///////////////////////////////////////////////////////////////////
//////// Go4 GUI example script corrhistos.C
//        H.Essel, gsi, May 2006
// NOTE: to be run in Go4 GUI local command line or in ROOT CINT!
//       NEVER call this script in remote analysis process!!!
/////// Functionality:
// Creates a graph x-y with bin by bin contents of histogram of name1 and histogram of name2.
/////// Usage running in Go4 GUI:
// The draw flag switches if the results are displayed each time this makro is called
// if display is switched off, the result histogram is just updated in browser and existing displays
/////// Usage running in plain ROOT:
// There is one more argument: the name of a root file where the two histograms must be.
// The draw flag switches if the results are displayed each time this makro is called
// if display is switched off, result is lost
///////
#include "Riostream.h"


#ifdef __GO4MACRO__
// Get histograms from GO4 GUI
Bool_t corrhistos(const char *name1, const char *name2, Bool_t draw)
{
   if(!TGo4AbstractInterface::Instance() || go4!=TGo4AbstractInterface::Instance()) {
      std::cout <<"FATAL: Go4 gui macro executed outside Go4 GUI!! returning." << std::endl;
      return kFALSE;
   }
   TString fullname1 = go4->FindItem(name1);
   TObject *ob1=go4->GetObject(fullname1,1000);
   if(!ob1 || !ob1->InheritsFrom("TH1")) {
      std::cout <<"corr could not get histogram "<<fullname1 << std::endl;
      return kFALSE;
   }
   TH1 *his1 = (TH1 *)ob1;
   TString fullname2 = go4->FindItem(name2);
   TObject *ob2=go4->GetObject(fullname2,1000);
   if(!ob2 || !ob2->InheritsFrom("TH1")) {
      std::cout <<"corr could not get histogram "<<fullname2 << std::endl;
      return kFALSE;
   }
   TH1 *his2 = (TH1 *) ob2;
#else
   // Get histograms from file
   Bool_t corrhistos(const char *file, const char *name1, const char *name2, Bool_t draw)
   {
      TFile *f = TFile::Open(file,"r");
      if(!f) {
         std::cout <<"corrhistos could not open file " << file << std::endl;
         return kFALSE;
      }
      TH1 *his1 = f->Get(name1);
      if(!his1) {
         std::cout <<"corrhistos could not get histogram "<< name1 << " in file " << file << std::endl;
         return kFALSE;
      }
      TH1 *his2 = f->Get(name2);
      if(!his2) {
         std::cout <<"corrhistos could not get histogram "<< name2 << " in file " << file << std::endl;
         return kFALSE;
      }
#endif
      TString n1 = his1->GetName();
      TString n2 = his2->GetName();
      TString t1 = his1->GetName();
      TString t2 = his2->GetName();
      TString finalname=n1+"-"+n2;
      TString finaltitle=t1+" x "+t2;
      Int_t nb1=his1->GetNbinsX();
      Int_t nb2=his2->GetNbinsX();
      Int_t n = nb1;
      if(nb1 > nb2) n = nb2;
      TArrayD *x = new TArrayD(n);
      TArrayD *y = new TArrayD(n);
      for (Int_t i = 0; i < n; i++) {
         x->AddAt(his1->GetBinContent(i+1),i);
         y->AddAt(his2->GetBinContent(i+1),i);
      }
      TGraph *result = new TGraph(n,x->GetArray(),y->GetArray());
      result->SetNameTitle(finalname,finaltitle);
      result->SetMarkerColor(4);
      result->SetMarkerSize(0.3);
      result->SetMarkerStyle(20);
      result->SetLineColor(1);

#ifdef __GO4MACRO__
      // save to Workspace folder Correlations
      TString graname = go4->SaveToMemory("Correlations",result,kTRUE);
      // returns full name needed for drawing
      std::cout << graname.Data() << std::endl;
      if(!draw) return kTRUE;
      ViewPanelHandle vpanel = go4->StartViewPanel();
      go4->DrawItem(graname, vpanel, "AP");
#else
      TCanvas *canv=new TCanvas(file,finaltitle,1100,800);
      result->Draw("AP");
      result->GetXaxis()->SetTitle("xxx");
      result->GetYaxis()->SetTitle("yyy");
      result->GetXaxis()->CenterTitle();
      result->GetYaxis()->CenterTitle();
      result->Draw("AP");
      canv->Update();
#endif
      return kTRUE;
   }