//forward declaration
void loop_over_nodes(TObjArray*, TString&, std::map<TString, TVector3> & );

void create_positionlist_plus4(TString inFileName="") 
{

  if (inFileName.Length() > 0 ) {
    cout << "Open file " << inFileName << endl;
    TFile* f = new TFile(inFileName);
    if ( ! f->IsOpen() ) {
      std::cout << "create_tgeonode_list: geometry file " << inFileName << " is not accessible!" << std::endl;
      return;
    }
    gGeoManager = (TGeoManager*) f->Get("FAIRGeom"); 
  }

  std::map<TString, TVector3>  matlist;

  TGeoNode* topNode = gGeoManager->GetTopNode();
  TString Path{"/top_1/"};
  TObjArray* nodes = topNode->GetNodes();
  if ( 1 != nodes->GetEntriesFast()) {
    std::cerr << "There should be only one node in the top node which is the detector keeping volume" << std::endl; 
    return;
  }
  TGeoNode* node = static_cast<TGeoNode*>(nodes->At(0));
  TString TopNodeName{node->GetName()};
  // Replace the trailing _1 by _0 which is the correct number in the full geometry
  //  TopNodeName.Replace(TopNodeName.Length()-1,1,"0");
  Path = Path + TopNodeName + "/";

  std::cout << "{\""<< Path << "\", \"" << node->GetMedium()->GetName() << "\"}," << std::endl;

  gGeoManager->cd(Path);
  TGeoMatrix *globalmatrix = gGeoManager->GetCurrentMatrix();

  Double_t local[3]{0., 0., 0.};
  Double_t global[3]{0., 0., 0.};
  globalmatrix->LocalToMaster(local, global);

  matlist[Path] = TVector3(global[0], global[1], global[2]);

  TObjArray* detectornodes = node->GetNodes();
  loop_over_nodes(detectornodes, Path, matlist);

  ofstream myfile;
  myfile.open ("example.txt");
  for (auto& info: matlist) {
    std::cout << info.first << ", " << info.second.X() << ", "
              << info.second.Y() << ", " << info.second.Z() + 4.0 << std::endl;
    myfile    << info.first << ", " << info.second.X() << ", "
              << info.second.Y() << ", " << info.second.Z() + 4.0 << "\n";    
// original
//    std::cout << info.first << ", " << info.second.X() << ", "
//              << info.second.Y() << ", " << info.second.Z() << std::endl;
//    myfile    << info.first << ", " << info.second.X() << ", "
//              << info.second.Y() << ", " << info.second.Z() << "\n";    
  }
  myfile.close();

  RemoveGeoManager();
}

void loop_over_nodes(TObjArray* nodes, TString& path, std::map<TString, TVector3>& matlist) 
{
  for (Int_t iNode = 0; iNode < nodes->GetEntriesFast(); iNode++) {
    TGeoNode* node = static_cast<TGeoNode*>(nodes->At(iNode));
    TString Fullpath = path + node->GetName() +"/";

    gGeoManager->cd(Fullpath);
    TGeoMatrix *globalmatrix = gGeoManager->GetCurrentMatrix();

    Double_t local[3]{0., 0., 0.};
    Double_t global[3]{0., 0., 0.};
    globalmatrix->LocalToMaster(local, global);

    matlist[Fullpath] = TVector3(global[0], global[1], global[2]);

    TObjArray* subnodes = node->GetNodes();
    if (nullptr != subnodes) {
      loop_over_nodes(subnodes, Fullpath, matlist);
    }
  }
}