#include "ROOT/RDataFrame.hxx"
#include "ROOT/RVec.hxx"
#include "TTree.h"
#include "TFile.h"
#include "TMath.h"
#include <iostream>

using namespace std;

using namespace ROOT;
using namespace ROOT::VecOps;

RVec< RVec<unsigned int> > distinct_comb(unsigned int n)
{
    //cout <<"Entities "<<  n << endl;
    RVec<unsigned int> idx1;
    idx1.reserve(n*(n-1)/2);
    RVec<unsigned int> idx2;
    idx2.reserve(n*(n-1)/2);

    unsigned int ij=0;
    for (unsigned int i=0; i<n-1; i++)
        for (unsigned int j=i+1; j<n; j++)
        {
            idx1.emplace_back(i);
            idx2.emplace_back(j);
        }

    RVec< RVec<unsigned int> > res;
    res.emplace_back(idx1);
    res.emplace_back(idx2);

    return res;

}

void simpletest()
{
   RVec<float> v {2., 3., 1.};
   auto vTaken = Take(v, {0,2,2});
   cout << vTaken << endl;

   RVec<float> v2 {10., 20., 30., 40.};
   auto comb = Combinations(v, v2);
   for (auto acomb: comb)
   {
       cout << acomb << endl;
   }
   auto res = Take(v, comb[0]) - Take(v2, comb[1]);
   cout << res << endl;

   cout << distinct_comb(3) << endl;
   auto dis_comb = distinct_comb(v2.size());

   auto res2 = Take(v2, dis_comb[0]) - Take(v2, dis_comb[1]);
   cout << res2 << endl;

}

void combinator()
{
   TFile f("08FB417A-DC0B-E811-80D7-0CC47A13D110.root");
   TTree *ttree = dynamic_cast<TTree *>(f.Get("Events"));

   RDataFrame rd(*ttree);

   ROOT::RDF::RNode rlm(rd);
   rlm = rlm.Filter("nJet>=7");
   rlm = rlm.Define("dis_comb", ::distinct_comb, {"nJet"});
   rlm = rlm.Define("jphi1", "ROOT::VecOps::Take(Jet_phi, dis_comb[0])");
   rlm = rlm.Define("jphi2", "ROOT::VecOps::Take(Jet_phi, dis_comb[1])");
   rlm = rlm.Define("dphijets", "ROOT::VecOps::abs(ROOT::VecOps::DeltaPhi(jphi1, jphi2))"); 
   rlm = rlm.Define("dphijets_min", "ROOT::VecOps::Min(dphijets)");
   auto histojets = rlm.Histo1D({"dphi", "deltaphi of jets", 50, 0.0, TMath::Pi()}, "dphijets");
   auto histojetsmin = rlm.Histo1D({"dphimin", "min deltaphi of jets", 50, 0.0, TMath::Pi()}, "dphijets_min");

   auto _outrootfile = new TFile("testtest.root", "RECREATE");
   histojets->Write();
   histojetsmin->Write();
   _outrootfile->Write(0, TObject::kOverwrite);
   _outrootfile->Close();


}