#include <TH2F.h>
#include <TFile.h>
#include <TChain.h>
#include <TROOT.h>
#include <TStyle.h>
#include <TCanvas.h>
#include <TCutG.h>
#include <TString.h>
#include <TObjArray.h>

void PIDCutChecker(TH2F* hist, 
                   TString saveFileName = "PIDCuts.root", 
                   bool isLogz = false
                  ){
   
   printf("================ Graphic Cut Checker for PID ============== \n");
   
   gStyle->SetOptStat("neiou");

   TCanvas * cCutCreator = new TCanvas("cCutCreator", "PID Cut Creator", 100, 100, 800, 800);
   if( !cCutCreator->GetShowToolBar() ) cCutCreator->ToggleToolBar();

   cCutCreator->Update();
   if( isLogz ) cCutCreator->cd()->SetLogz();
   hist->Draw("colz");
   
   TFile * cutFile;
   TCutG * cut = NULL;
   TObjArray * cutList;

   ///===================== load the cutFile and load the cutList

   int numCut = 0;
   cutFile = new TFile(saveFileName, "UPDATE");
   bool listExist = cutFile->GetListOfKeys()->Contains("cutList");
   if( !listExist ) {
      cutList = new TObjArray();
   }else{
      cutList = (TObjArray*) cutFile->FindObjectAny("cutList");
      numCut = cutList->GetLast()+1;
      printf("----- found %d cuts \n", numCut);
      for( int k = 0; k < numCut; k++){
         if( cutList->At(k) != NULL ){
            printf("found a cut at %2d \n", k);
	    cut = (TCutG*) cutList->At(k);
            cut->Draw("same");
         }else{
            printf("     No cut at %2d \n", k);
         }
      }
   }
  cCutCreator->Modified(); cCutCreator->Update();

}