meta* fMeta; ///< The current Meta information
  ULong64_t fCurrentEntry; ///< The current entry index
  ULong64_t fTotalEntries; ///< The total number of entries
  ULong64_t fCurrentRun; ///< The current run index
  ULong64_t fTotalRuns; ///< The total number of runs

  bool fUseMeta; ///< Flag to use or ignore Meta information in file. Default true.
};

} // namespace DU

} // namespace RAT

#endif