#include <iostream.h>
//
//PURPOSE
// Stacks histograms of default, tight, loose electron variables in order to check cuts are being applied correctly
// Produces a ps file containing every 1D histogram in the ElectronBlock sub-directories default/tight/loose
//
//CAVEAT
// Assumes you have used ele_cand.C to analyse a Stntuple with TopEventModule information
// For Stntuples from other sources, switch off tight/loose electron plots
//
//INSTRUCTIONS
// User can just run it with                         .x Stntuple/top/ele_display.C
//
// User can specify a file name as an argument       .x Stntuple/top/ele_display.C("myfile.hbk")
// User can switch off tight/loose electron plots    .x Stntuple/top/ele_display.C("myfile.hbk",0)
// User can switch off log scale plots with          .x Stntuple/top/ele_display.C("myfile.hbk",1,0)
//
//ADVICE
// Open area is for default electrons
// Hatched area is for loose electrons (but my version of ghostview doesn't like this...)
// Solid area is for tight electrons 
//
// Log scale plots: each histogram is displayed twice: 
// LHS pad has linear y scale, RHS pad has logarithmic y scale 
//
// Start root with option -b if you just want to make the postscript file
// and not have to wait impatiently for the screen to update
//
//HOW
// Done by iterating over list of keys of histograms



void ele_display(Char_t* filename="ele_cand.root",  Int_t TopEvent=1, Int_t logPlotToo=1 ){
  
  //Set up the style
  gROOT->SetStyle("Plain");
  gStyle->SetTitleFont(32);  	//Title box font (32=italic times bold)
  gStyle->SetTitleX(0.1);		//Title box x position (top left-hand corner)	
  gStyle->SetTitleY(0.995); 	//Title box y position (default value)		
  gStyle->SetTitleW(0.6);		//Title box width as fraction of pad size
  gStyle->SetTitleH(0.08);	//Title box height as fraction of pad size	
  gStyle->SetOptStat(1111111); //Integral, Overflow, Underflow, RMS, Mean, Nent, Name
  gStyle->SetTickLength(-0.03,"X");
  gStyle->SetTickLength(-0.03,"Y");
  gROOT->ForceStyle();

  //Open the file
  TFile* f=new TFile(filename);
  f->ls();
  
  //Complicated - draw all histograms in a general way!
  //
  //
  //Open a canvas
  TCanvas* myc = new TCanvas("Electrons","Electrons all/tight/loose",500,600);
  myc->Clear();
  myc->Divide(2,4); //Even number of pads, please!
  myc->cd(1);
  
  //Open a postscript file
  printf("My Linux ghostview does not like SetFillStyle, use gs instead! fcdfsgi2 version was ok");
  TPostScript *ps = new TPostScript("electron.ps",111);
  ps->NewPage();
  

  //Get pointers to subdirectories
  f->cd("ElectronBlock/default");
  TDirectory* dirD = gDirectory;
  f->cd("ElectronBlock/tight");
  TDirectory* dirT = gDirectory;
  f->cd("ElectronBlock/loose");
  TDirectory* dirL = gDirectory;

  //You could also access each histogram by name like this
  //const char* histName = "ncem_Et";
  //TH1F* hD = (TH1F*)dirD->Get(histName);
  //TH1F* hT = (TH1F*)dirT->Get(histName);
  //TH1F* hL = (TH1F*)dirL->Get(histName);
  // mydraw1D(hD,hT,hL);

  //Keys method
  //Get iterators to list of histograms in each directory
  TIter nextD(dirD->GetListOfKeys());
  TIter nextT(dirT->GetListOfKeys());
  TIter nextL(dirL->GetListOfKeys());
  
  TKey* keyD;
  TKey* keyT;
  TKey* keyL;
  int ipad =1;
  //while next keys all exist
  while ( (keyD=(TKey*)nextD()) && (keyT=(TKey*)nextT()) && (keyL=(TKey*)nextL()) ) {
    
    printf("\n key: %s points to an object of class: %s at %d",
	   keyD->GetName(),
	   keyD->GetClassName(),keyD->GetSeekKey()
	   );

    if(strcmp(keyD->GetClassName(),"TH1F")==0){ //Check it is a 1D histogram!
      
      TH1F* hD = (TH1F*)dirD->Get(keyD->GetName());
      TH1F* hT = (TH1F*)dirT->Get(keyT->GetName());
      TH1F* hL = (TH1F*)dirL->Get(keyL->GetName());
      
      myc->cd(ipad++);      
      mydraw1D(hD,hT,hL,TopEvent); //Linear y scale
      
      if(logPlotToo==1){ //command line switch
	myc->cd(ipad++);
	mydraw1D(hD,hT,hL,TopEvent,1); //Logarithmic y scale 
      }
    }

    if(ipad==9){//update then clear canvas and go to next page in ps file
      myc->Update();
      myc->Clear(); //Clearing canvas makes a new page in postscript file
      myc->Divide(2,4);
      ipad=1;
    }

  }

  ps->Close();
  
  return;
}

//Stack 3 histograms
//hD is all
//hT is tight
//hL is loose, both is tight+loose
void mydraw1D(TH1F* hD, TH1F* hT, TH1F* hL, Int_t TopEvent=1, Int_t opt=0){

  //log or linear scales?
  if(opt==0){
    gPad->SetLogy(0); //Linear y scale
  }else{
    gPad->SetLogy(1); //Logarithmic y scale
    hD->SetMinimum(0.8);
    hT->SetMinimum(0.8);
    hL->SetMinimum(0.8);
  }

  if(TopEvent==1){
    //make a histogram with tight and loose electrons
    TH1F* both = (TH1F*) hL->Clone();
    both->SetName("both");
    both->Add(hT);
    
    //set fill colours and styles
    both->SetFillColor(4);
    //both->SetFillStyle(3004);
    hT->SetFillColor(5);
    
    //Draw them! Check there is at least one entry in histogram to avoid log scale complaints
    hD->Draw();
    if(both->GetEntries() >0) both->Draw("same");
    if(hT->GetEntries()   >0) hT->Draw("same");
    
    //Add a legend
    leg =new TLegend(0.55,0.75,0.75,0.9,"");
    leg->SetFillColor(0);
    leg->AddEntry(hD,"Default");
    leg->AddEntry(both,"Loose","F");
    leg->AddEntry(hT,"Tight","F");
    leg->Draw();

  }else{
    //just draw default histogram
    hD->Draw();
  }
    
  return;
}