add delete option and error handling to tours

src/tour_list.vala

@@ -174,7 +174,51 @@ namespace Sernatur {
 				}
 			}
 			else if (button == delete_tour) {
-				print ("Delete tour clicked\n");
+				var msg = new Gtk.MessageDialog (this,
+					Gtk.DialogFlags.MODAL,
+					Gtk.MessageType.ERROR,
+					Gtk.ButtonsType.YES_NO,
+					dgettext(null, "Are you sure you wish to delete this tour?"));
+				msg.response.connect ((response_id) => {
+					switch (response_id) {
+						case Gtk.ResponseType.YES:
+							try {
+								Gtk.TreeModel model;
+								Gtk.TreeIter iter;
+								Tour tour;
+								if (selection.get_selected (out model, out iter)) {
+									model.get (iter,
+										Column.TOUR, out tour);
+									Tour.delete_tour (conn.db, tour);
+								}
+							}
+							catch (DBError e) {
+								if (e.code == 1) {
+									var msg2 = new Gtk.MessageDialog (this,
+										Gtk.DialogFlags.MODAL,
+										Gtk.MessageType.ERROR,
+										Gtk.ButtonsType.CLOSE,
+										dgettext(null, "Error: Could not delete tour because there are still associated arrival and departure dates and times!"));
+									msg2.response.connect ((response_id) => {
+										msg2.destroy ();
+									});
+									msg2.set_title (dgettext (null, "Error"));
+									msg2.show ();
+								}
+								else {
+									#if DEBUG
+										error (e.message);
+									#else
+										warning (e.message);
+									#endif
+								}
+							}
+							break;
+					}
+					msg.destroy ();
+				});
+				msg.set_title (dgettext (null, "Error"));
+				msg.show ();
 			}
 			else if (button == close_tour) {
 				this.close ();