finding end date from start date with removing a delay

Question

I have a methode like this

public static DateTime Final_Date_Provider(DateTime start, TimeSpan offset)
{    
//code    
}

this method is supposed to caclcule EndDate = start + offset

the problem is :

i want it to do that from 8 am to 5 pm with removing the delay 12 until 12:30

and sundays and holidays.

UPDATE !

public static DateTime Final_Date_Provider(DateTime start, TimeSpan offset)
{       
    const int hoursPerDay = 8;
    const int startHour = 8;

    // Don't start counting hours until start time is during working hours
    if (start.TimeOfDay.TotalHours > startHour + hoursPerDay)
        start = start.Date.AddDays(1).AddHours(startHour);

    if (start.TimeOfDay.TotalHours < startHour)
        start = start.Date.AddHours(startHour);


    if (start.DayOfWeek == DayOfWeek.Saturday)
        start.AddDays(2);
    else if (start.DayOfWeek == DayOfWeek.Sunday)
        start.AddDays(1);

    // Calculate how much working time already passed on the first day
    TimeSpan firstDayOffset =
       start.TimeOfDay.Subtract(TimeSpan.FromHours(startHour));   

    // Calculate number of whole days to add  
    int wholeDays = (int)(offset.Add(firstDayOffset).TotalHours / hoursPerDay);

    // How many hours off the specified offset does this many whole days consume?
    TimeSpan wholeDaysHours = TimeSpan.FromHours(wholeDays * hoursPerDay);

    // Calculate the final time of day based on the number of whole days spanned and the specified offset
    TimeSpan remainder = offset - wholeDaysHours;

    // How far into the week is the starting date?
    int weekOffset = ((int)(start.DayOfWeek + 7) - (int)DayOfWeek.Monday) % 7;

    // How many weekends are spanned?
    int weekends = (int)((wholeDays + weekOffset) / 5);

    // Calculate the final result using all the above calculated values      
    return start.AddDays(wholeDays + weekends * 2).Add(remainder);
}

Answer 1

You can use the CalendarDateAdd class of the Time Period Library for .NET:

// ----------------------------------------------------------------------
public void FinalDateProvider()
{
    DateTime now = new DateTime( 2014, 5, 16, 9, 0, 0 );
    TimeSpan offset = new TimeSpan( 15, 0, 0 );
    Console.WriteLine( "{0} + {1} = {2}", now, offset, CalcFinalDate( now, offset ) );
} // FinalDateProvider

// ----------------------------------------------------------------------
public DateTime? CalcFinalDate( DateTime start, TimeSpan offset )
{
    CalendarDateAdd dateAdd = new CalendarDateAdd();
    dateAdd.AddWorkingWeekDays();
    dateAdd.WorkingHours.Add( new HourRange( 8, 12 ) );
    dateAdd.WorkingHours.Add( new HourRange( new Time( 12, 30 ), new Time( 17 ) ) );
    return dateAdd.Add( start, offset );
} // CalcFinalDate

Answer 2

Try something like:

public static DateTime Final_Date_Provider(DateTime start, TimeSpan offset)
{
    // If DateTime.Now is between 8 am and 5pm
    //  If DateTime.Now is not between 12 and 12:30
    //    DateTime changed = start.Add(offset);

    // If Sunday || Holiday
    //   Do something different

    return changed;
}