//-----------------------------------------------------------------------------
//  Dec 15 1999 P.Murat: 
//  --------------------
//  an example showing how to copy a subset of events from the input ntuple 
//  (UC STNTUPLE 5.x converted to ROOT) to output TStntuple (C++ equivalent of
//  US STNTUPLE)
//
//  the user is supposed to supply a function event_is_ok(THBookStnEvent*)
//  returning 1 if the input event has to be copied into output ntuple and
//  0 otherwise
//-----------------------------------------------------------------------------

#ifndef __CINT__
#include "TROOT.h"
#include "TSystem.h"
#include "TRegexp.h"
#include "TFile.h"
#include "TTree.h"
#include "TInterpreter.h"
#include <Stntuple/THBookStnEvent.hh>
#include <Stntuple/THBookStntuple.hh>
#include <Stntuple/TStntupleEvent.hh>
#include <Stntuple/TStntuple.hh>
#endif

THBookStnEvent* input_event;
TStntupleEvent* output_event;

int book_histograms();
int process_event(TStntupleEvent* event);
int end_job();

double const kDegree = TMath::Pi()/180.;

//-----------------------------------------------------------------------------
//  `dir' - name of the directory with root files, I'm assuming that all the
// *.root files in `dir' produce one chain
//-----------------------------------------------------------------------------
int hbook_loop(const char* dir_name, int first_event=0, int last_event=-1) {

				// define input chain

  input_event  = new THBookStnEvent();
  output_event = new TStntupleEvent();

  book_histograms();

  THBookStntuple* input = new THBookStntuple("/STNTUPLE/h1",input_event);

  void*   dir;
  char    filename[200];
  Ssiz_t  len;

  if (dir = gSystem->OpenDirectory(dir_name)) {
    char* fname;
    while (fname = (char*) gSystem->GetDirEntry(dir)) {
      
      sprintf(filename,"%s/%s",dir_name,fname);
      TRegexp regexp(".root");
      if (regexp.Index(filename,&len,0) > 0) {
	input->Add(filename);
      }
    }
  }
  else {
				// this could be a single file
    TFile f(dir_name);
    if (f.IsOpen()) {
      input->Add(dir_name);
    }
    else {
      printf(" ------------ cant open input file \n");
      return -2;
    }
  }
  
  input->Print();
  input->LoadTree(0);
  input->SetBranches();

  int     ngood = 0;
  int     nbytes;

  double   nentries = input->GetEntries();

  printf("nentries = %5d\n",nentries);

  int ifirst = 0;
  if (first_event > 0) ifirst = first_event;

  int ilast = (int) nentries;
  if (last_event >= 0) ilast = last_event;

  for (Int_t ievent=ifirst; ievent<ilast; ievent++) {

   if (input->LoadTree(ievent) < 0) break;

					// read the event in
    nbytes = input->GetEntry(ievent);
    output_event->InitFromHBook(input_event);
    process_event(output_event);
  }
  
  end_job();

  delete input;

  delete input_event;
  delete output_event;
}