using System;
using System.Collections.Generic;
using System.Text;
namespace PMSLib.Utils {
public sealed class SpecialDateTime {
private int _year, _month, _day;
private int _week;
private int _maxDays;
public SpecialDateTime(int year, int month, int day) {
_year = year;
_month = month;
_day = day;
_maxDays = DateTime.DaysInMonth(year, month);
}
public SpecialDateTime(int year, int month) {
_year = year;
_month = month;
_day = 1;
_maxDays = DateTime.DaysInMonth(year, month);
}
public SpecialDateTime() { }
public int Removal {
get {
int removal = 7 - (int)(new DateTime(_year, _month, 1).DayOfWeek);
return removal == 7 ? 0 : removal;
}
}
public int Markup {
get {
return (6 - (int)(new DateTime(_year, _month, _maxDays).DayOfWeek));
}
}
public int WeeksInMonth {
get {
return (_maxDays + Markup - Removal) / 7;
}
}
public int DaysInMonth {
get { return (EndDateOfMonth - StartDateOfMonth).Days + 1; }
}
public DateTime StartDateOfMonth {
get { return new DateTime(_year, _month, 1).AddDays(Removal); }
}
public DateTime EndDateOfMonth {
get { return new DateTime(_year, _month, _maxDays).AddDays(Markup); }
}
public void GetWeekInMonthBy(int year, int month, int day, out int realMonth, out int week) {
int removal = 7 - (int)(new DateTime(year, month, 1).DayOfWeek);
removal = removal == 7 ? 0 : removal;
TimeSpan ts = new DateTime(year, month, day) - new DateTime(year, month, 1).AddDays(removal);
if(ts.Days < 0) {
realMonth = month - 1;
removal = 7 - (int)(new DateTime(year, realMonth, 1).DayOfWeek);
removal = removal == 7 ? 0 : removal;
TimeSpan ts1 = new DateTime(year, month, day) - new DateTime(year, realMonth, 1).AddDays(removal);
week = (int)Math.Ceiling(ts1.Days == 0 ? 1 : (ts1.Days) * 1.0 / 7);
} else {
realMonth = month;
week = (int)Math.Ceiling(ts.Days == 0 ? 1 : ts.Days * 1.0 / 7);
if(ts.Days != 0 && ts.Days % 7 == 0) {
week = week + 1;
}
}
}
public DateTime GetDateBy(int year, int month, int weekInMonth, DayOfWeek dayOfWeek) {
if(month > 12) {
year += month / 12;
month = month % 12;
}
int removal = 7 - (int)(new DateTime(year, month, 1).DayOfWeek);
removal = removal == 7 ? 0 : removal;
DateTime startDate = new DateTime(year, month, 1).AddDays(removal);
return startDate.AddDays((weekInMonth - 1) * 7 + (int)dayOfWeek);
}
public void GetDateRangeInWeek(int year, int month, int week, out DateTime startDate, out DateTime endDate) {
startDate = (new DateTime(year, month, 1).AddDays(Removal).AddDays((week - 1) * 7));
endDate = (new DateTime(year, month, 1).AddDays(Removal).AddDays((week - 1) * 7 + 6));
}
public IList<DateTime> GetDatesBy(int minWeekInMonth, DayOfWeek dow, int interval) {
IList<DateTime> dates = new List<DateTime>();
while(GetDateBy(_year, _month, minWeekInMonth, dow) <= EndDateOfMonth) {
dates.Add(GetDateBy(_year, _month, minWeekInMonth, dow));
minWeekInMonth += interval;
}
return dates;
}
public IList<DateTime> GetDatesBy(DateTime date, int interval, string unit, int realMonth) {
IList<DateTime> dates = new List<DateTime>();
SpecialDateTime sdt = new SpecialDateTime(date.Year, realMonth);
if(unit.Equals("W")) {
do {
DateTime d = date.AddDays(7 * interval);
if(sdt.StartDateOfMonth > d || d > sdt.EndDateOfMonth) break;
dates.Add(d);
date = d;
} while(sdt.StartDateOfMonth <= date && date <= sdt.EndDateOfMonth);
} else {
int week, month;
sdt.GetWeekInMonthBy(date.Year, date.Month, date.Day, out month, out week);
DateTime d = sdt.GetDateBy(date.Year, month + interval, week, date.DayOfWeek);
if(realMonth == month + interval) {
dates.Add(d);
}
}
return dates;
}
}
}