using System;
using System.Collections.Generic;
using System.Text;
using System.Resources;
using System.IO;

namespace Genus.Core.Utils {

/*
Calendar is an abstract class.  Calendar is designed as a singleton pattern.
Classes that extend Calendar must define the IsHoliday(Date) method.  They should also define a
private constructor and a single static readonly instance variable "c".

Examples of holidays:
	-Canadian holidays vs. US holidays vs. World holidays
	-Genus company holidays
	-Days the TSX or NASDAQ markets are closed
	-Banking holidays

RBCCalendar (implemented)
GenusCalendar (implemented)
USACalendar (not implemented)
CanadaCalendar (not implemented)
TSXCalendar (not implemented)
UnitraxCalendar (not implemented) -- could be used to determine to download TA files or not
*/

public abstract class Calendar {

	public abstract bool IsHoliday(DateTime date);

	/*
	By default, Saturday and Sunday are never considered working days.
	If the date is a holiday then it's not a working day.
	If date is a Monday then it is a holiday if Saturday or Sunday were holidays.
	If date is a Tuesday then it is a holiday if 2 days out of Sat, Sun, Mon are holidays.
	You could continue with this logic (if date is a Wednesday and 3 out of 4 days are holidays ...)
	but that never actually happens.
	*/
	public virtual bool IsWorkingDay(DateTime date) {
		if (date.DayOfWeek == DayOfWeek.Saturday) return false;
		if (date.DayOfWeek == DayOfWeek.Sunday) return false;
		if (IsHoliday(date)) return false;
		if (date.DayOfWeek == DayOfWeek.Monday) {
			// if Saturday or Sunday is a holiday, then Monday is not a working day
			if (IsHoliday(date.AddDays(-1))) return false;
			if (IsHoliday(date.AddDays(-2))) return false;
		}
		else if (date.DayOfWeek == DayOfWeek.Tuesday) {
			bool isSatHoliday = IsHoliday(date.AddDays(-3));
			bool isSunHoliday = IsHoliday(date.AddDays(-2));
			bool isMonHoliday = IsHoliday(date.AddDays(-1));
			if (isSatHoliday && isSunHoliday) return false; // e.g. Xmas on Saturday
			if (isSatHoliday && isMonHoliday) return false; // are any holidays 1 day apart?
			if (isSunHoliday && isMonHoliday) return false; // e.g. Xmas on Sunday
		}
		return true;
	}

	public virtual bool IsFirstBusinessDayOfQuarter(DateTime date)
	{
		int month = date.Month;
		if ( month == 1 || month == 4 || month == 7 || month == 10 )
		{
			DateTime d = new DateTime(date.Year, date.Month, 1);
			while (!IsWorkingDay(d))
				d = d.AddDays(1);
			return date.Day == d.Day;
		}

		return false;
	}

	public virtual bool IsLastBusinessDayOfQuarter(DateTime date)
	{
		int month = date.Month;
		if (month == 4 || month == 6 || month == 9 || month == 12)
		{
			DateTime d = new DateTime(date.Year, date.Month, 1);
			d = d.AddMonths(1).AddDays(-1);
			while (!IsWorkingDay(d))
				d = d.AddDays(-1);
			return date.Day == d.Day;
		}

		return false;
	}

	public virtual bool IsFirstBusinessDayOfYear(DateTime date)
	{
		DateTime d = new DateTime(date.Year, 1, 1);
		while (!IsWorkingDay(d))
			d = d.AddDays(1);
		return d == date;
	}

	public virtual bool IsLastBusinessDayOfYear(DateTime date)
	{
		DateTime d = new DateTime(date.Year, 12, DateTime.DaysInMonth(date.Year, 12));
		while (!IsWorkingDay(d))
			d = d.AddDays(-1);
		return d == date;
	}

	public virtual bool IsFirstBusinessDayOfSemiAnnual(DateTime date)
	{
		if ( date.Month == 1 || date.Month == 7 )
		{
			DateTime d = new DateTime(date.Year, date.Month, 1);
			while (!IsWorkingDay(d))
				d = d.AddDays(1);
			return d == date;
		}
		return false;
	}

	public virtual bool IsLastBusinessDayOfSemiAnnual(DateTime date)
	{
		if (date.Month == 6 || date.Month == 12)
		{
			DateTime d = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
			while (!IsWorkingDay(d))
				d = d.AddDays(-1);
			return d == date;
		}
		return false;
	}

	public virtual bool IsFirstBusinessDayOfMonth(DateTime date) {
		DateTime d = new DateTime(date.Year, date.Month, 1);
		while (!IsWorkingDay(d))
			d = d.AddDays(1);
		return date.Day == d.Day;
	}

	public virtual bool IsLastBusinessDayOfMonth(DateTime date) {
		DateTime d = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
		if (!IsWorkingDay(d))
			d = PreviousBusinessDay(d);
		return d.Day == date.Day;
	}

	public virtual bool IsFirstBusinessDayOfWeek(DateTime date) {
		date = date.Date;
		if (!IsWorkingDay(date)) return false;
		DateTime pbd = PreviousBusinessDay(date);
		return pbd.DayOfWeek > date.DayOfWeek;
	}

	public virtual bool IsLastBusinessDayOfWeek(DateTime date) {
		date = date.Date;
		if (!IsWorkingDay(date)) return false;
		DateTime nbd = NextBusinessDay(date);
		return nbd.DayOfWeek < date.DayOfWeek;
	}

	public virtual DateTime PreviousBusinessDay(DateTime date) {
		DateTime d = date.AddDays(-1);
		while (!IsWorkingDay(d))
			d = d.AddDays(-1);
		return d;
	}

	public virtual DateTime NextBusinessDay(DateTime date) {
		DateTime d = date.AddDays(1);
		while (!IsWorkingDay(d))
			d = d.AddDays(1);
		return d;
	}

	//------------------------------------------------------------------------------------------------------

	public static bool IsNewYears(DateTime date) {
		return date.Month == 1 && date.Day == 1;
	}

	private static void getEasterMD(int y, out int easterMonth, out int easterDay) {
		int a=y%19;
		int b=y/100;
		int c=y%100;
		int d=b/4;
		int e=b%4;
		int f=(b+8)/25;
		int g=(b-f+1)/3;
		int h=(19*a+b-d-g+15)%30;
		int i=c/4;
		int k=c%4;
		int l=(32+2*e+2*i-h-k)%7;
		int m=(a+11*h+22*l)/451;
		easterMonth=(h+l-7*m+114)/31;
		int p=(h+l-7*m+114)%31;
		easterDay=p+1;
	}

	// 3rd Monday in February
	public static bool IsFamilyDayOntario(DateTime date) {
		// Family Day in Ontario wasn't observed until 2008.
		if (date.Year < 2008) return false;
		if (date.Month != 2) return false;
		if (date.DayOfWeek != DayOfWeek.Monday) return false;
		int numMondays = 0;
		while (date.Month == 2) {
			if (date.DayOfWeek == DayOfWeek.Monday)
				numMondays++;
			date = date.AddDays(-1);
		}
		return numMondays == 3;
	}

	// Easter always falls on Sunday, generally it's not considered a holiday because
	// Calendars can use the IsEasterMonday method instead.  Don't define Easter and
	// EasterMonday has holidays because then Tuesday will not be a working day.
	public static bool IsEaster(DateTime date) {
		int easterMonth = 0;
		int easterDay = 0;
		getEasterMD(date.Year, out easterMonth, out easterDay);
		return date.Month == easterMonth && date.Day == easterDay;
	}

	public static bool IsGoodFriday(DateTime date) {
		int easterMonth = 0;
		int easterDay = 0;
		getEasterMD(date.Year, out easterMonth, out easterDay);
		int goodFriday=easterDay-2;
		if (goodFriday < 1) {
			goodFriday+=31;
			easterMonth--;
		}
		return date.Month == easterMonth && date.Day == goodFriday;
	}

	public static bool IsEasterMonday(DateTime date) {
		int easterMonth = 0;
		int easterDay = 0;
		getEasterMD(date.Year, out easterMonth, out easterDay);
		int easterMonday = easterDay + 1;
		if (easterMonday > 31) {
			easterMonday = 1;
			easterMonth = 4;
		}
		return date.Month == easterMonth && date.Day == easterMonday;
	}

	// celebrated on the last Monday before or on May 24 
	public static bool IsVictoriaDay(DateTime date) {
		if (date.Month != 5) return false;
		DateTime d = new DateTime(date.Year, 5, 24);
		while (d.DayOfWeek != DayOfWeek.Monday)
			d = d.AddDays(-1);
		return date.Day == d.Day;
	}

	public static bool IsCanadaDay(DateTime date) {
		return date.Month == 7 && date.Day == 1;
	}

	// first Monday in August -- Canadian Holiday
	public static bool IsCivicDay(DateTime date) { // aka B.C. Day
		if (date.Month != 8) return false;
		DateTime d = new DateTime(date.Year, 8, 1);
		while (d.DayOfWeek != DayOfWeek.Monday)
			d = d.AddDays(1);
		return date.Day == d.Day;
	}

	// first Monday in September -- US Holiday
	public static bool IsLaborDay(DateTime date) {
		if (date.Month != 9) return false;
		DateTime d = new DateTime(date.Year, 9, 1);
		while (d.DayOfWeek != DayOfWeek.Monday)
			d = d.AddDays(1);
		return date.Day == d.Day;
	}

	// fourth Thursday in November
	public static bool IsThanksGivingUSA(DateTime date) {
		if (date.Month != 11) return false;
		DateTime d = new DateTime(date.Year, 11, 1);
		int x = 0;
		while (true) {
			if (d.DayOfWeek == DayOfWeek.Thursday) x++;
			if (x == 4) break;
			d = d.AddDays(1);
		}
		return date.Day == d.Day;
	}

	// Second Monday in October
	public static bool IsThanksGivingCanada(DateTime date) {
		if (date.Month != 10) return false;
		DateTime d = new DateTime(date.Year, 10, 1);
		int x = 0;
		while (true) {
			if (d.DayOfWeek == DayOfWeek.Monday) x++;
			if (x == 2) break;
			d = d.AddDays(1);
		}
		return date.Day == d.Day;
	}

	public static bool IsRemembranceDay(DateTime date) {
		return date.Month == 11 && date.Day == 11;
	}

	public static bool IsChristmas(DateTime date) {
		return date.Month == 12 && date.Day == 25;
	}

	public static bool IsBoxingDay(DateTime date) {
		return date.Month == 12 && date.Day == 26;
	}

	#region US Holidays

	// 3rd monday in Jan
	public static bool IsMartinLutherKingDay(DateTime date) {
		// MLK Day was closed for 1 minute of silence at noon since 1986, and closed all day beginning in 1998.
		if (date.Year < 1998) return false;
		if (date.Month != 1) return false;
		DateTime d = new DateTime(date.Year, 1, 1);
		int x = 0;
		while (true) {
			if (d.DayOfWeek == DayOfWeek.Monday) x++;
			if (x == 3) break;
			d = d.AddDays(1);
		}
		return date.Day == d.Day;
	}

	// Feb 15
	// Observed is the first monday on or after Feb 15
	public static bool IsPresidentsDay(DateTime date) {
		if (date.Month != 2) return false;
		DateTime d = new DateTime(date.Year, 2, 15);
		while (d.DayOfWeek != DayOfWeek.Monday)
			d = d.AddDays(1);
		return date.Day == d.Day;
	}

	// last Monday in May
	public static bool IsMemorialDay(DateTime date) {
		if (date.Month != 5) return false;
		DateTime d = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
		while (true) {
			if (d.DayOfWeek == DayOfWeek.Monday) break;
			d = d.AddDays(-1);
		}
		return date.Day == d.Day;
	}

	// July 4
	public static bool IsIndependenceDay(DateTime date) {
		return date.Month == 7 && date.Day == 4;
	}

	// Nov 11
	public static bool IsVeteransDay(DateTime date) {
		return date.Month == 11 && date.Day == 11;
	}

	public static String getHolidayName(DateTime date) {
		if (IsBoxingDay(date)) return "BoxingDay";
		if (IsCanadaDay(date)) return "CanadaDay";
		if (IsChristmas(date)) return "Christmas";
		if (IsCivicDay(date)) return "CivicDay";
		if (IsEaster(date)) return "Easter";
		if (IsEasterMonday(date)) return "EasterMonday";
		if (IsFamilyDayOntario(date)) return "FamilyDayOntario";
		if (IsGoodFriday(date)) return "GoodFriday";
		if (IsIndependenceDay(date)) return "IndependenceDay";
		if (IsLaborDay(date)) return "LaborDay";
		if (IsMartinLutherKingDay(date)) return "MartinLurtherKingDay";
		if (IsMemorialDay(date)) return "MemorialDay";
		if (IsNewYears(date)) return "NewYears";
		if (IsPresidentsDay(date)) return "PresidentsDay";
		if (IsRemembranceDay(date)) return "RemembranceDay";
		if (IsThanksGivingCanada(date)) return "ThanksGivingCanada";
		if (IsThanksGivingUSA(date)) return "ThanksGivingUSA";
		if (IsVeteransDay(date)) return "VeteransDay";
		if (IsVictoriaDay(date)) return "VictoriaDay";
		return null;
	}

	#endregion
	

	public static bool IsFirst60Days(DateTime date) {
		// bit of optimization.  Jan & Feb are always in first 60 days
		// Anything after March 3 is never in first 60 days.
		if (date.Month == 1 || date.Month == 2)
			return true;
		else if (date.Month > 3 || date.Day > 3) return false;

		// generally, March 1st is the 60th day.
		// but in a leap year Feb 29th is the 60th day.
		// If the 60th day falls on Sat or Sun then the
		// next Monday is considered the 60th day

		DateTime d = new DateTime(date.Year, 1, 1);
		d = d.AddDays(59); // add 59 days, not 60!
		if (d.DayOfWeek == DayOfWeek.Saturday)
			d = d.AddDays(2);
		else if (d.DayOfWeek == DayOfWeek.Sunday)
			d = d.AddDays(1);
		return date.Date <= d;
	}
}
}