using System;
using System.Collections.Generic;
using System.Collections;
using System.Text;
using System.ComponentModel;

namespace Genus.Core.Utils {
/*
GDate allows a date to be specified in a generic fashion.  A string
representation is supplied to the constuctor and that string is parsed.
Out of that string come two types of objects, GDAlign and GDAdjust.
A GDAlign object is used to align a date to the first or last day of
a period.  A GDAdjust object is used to add or subtract a specified
number of days, business days, weeks, months, quarters or years from a
date.

As many GDAjust and GDAlign tokens can be in the string as required to
achieve the desired date behaviour.  The tokens are applied in the order
they appear in the string.

You can align to the first day, first business day, last day or last
business day of a week, month, quarter or year.  See the GDAlign enum for
all the options.

An adjustment is an adding or subtracting of days, business days, weeks,
months, quarters or years to a date.
Exmaples:
	tomorrow = d+1
	previous business day = bd-1
	next year = y+1
	prev year = y-1
	prev quarter = q-1
	five weeks ago = w-5

Here are some examples of GDate strings:
	bd-1         : previous business day
	m-1,mld      : last day of last month
	m-1,y-1,mld  : last day of last month one year ago
	y-1,mfd      : one year ago, first day of this month
	q-1,qld      : last day of last quarter
	y-1,qfd      : first day of this quarter one year ago


Note: Axys has their own version of generic dates, which does not allow
adding or substracting arbitrary amounts, and does not allow adjusting more
than one period.  As such, Axys generic dates don't cover all business needs.

*/
public class GDate {

	public ArrayList list = new ArrayList();

	public GDate(String s) {
		s = s.ToLower();
		String[] arr = s.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
		List<GDAlign> alignList = GEnum<GDAlign>.getEnums();
		Hashtable alignHT = new Hashtable(StringComparer.InvariantCultureIgnoreCase);
		foreach (GDAlign a in alignList)
			alignHT["" + a] = a;

		for (int i = 0; i < arr.Length; i++) {
			String x = arr[i];
			Object o = alignHT[x];
			if (o != null)
				list.Add((GDAlign) o);
			else
				list.Add(new GDAdjust(x));
		}
	}

	public DateTime getDate(DateTime date, Calendar cal) {
		for (int i = 0; i < list.Count; i++) {
			if (list[i] is GDAlign)
				date = align(date, (GDAlign) list[i], cal);
			else
				date = adjust(date, (GDAdjust) list[i], cal);
		}

		return date;
	}

	public static DateTime adjust(DateTime date, GDAdjust adjust, Calendar cal) {
		if (adjust.period == GDPeriod.d)
			date = date.AddDays(adjust.amount);
		else if (adjust.period == GDPeriod.bd) {
			if (adjust.amount > 0) {
				for (int i = 0; i < adjust.amount; i++)
					date = cal.NextBusinessDay(date);
			}
			else if (adjust.amount < 0) {
				for (int i = 0; i > adjust.amount; i--)
					date = cal.PreviousBusinessDay(date);
			}
		}
		else if (adjust.period == GDPeriod.w)
			date = date.AddDays(7 * adjust.amount);
		else if (adjust.period == GDPeriod.m)
			date = date.AddMonths(adjust.amount);
		else if (adjust.period == GDPeriod.q)
			date = date.AddMonths(3 * adjust.amount);
		else if (adjust.period == GDPeriod.y)
			date = date.AddYears(adjust.amount);
		return date;
	}

	public static DateTime align(DateTime date, GDAlign align, Calendar cal) {
		if (align == GDAlign.wfbd) {
			while (date.DayOfWeek != DayOfWeek.Sunday)
				date = date.AddDays(-1);
			date = cal.NextBusinessDay(date);
		}
		else if (align == GDAlign.wfd) {
			while (date.DayOfWeek != DayOfWeek.Sunday)
				date = date.AddDays(-1);
		}
		else if (align == GDAlign.wlbd) {
			while (date.DayOfWeek != DayOfWeek.Saturday)
				date = date.AddDays(1);
			date = cal.PreviousBusinessDay(date);
		}
		else if (align == GDAlign.wld) {
			while (date.DayOfWeek != DayOfWeek.Saturday)
				date = date.AddDays(1);
		}
		else if (align == GDAlign.mfbd) {
			date = new DateTime(date.Year, date.Month, 1);
			if (!cal.IsWorkingDay(date))
				date = cal.NextBusinessDay(date);
		}
		else if (align == GDAlign.mfd) {
			date = new DateTime(date.Year, date.Month, 1);
		}
		else if (align == GDAlign.mlbd) {
			date = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
			if (!cal.IsWorkingDay(date))
				date = cal.PreviousBusinessDay(date);
		}
		else if (align == GDAlign.mld) {
			date = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
		}
		else if (align == GDAlign.qfbd) { // 1, 4, 7, 10
			date = new DateTime(date.Year, date.Month - (date.Month - 1) % 3, 1);
			if (!cal.IsWorkingDay(date))
				date = cal.NextBusinessDay(date);
		}
		else if (align == GDAlign.qfd) {
			date = new DateTime(date.Year, date.Month - (date.Month - 1) % 3, 1);
		}
		else if (align == GDAlign.qlbd) { // 3, 6, 9, 12
			int m = 2 + date.Month - (date.Month - 1) % 3;
			date = new DateTime(date.Year, m, DateTime.DaysInMonth(date.Year, m));
			if (!cal.IsWorkingDay(date))
				date = cal.PreviousBusinessDay(date);
			
		}
		else if (align == GDAlign.qld) {
			int m = 2 + date.Month - (date.Month - 1) % 3;
			date = new DateTime(date.Year, m, DateTime.DaysInMonth(date.Year, m));
		}
		else if (align == GDAlign.yfbd) {
			date = new DateTime(date.Year, 1, 1);
			if (!cal.IsWorkingDay(date))
				date = cal.NextBusinessDay(date);
		}
		else if (align == GDAlign.yfd) {
			date = new DateTime(date.Year, 1, 1);
		}
		else if (align == GDAlign.ylbd) {
			date = new DateTime(date.Year, 12, 31);
			if (!cal.IsWorkingDay(date))
				date = cal.PreviousBusinessDay(date);
		}
		else if (align == GDAlign.yld) {
			date = new DateTime(date.Year, 12, 31);
		}
		else if (align == GDAlign.mfMon)
			date = AlignMonthFirstDOW(date, DayOfWeek.Monday);
		else if (align == GDAlign.mfTue)
			date = AlignMonthFirstDOW(date, DayOfWeek.Tuesday);
		else if (align == GDAlign.mfWed)
			date = AlignMonthFirstDOW(date, DayOfWeek.Wednesday);
		else if (align == GDAlign.mfThu)
			date = AlignMonthFirstDOW(date, DayOfWeek.Thursday);
		else if (align == GDAlign.mfFri)
			date = AlignMonthFirstDOW(date, DayOfWeek.Friday);
		else if (align == GDAlign.mfSat)
			date = AlignMonthFirstDOW(date, DayOfWeek.Saturday);
		else if (align == GDAlign.mfSun)
			date = AlignMonthFirstDOW(date, DayOfWeek.Sunday);

		else if (align == GDAlign.mlMon)
			date = AlignMonthLastDOW(date, DayOfWeek.Monday);
		else if (align == GDAlign.mlTue)
			date = AlignMonthLastDOW(date, DayOfWeek.Tuesday);
		else if (align == GDAlign.mlWed)
			date = AlignMonthLastDOW(date, DayOfWeek.Wednesday);
		else if (align == GDAlign.mlThu)
			date = AlignMonthLastDOW(date, DayOfWeek.Thursday);
		else if (align == GDAlign.mlFri)
			date = AlignMonthLastDOW(date, DayOfWeek.Friday);
		else if (align == GDAlign.mlSat)
			date = AlignMonthLastDOW(date, DayOfWeek.Saturday);
		else if (align == GDAlign.mlSun)
			date = AlignMonthLastDOW(date, DayOfWeek.Sunday);


		return date;
	}

	private static DateTime AlignMonthFirstDOW(DateTime date, DayOfWeek dow) {
		date = new DateTime(date.Year, date.Month, 1);
		while (date.DayOfWeek != dow)
			date = date.AddDays(1);
		return date;
	}

	private static DateTime AlignMonthLastDOW(DateTime date, DayOfWeek dow) {
		date = new DateTime(date.Year, date.Month, DateTime.DaysInMonth(date.Year, date.Month));
		while (date.DayOfWeek != dow)
			date = date.AddDays(-1);
		return date;
	}
}

/*
	d = Day
	bd = Business Day
	w = week
	m = month
	q = quarter
	y = year
*/
public enum GDPeriod {

	[Description("Day")]
	d = 0,

	[Description("Business Day")]
	bd = 1,

	[Description("Week")]
	w = 2,

	[Description("Month")]
	m = 3,

	[Description("Quarter")]
	q = 4,

	[Description("Year")]
	y = 5

}

public class GDAdjust {

	public GDPeriod period = GDPeriod.d;
	public int amount = 0;

	/*
	The string has 3 parts:  period, operator and amount
	period can be one of the GDPeriod enums

	operator can be one of:
		+ (plus)
		- (minus)

	amount must be an integer value

	Example:  bd+5
	*/
	public GDAdjust(String s) {
		// could support a full on expression tree but that would be overkill
		// also, certain operations don't make sense, e.g. weeks * 5
		s = s.ToLower();
		s = s.Replace("+", " + ").Replace("-", " - ");
		String[] arr = s.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
		if (arr.Length != 3)
			throw new Exception("Invalid GDate adjustment token: " + s);

		int factor = 0;
		if (arr[1] == "+")
			factor = 1;
		else if (arr[1] == "-")
			factor = -1;
		else
			throw new Exception("Invalid GDate adjustment operator: " + arr[1]);

		if (!int.TryParse(arr[2], out amount))
			throw new Exception("Invaild GDate adjustment amount: " + arr[2]);

		amount = amount * factor;

		period = GEnum<GDPeriod>.getEnum(arr[0]);
	}
}


/*
wfd = first day of week (Sunday)
wfbd = first business day of week (typically Monday but depends on holidays)
wld = last day of week (Saturday)
wlbd = last business day of week (typically Friday but depends on holidays)
mfd = first day of month (day = 1)
mld = last day of month (day = Last Day In Month)
mfbd = first business day of month
mlbd = last business day of month
qfd = first day of quarter (Jan 1, Apr 1, Jul 1, Oct 1)
qld = last day of quarter (Mar 31, Jun 30, Sep 30, Dec 31)
qfbd = first business day of quarter
qlbd = last business day of quarter
yfd = first day of year (Jan 1)
yld = last day of year (Dec 31)
yfbd = first business day of year
ylbd = last business day of year

mfMon = first Monday of month
mfTue = first Tuesday of month
mfWed = first Wednesday of month
mfThu = first Thursday of month
mfFri = first Friday of month
mfSat = first Saturday of month
mfSun = first Sunday of month

mlMon = last Monday of month
mlTue = last Tuesday of month
mlWed = last Wednesday of month
mlThu = last Thursday of month
mlFri = last Friday of month
mlSat = last Saturday of month
mlSun = last Sunday of month

*/
public enum GDAlign {

	none = 0,

	wfbd = 1,
	wfd = 2,
	wlbd = 3,
	wld = 4,

	mfbd = 5,
	mfd = 6,
	mlbd = 7,
	mld = 8,

	qfbd = 9,
	qfd = 10,
	qlbd = 11,
	qld = 12,

	yfbd = 13,
	yfd = 14,
	ylbd = 15,
	yld = 16,

	mfMon = 17,
	mfTue = 18,
	mfWed = 19,
	mfThu = 20,
	mfFri = 21,
	mfSat = 22,
	mfSun = 23,

	mlMon = 24,
	mlTue = 25,
	mlWed = 26,
	mlThu = 27,
	mlFri = 28,
	mlSat = 29,
	mlSun = 30
}







}