Cara mendapatkan 14 hari sebelum tanggal yang diberikan menghindari hari libur

Saya akan menghitung Tanggal menggunakan fungsi seperti di bawah ini (yang saya gunakan)

public static DateTime AddBusinessDays(DateTime date, int days)
 {
    if (days == 0) return date;

   if (date.DayOfWeek == DayOfWeek.Saturday)
   {
    date = date.AddDays(2);
    days -= 1;
  }
  else if (date.DayOfWeek == DayOfWeek.Sunday)
  {
    date = date.AddDays(1);
    days -= 1;
  } 



 date = date.AddDays(days / 5 * 7);
 int extraDays = days % 5;

 if ((int)date.DayOfWeek + extraDays > 5)
 {
    extraDays += 2;
 }

int extraDaysForHolidays =-1;
//Load holidays from DB into list
List<DateTime> dates = GetHolidays();

while(extraDaysForHolidays !=0)
{

 var days =  dates.Where(x => x >= date  && x <= date.AddDays(extraDays)).Count;
 extraDaysForHolidays =days;
 extraDays+=days;  
}


return date.AddDays(extraDays);

}

Belum menguji bagian ast yang melakukan liburan