/// <summary>
/// Creates a relative date expression with symbol scope, context, script refernce set.
/// The date expression can handle relative dates: 3rd monday of january
/// </summary>
/// <param name="name"></param>
/// <param name="token"></param>
/// <returns></returns>
public static Expr DateRelative(string relativeDay, int dayOfWeek, int month, TokenData token)
{
var exp = new DateRelativeExpr();
exp.RelativeDay = relativeDay;
exp.Month = month;
exp.DayOfTheWeek = dayOfWeek;
SetupContext(exp, token);
return(exp);
}
/// <summary>
/// Visit the relative date expression.
/// </summary>
/// <param name="expr"></param>
/// <returns></returns>
public object VisitDateRelative(DateRelativeExpr expr)
{
return(null);
}
public object VisitDateRelative(DateRelativeExpr expr)
{
var year = DateTime.Now.Year;
var month = expr.Month;
var dayofWeek = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), expr.DayOfTheWeek.ToString());
var date = new DateTime(year, month, 1);
var DaysInWeek = 7;
// move to holiday day of week
var dayInc = 0;
while (date.DayOfWeek != dayofWeek && dayInc <= DaysInWeek)
{
date = date.AddDays(1);
dayInc++;
}
var relDay = expr.RelativeDay.ToLower();
// Case 1: "last" <day> of <month>
if (relDay == "last")
{
// 1. Add 2 weeks at least
date = date.AddDays(14);
var i = 0;
var totalDaysInMonth = _daysInMonth[date.Month];
while (i < 2)
{
// 2. feb check
if (date.Month == 2 && (date.Day + 7) <= 28)
{
date = date.AddDays(7);
}
else if (date.Day + 7 <= totalDaysInMonth)
{
date = date.AddDays(7);
}
i++;
}
}
// Case 2:
else
{
var weekCount = 0;
if (relDay == "first")
{
weekCount = 1;
}
else if (relDay == "second")
{
weekCount = 2;
}
else if (relDay == "third")
{
weekCount = 3;
}
else if (relDay == "fourth")
{
weekCount = 4;
}
// Case 2a: "first|second|third|fourth" of month
if (weekCount > 0)
{
date = date.AddDays((weekCount - 1) * DaysInWeek);
}
// Case 2b: ( 1st | 2nd | 3rd| 4th ) of month
else
{
weekCount = Convert.ToInt32(expr.RelativeDay);
date = date.AddDays((weekCount - 1) * DaysInWeek);
}
}
return(new LDate(date));
}
