added safety query before to prevent starting same race again

mainwindow.cpp

@@ -10,7 +10,9 @@
 #include <QObject>
 #include <QShortcut>
 #include <iostream>
+#include <sstream>
 #include <vector>
+
 using std::vector;
 
 MainWindow::MainWindow(QWidget * parent)
@@ -65,6 +67,46 @@ void MainWindow::NewWindowSettings() {
 }
 
 void MainWindow::WindowRennen() {
+
+    // check if a valid racelist has been created
+    // get last race id
+    string statement = "select aktRennen.id_rennen from aktRennen order by "
+                       "id_rennen DESC limit 1";
+
+    try {
+        string raceId =
+            this->db->getData2(statement, 1).at(0).at(0).toStdString();
+        std::stringstream ss;
+        ss << "select count(*) from Zeiten where zeiten.id_rennen like "
+           << raceId;
+        int res = this->db->getData2(ss.str(), 1).at(0).at(0).toInt();
+        if (res > 0) {
+            // current race was raced before
+            QMessageBox msgBox;
+            msgBox.setText(
+                "Aktuelles Rennen wurde bereits gefahren! Trotzdem fahren?");
+            msgBox.setInformativeText("");
+            msgBox.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
+            msgBox.setDefaultButton(QMessageBox::No);
+            int ret = msgBox.exec();
+
+            switch (ret) {
+            case QMessageBox::No:
+                return;
+
+            case QMessageBox::Yes:
+                // do nothing
+                break;
+            default:
+                // should never be reached
+                break;
+            }
+        }
+
+    } catch (std::exception & e) {
+        Q_UNUSED(e);
+    }
+
     this->interfaceRace = new WindowRace(this->db, this);
     this->interfaceRace->show();
     this->interfaceRennliste = new WindowRennliste(this->db, this);