////////////////////////////////////////////////////////////////////
/// \file example_analysis.cc
///
/// \brief Example of how to open and analysis a RAT ntuple file
///
/// \author T Kaptanoglu <tannerk@sas.upenn.edu>
///
/// REVISION HISTORY:\n
///     2019-06-29 T Kaptanoglu - Initial version
///
/// \details
/// Can be run in the root interpreter by doing:
/// $ root
/// root [0] .L example_analysis.cc++
/// root [1] example_analysis("name_of_ntuple_file")
////////////////////////////////////////////////////////////////////
#include <TROOT.h>
#include <TFile.h>
#include <TTree.h>

#include <RAT/DS/Meta.hh>

#include <vector>

// Example datacleaning mask
const ULong64_t ANALYSIS_MASK = 0xFB0000017FFE;

bool is_monte_carlo(char* filename){
  /*
  Check if the file is data or Monte Carlo
  */
  TFile *f = TFile::Open(filename);
  RAT::DS::Meta *m = (RAT::DS::Meta*)f->Get("meta;");
  int currentPass = m->GetCurrentPass();
  std::vector<int> test = m->GetContainsMCFlags();
  bool mC = test[currentPass];

  if(!mC){
    printf("Analyzing data.\n");
  }

  f->Close();
  delete f;
  return mC;
}

double get_counts_meta(char* filename){
  /*
  For Monte Carlo we get the number of simulated events
  from the meta information
  */

  TFile *f = TFile::Open(filename);
  RAT::DS::Meta *m = (RAT::DS::Meta*)f->Get("meta;");
  int currentPass = m->GetCurrentPass();
  std::vector<int> eventsG = m->GetEventsGeneratedCounts();
  int gC = eventsG[currentPass];

  printf("Analyzing %d simulated events.\n", gC);

  f->Close();
  delete f;
  return gC;
}

void example_analysis(char* filename){
  /*
  Open up an ntuple file and perform some analysis.
  @param filename: The name of the ntuple file
  */

  // Open up the data or the MC for analysis
  TFile *f = TFile::Open(filename);
  TTree *t = (TTree*)f->Get("output");

  ULong64_t dataCleaningMask;
  int runID, gtid;
  double energy;
  double posr;
  bool fitValid;

  // Documentation on what is contained within the standard
  // ntuple files can be found here:
  // https://snopl.us/docs/rat/user_manual/html/standard_ntuples.html

  t->SetBranchAddress("dcFlagged", &dataCleaningMask);
  t->SetBranchAddress("runID",&runID);
  t->SetBranchAddress("eventID",&gtid);
  t->SetBranchAddress("energy",&energy);
  t->SetBranchAddress("posr", &posr);
  t->SetBranchAddress("fitValid",&fitValid);

  // Whether or not we have a monte carlo file
  bool isMC = is_monte_carlo(filename);

  // Number of simulated events, for monte carlo
  if(isMC){
    int nCounts = get_counts_meta(filename);
  }

  for(int iEV = 0; iEV < t->GetEntries(); iEV++){

    t->GetEntry(iEV);

    // Apply data-cleaning if we have a data. Do not apply for monte carlo.
    if(!isMC && !((dataCleaningMask & ANALYSIS_MASK) == ANALYSIS_MASK)){
      continue;
    }

    // Check we have a valid fit.
    if(!fitValid){
      continue;
    }

    // Rest of the analysis code
    if(gtid == 0){
      printf("Run %d event %d has energy %.2f MeV and position %.2f mm\n",
             runID, gtid, energy, posr);
    }
  }

  f->Close();
}