public static CalendarDateTime Add(CalendarDateTime x, Duration y)
{
if (y is CalendarDateTimeDuration)
{
return Add(x, (CalendarDateTimeDuration)y);
}
if (y is OrdinalDateTimeDuration)
{
return Add(x, ((OrdinalDateTimeDuration)y).ToCalendarDateTimeDuration());
}
if (y is CalendarDateDuration)
{
return Add(x, (CalendarDateDuration)y);
}
if (y is OrdinalDateDuration)
{
return Add(x, ((OrdinalDateDuration)y).ToCalendarDateDuration());
}
if (y is TimeDuration)
{
return Add(x, (TimeDuration)y);
}
if (y is DesignatedDuration)
{
return Add(x, (DesignatedDuration)y);
}
throw new InvalidOperationException($"A {y.GetType()} cannot be added to a {x.GetType()}.");
}
internal static TimeSpan Subtract(CalendarDateTime later, TimePoint earlier)
{
if (earlier is CalendarDateTime)
{
return later - (CalendarDateTime)earlier;
}
if (earlier is OrdinalDateTime)
{
return later - ((OrdinalDateTime)earlier).ToCalendarDateTime();
}
if (earlier is WeekDateTime)
{
return later - ((WeekDateTime)earlier).ToCalendarDateTime();
}
if (earlier is CalendarDate)
{
return later - (CalendarDate)earlier;
}
if (earlier is OrdinalDate)
{
return later - ((OrdinalDate)earlier).ToCalendarDate();
}
if (earlier is WeekDate)
{
return later - ((WeekDate)earlier).ToCalendarDate();
}
if (earlier is Time)
{
return later - (Time)earlier;
}
throw new InvalidOperationException($"A {earlier.GetType()} cannot be subtracted from a {later.GetType()}");
}