#include <iostream>
#include <fstream>
#include "TFile.h"
#include "TTree.h"
#include "TBranch.h"
#include "TEventList.h"


void thinGrid(string strInFile, string strBranchNameTxt = "bNames.txt", int dpdType=1,string strOutFile = "_thin.root"){
  

  std::string argStr;
  std::ifstream ifs(strInFile.c_str());
  std::getline(ifs,argStr);
  // split by ','
  std::vector<std::string> fileList;
  for (size_t i=0,n; i <= argStr.length(); i=n+1)
    {
      n = argStr.find_first_of(',',i);
      if (n == string::npos)
        n = argStr.length();
      string tmp = argStr.substr(i,n-i);
      fileList.push_back(tmp);
    }
  
    
  for (int nFile=0; nFile < fileList.size();nFile++){
  
    TFile *oldfile = TFile::Open(fileList[nFile].c_str());
  

    if (!oldfile || oldfile->IsZombie()) {
      cout << "Could not read: " << strInFile.c_str() << " skipping file..." << endl;
    }
    else{
      string strThinCut = "";
      if (dpdType == 1) {
	strThinCut = "((mu_staco_n > 0  && mu_staco_pt[0]>10000)||(mu_muid_n > 0  && mu_muid_pt[0]>10000)) && el_n > 0 && el_pt>10000";
	//strThinCut = "((mu_staco_n > 0  )||(mu_muid_n > 0  )) && el_n > 0";
      } else {
	strThinCut = "mu_n > 0 && el_n > 0";
      }
    

      TTree *oldtree = (TTree*)oldfile->Get("physics");
      //TTree *oldctree = (TTree*)oldfile->Get("CollectionTree");
      
      oldtree->SetBranchStatus("*",0);    
      cout << "Opening branch names: " << strBranchNameTxt << endl;
      ifstream bNames (strBranchNameTxt.c_str());
      
      while (!bNames.eof()){
	string line;
	getline (bNames,line);
	if(line!=""){
	  oldtree->SetBranchStatus(line.c_str(),1);
	}
      }
    
    
      //Create a new file + a clone of old tree in new file
      TFile *newfile = new TFile(strOutFile.c_str(),"UPDATE");
      TTree *newtree = oldtree->CloneTree(0);
      //TTree *newctree = oldctree->CloneTree();
    

      TEventList *evlist=new TEventList("evlist");
      //int evPassed=oldtree->Draw(">>evlist",strThinCut.c_str());
      oldtree->Draw(">>evlist",strThinCut.c_str());
      int evPassed=evlist->GetN();
      cout << "Number of events after thining: " << evPassed << endl;
    

      for(int i=0;i<evPassed;i++){
	oldtree->GetEntry(evlist->GetEntry(i));
	newtree->Fill();
      }//for i
    
      //newtree->Print();
      newfile->Write();
      delete oldfile;
      delete newfile;   
    }
  }

}