public static string OverlappingReservationsExist(Reservation reservation, IReservationRepo _repository)
{
if (reservation.Status == "Cancelled")
{
return(string.Empty);
}
var reservations = _repository.GetActiveReservations(1);
var overlappingReservation =
reservations.FirstOrDefault(
b =>
reservation.ArrivalDate < b.DepartureDate && b.ArrivalDate < reservation.DepartureDate);
return(overlappingReservation == null ? string.Empty
: overlappingReservation.Reference);
}