/// <summary>
/// Adds the given calendar day and returns one or more new calendar entities representing the new data.
/// </summary>
/// <returns></returns>
public static IEnumerable <Calendar> Add(this Calendar calendar, DateTime day)
{
if (calendar.CoversDate(day))
{ // no work needs to be done.
return(new Calendar[] { calendar });
}
// naively add another calendar entity representing one day.
if ((calendar.EndDate - calendar.StartDate).Days <= 7 &&
calendar.StartDate <= day &&
calendar.EndDate >= day)
{
var newCalendar = new Calendar()
{
EndDate = calendar.EndDate,
StartDate = calendar.StartDate,
Mask = calendar.Mask,
ServiceId = calendar.ServiceId
};
newCalendar.Set(day, true);
return(new Calendar[] { newCalendar });
}
return(new Calendar[] { calendar, day.CreateCalendar(calendar.ServiceId) });
}
/// <summary>
/// Subtracts the given calendar day and returns one or more new calendar entities representing the same data.
/// </summary>
public static IEnumerable <Calendar> Subtract(this Calendar calendar, DateTime day)
{
if (!calendar.CoversDate(day))
{ // no work needs to be done.
return(new Calendar[] { calendar });
}
var firstDayOfWeek = day.FirstDayOfWeek();
var lastDayOfWeek = day.LastDayOfWeek();
if (firstDayOfWeek <= calendar.StartDate &&
lastDayOfWeek >= calendar.EndDate)
{ // yay! this is exceptional but let's take advantage of this.
calendar[day.DayOfWeek] = false;
return(new Calendar[] { calendar });
}
// possibly split in two or three pieces.
if (firstDayOfWeek <= calendar.StartDate)
{ // two pieces, a first week with the day substracted and the rest.
var subtracted = new Calendar()
{
StartDate = calendar.StartDate,
EndDate = lastDayOfWeek
};
subtracted.CopyWeekPatternFrom(calendar);
subtracted[day.DayOfWeek] = false;
var rest = new Calendar()
{
StartDate = lastDayOfWeek.AddDays(1),
EndDate = calendar.EndDate
};
rest.CopyWeekPatternFrom(calendar);
return(new Calendar[] { subtracted, rest });
}
else if (lastDayOfWeek >= calendar.EndDate)
{ // two pieces, a last week with the day substracted and the rest.
var rest = new Calendar()
{
StartDate = calendar.StartDate,
EndDate = firstDayOfWeek.AddDays(-1)
};
rest.CopyWeekPatternFrom(calendar);
var subtracted = new Calendar()
{
StartDate = firstDayOfWeek,
EndDate = calendar.EndDate
};
subtracted.CopyWeekPatternFrom(calendar);
subtracted[day.DayOfWeek] = false;
return(new Calendar[] { rest, subtracted });
}
else
{ // three pieces, a first period, a week with the day subtracted and a last period.
var rest1 = new Calendar()
{
StartDate = calendar.StartDate,
EndDate = firstDayOfWeek.AddDays(-1)
};
rest1.CopyWeekPatternFrom(calendar);
var subtracted = new Calendar()
{
StartDate = firstDayOfWeek,
EndDate = lastDayOfWeek
};
subtracted.CopyWeekPatternFrom(calendar);
subtracted[day.DayOfWeek] = false;
var rest2 = new Calendar()
{
StartDate = lastDayOfWeek.AddDays(1),
EndDate = calendar.EndDate
};
rest2.CopyWeekPatternFrom(calendar);
return(new Calendar[] { rest1, subtracted, rest2 });
}
}