#include "GeometryDescriptor.hh"
#include "G4System.hh"

#include <iostream>
#include <string>
#include <vector>

int main(int argc, char** argv) {
    int nEvents = 10;

    if (argc > 2) {
        std::cerr << "Usage: run_pbwo4 [nEvents]" << std::endl;
        return 1;
    }
    if (argc == 2) {
        try {
            nEvents = std::stoi(argv[1]);
            if (nEvents <= 0) throw std::invalid_argument("must be positive");
        } catch (const std::exception& e) {
            std::cerr << "Invalid nEvents '" << argv[1] << "': " << e.what() << std::endl;
            return 1;
        }
    }

    std::string outfile = "pbwo4_" + std::to_string(nEvents) + "events_hits.root";

    GeometryDescriptor gd;
    gd.addLayer(20.0, "G4_PbWO4", true, 10, 10);

    G4System g4;
    g4.init(gd, -1);
    g4.run_batch(nEvents, {"e-"}, 1.0, 1.0, outfile);

    std::cout << "Saved " << nEvents << " events to " << outfile << std::endl;
    return 0;
}