EPPlus/FormulaParsing/Excel/Functions/DateTime/Workdays/HolidayWeekdaysFactory.cs

using System;
using System.Collections.Generic;

namespace OfficeOpenXml.FormulaParsing.Excel.Functions.DateTime.Workdays;

public class HolidayWeekdaysFactory {
  private readonly DayOfWeek[] _dayOfWeekArray = {
    DayOfWeek.Monday,
    DayOfWeek.Tuesday,
    DayOfWeek.Wednesday,
    DayOfWeek.Thursday,
    DayOfWeek.Friday,
    DayOfWeek.Saturday,
    DayOfWeek.Sunday,
  };

  public HolidayWeekdays Create(string weekdays) {
    if (string.IsNullOrEmpty(weekdays) || weekdays.Length != 7) {
      throw new ArgumentException("Illegal weekday string", nameof(Weekday));
    }

    var retVal = new List<DayOfWeek>();
    var arr = weekdays.ToCharArray();
    for (var i = 0; i < arr.Length; i++) {
      var ch = arr[i];
      if (ch == '1') {
        retVal.Add(_dayOfWeekArray[i]);
      }
    }
    return new(retVal.ToArray());
  }

  public HolidayWeekdays Create(int code) {
    switch (code) {
      case 1:
        return new(DayOfWeek.Saturday, DayOfWeek.Sunday);
      case 2:
        return new(DayOfWeek.Sunday, DayOfWeek.Monday);
      case 3:
        return new(DayOfWeek.Monday, DayOfWeek.Tuesday);
      case 4:
        return new(DayOfWeek.Tuesday, DayOfWeek.Wednesday);
      case 5:
        return new(DayOfWeek.Wednesday, DayOfWeek.Thursday);
      case 6:
        return new(DayOfWeek.Thursday, DayOfWeek.Friday);
      case 7:
        return new(DayOfWeek.Friday, DayOfWeek.Saturday);
      case 11:
        return new(DayOfWeek.Sunday);
      case 12:
        return new(DayOfWeek.Monday);
      case 13:
        return new(DayOfWeek.Tuesday);
      case 14:
        return new(DayOfWeek.Wednesday);
      case 15:
        return new(DayOfWeek.Thursday);
      case 16:
        return new(DayOfWeek.Friday);
      case 17:
        return new(DayOfWeek.Saturday);
      default:
        throw new ArgumentException("Invalid code supplied to HolidayWeekdaysFactory: " + code);
    }
  }
}