public async Task <Attendee> AddAttendee(string fullName, string email, int?age, string phone,
string residentialAddress, Gender?gender, bool returnedInLastTenDays, bool liveWithCovidCaregivers,
bool caredForSickPerson, MultiChoice?haveCovidSymptoms, int?seatNumber)
{
var normalizedEmail = email?.ToLowerInvariant();
var attendee = new Attendee(normalizedEmail, fullName, age, phone, residentialAddress, gender,
returnedInLastTenDays, liveWithCovidCaregivers, caredForSickPerson, haveCovidSymptoms);
if (seatNumber.HasValue)
{
attendee.UpdateSeatNumber(seatNumber);
}
if (!attendee.CanRegister())
{
throw new InvalidOperationException("You cannot reserve a seat at this time.");
}
await attendee.SaveAsync();
return(attendee);
}