#include "TCanvas.h"
#include "ROOT/RCsvDS.hxx"
#include "TFile.h"
#include "TSystem.h"
#include "TApplication.h"


int df014_CSVDataSource()
{
    // Let's first create a RDF that will read from the CSV file.
    // The types of the columns will be automatically inferred.
    //auto fileNameUrl = "http://root.cern.ch/files/tutorials/df014_CsvDataSource_MuRun2010B.csv";
    auto fileName = "df014_CsvDataSource_MuRun2010B_cpp.csv";
    //if (gSystem->AccessPathName(fileName))
    //    TFile::Cp(fileNameUrl, fileName);
    auto df = ROOT::RDF::FromCSV(fileName);

    // Now we will apply a first filter based on two columns of the CSV,
    // and we will define a new column that will contain the invariant mass.
    // Note how the new invariant mass column is defined from several other
    // columns that already existed in the CSV file.
    auto filteredEvents =
        df.Filter("Q1 * Q2 == -1")
        .Define("m", "sqrt(pow(E1 + E2, 2) - (pow(px1 + px2, 2) + pow(py1 + py2, 2) + pow(pz1 + pz2, 2)))");

    // Next we create a histogram to hold the invariant mass values and we draw it.
    auto invMass =
        filteredEvents.Histo1D({ "invMass", "CMS Opendata: #mu#mu mass;#mu#mu mass [GeV];Events", 512, 2, 110 }, "m");

    auto c = new TCanvas();
    c->SetLogx();
    c->SetLogy();
    invMass->DrawClone();

    // We will now produce a plot also for the J/Psi particle. We will plot
    // on the same canvas the full spectrum and the zoom in on the J/psi particle.
    // First we will create the full spectrum histogram from the invariant mass
    // column, using a different histogram model than before.
    auto fullSpectrum =
        filteredEvents.Histo1D({ "Spectrum", "Subset of CMS Run 2010B;#mu#mu mass [GeV];Events", 1024, 2, 110 }, "m");

    // Next we will create the histogram for the J/psi particle, applying first
    // the corresponding cut.
    double jpsiLow = 2.95;
    double jpsiHigh = 3.25;
    auto jpsiCut = [jpsiLow, jpsiHigh](double m) { return m < jpsiHigh && m > jpsiLow; };
    auto jpsi =
        filteredEvents.Filter(jpsiCut, { "m" })
        .Histo1D({ "jpsi", "Subset of CMS Run 2010B: J/#psi window;#mu#mu mass [GeV];Events", 128, jpsiLow, jpsiHigh },
            "m");

    // Finally we draw the two histograms side by side.
    auto dualCanvas = new TCanvas("DualCanvas", "DualCanvas", 800, 512);
    dualCanvas->Divide(2, 1);
    auto leftPad = dualCanvas->cd(1);
    leftPad->SetLogx();
    leftPad->SetLogy();
    fullSpectrum->DrawClone("Hist");
    dualCanvas->cd(2);
    jpsi->DrawClone("HistP");

    return 0;
}

int main(int argc, char** argv)
{
    TApplication app("Root Application", &argc, argv);
    df014_CSVDataSource();
    app.Run();
	return 0;
}