dojo.provide("dojo.date.supplemental");

dojo.date.getFirstDayOfWeek = function(/*String?*/locale){
// summary: Returns a zero-based index for first day of the week
// description:
//		Returns a zero-based index for first day of the week, as used by the local (Gregorian) calendar.
//		e.g. Sunday (returns 0), or Monday (returns 1)

	// from http://www.unicode.org/cldr/data/common/supplemental/supplementalData.xml:supplementalData/weekData/firstDay
	var firstDay = {/*default is 1=Monday*/
		mv:5,
		ae:6,af:6,bh:6,dj:6,dz:6,eg:6,er:6,et:6,iq:6,ir:6,jo:6,ke:6,kw:6,lb:6,ly:6,ma:6,om:6,qa:6,sa:6,
		sd:6,so:6,tn:6,ye:6,
		as:0,au:0,az:0,bw:0,ca:0,cn:0,fo:0,ge:0,gl:0,gu:0,hk:0,ie:0,il:0,is:0,jm:0,jp:0,kg:0,kr:0,la:0,
		mh:0,mo:0,mp:0,mt:0,nz:0,ph:0,pk:0,sg:0,th:0,tt:0,tw:0,um:0,us:0,uz:0,vi:0,za:0,zw:0,
		et:0,mw:0,ng:0,tj:0,
		gb:0,
		sy:4
	};

	locale = dojo.hostenv.normalizeLocale(locale);
	var country = locale.split("-")[1];
	var dow = firstDay[country];
	return (typeof dow == 'undefined') ? 1 : dow; /*Number*/
};

dojo.date.getWeekend = function(/*String?*/locale){
// summary: Returns a hash containing the start and end days of the weekend
// description:
//		Returns a hash containing the start and end days of the weekend according to local custom using locale,
//		or by default in the user's locale.
//		e.g. {start:6, end:0}

	// from http://www.unicode.org/cldr/data/common/supplemental/supplementalData.xml:supplementalData/weekData/weekend{Start,End}
	var weekendStart = {/*default is 6=Saturday*/
		eg:5,il:5,sy:5,
		'in':0,
		ae:4,bh:4,dz:4,iq:4,jo:4,kw:4,lb:4,ly:4,ma:4,om:4,qa:4,sa:4,sd:4,tn:4,ye:4		
	};

	var weekendEnd = {/*default is 0=Sunday*/
		ae:5,bh:5,dz:5,iq:5,jo:5,kw:5,lb:5,ly:5,ma:5,om:5,qa:5,sa:5,sd:5,tn:5,ye:5,af:5,ir:5,
		eg:6,il:6,sy:6
	};

	locale = dojo.hostenv.normalizeLocale(locale);
	var country = locale.split("-")[1];
	var start = weekendStart[country];
	var end = weekendEnd[country];
	if(typeof start == 'undefined'){start=6;}
	if(typeof end == 'undefined'){end=0;}
	return {start:start, end:end}; /*Object {start,end}*/
};

dojo.date.isWeekend = function(/*Date?*/dateObj, /*String?*/locale){
// summary:
//	Determines if the date falls on a weekend, according to local custom.

	var weekend = dojo.date.getWeekend(locale);
	var day = (dateObj || new Date()).getDay();
	if(weekend.end<weekend.start){
		weekend.end+=7;
		if(day<weekend.start){ day+=7; }
	}
	return day >= weekend.start && day <= weekend.end; // Boolean
};
