/* This file is ripped out of the dojo source code. I don't want to depend on 
 * the whole of dojo, so this has been hacked about a bit.
 *   -NS 2007-08-16 */

var dojo = {date:{stamp:{}}};

// Methods to convert dates to or from a wire (string) format using well-known conventions

dojo.date.stamp.fromISOString = function(/*String*/formattedString, /*Number?*/defaultTime){
	//	summary:
	//		Returns a Date object given a string formatted according to a subset of the ISO-8601 standard.
	//
	//	description:
	//		Accepts a string formatted according to a profile of ISO8601 as defined by
	//		RFC3339 (http://www.ietf.org/rfc/rfc3339.txt), except that partial input is allowed.
	//		Can also process dates as specified by http://www.w3.org/TR/NOTE-datetime
	//		The following combinations are valid:
	// 			* dates only
	//				yyyy
	//				yyyy-MM
	//				yyyy-MM-dd
	// 			* times only, with an optional time zone appended
	//				THH:mm
	//				THH:mm:ss
	//				THH:mm:ss.SSS
	// 			* and "datetimes" which could be any combination of the above
	//		timezones may be specified as Z (for UTC) or +/- followed by a time expression HH:mm
	//		Assumes the local time zone if not specified.  Does not validate.  Improperly formatted
	//		input may return null.  Arguments which are out of bounds will be handled
	// 		by the Date constructor (e.g. January 32nd typically gets resolved to February 1st)
	//
	//	formattedString:
	//		A string such as 2005-06-30T08:05:00-07:00 or 2005-06-30 or T08:05:00
	//
	//	defaultTime:
	//		Used for defaults for fields omitted in the formattedString.
	//		Uses 1970-01-01T00:00:00.0Z by default.

	if(!dojo.date.stamp._isoRegExp){
		dojo.date.stamp._isoRegExp =
//TODO: could be more restrictive and check for 00-59, etc.
			/^(?:(\d{4})(?:-(\d{2})(?:-(\d{2}))?)?)?(?:T(\d{2}):(\d{2})(?::(\d{2})(.\d+)?)?((?:[+-](\d{2}):(\d{2}))|Z)?)?$/;
	}

	var match = dojo.date.stamp._isoRegExp.exec(formattedString);
	var result = null;

	if(match){
		match.shift();
		match[1] && match[1]--; // Javascript Date months are 0-based
		match[6] && (match[6] *= 1000); // Javascript Date expects fractional seconds as milliseconds

		if(defaultTime){
			// mix in defaultTime.  Relatively expensive, so use || operators for the fast path of defaultTime === 0
			defaultTime = new Date(defaultTime);
			dojo.map(["FullYear", "Month", "Date", "Hours", "Minutes", "Seconds", "Milliseconds"], function(prop){
				return defaultTime["get" + prop]();
			}).forEach(function(value, index){
				if(match[index] === undefined){
					match[index] = value;
				}
			});
		}
		result = new Date(match[0]||1970, match[1]||0, match[2]||0, match[3]||0, match[4]||0, match[5]||0, match[6]||0);

		var offset = 0;
		var zoneSign = match[7] && match[7].charAt(0);
		if(zoneSign != 'Z'){
			offset = ((match[8] || 0) * 60) + (Number(match[9]) || 0);
			if(zoneSign != '-'){ offset *= -1; }
		}
		if(zoneSign){
			offset -= result.getTimezoneOffset();
		}
		if(offset){
			result.setTime(result.getTime() + offset * 60000);
		}
	}

	return result; // Date or null
}

dojo.date.stamp.toISOString = function(/*Date*/dateObject, /*Object?*/options){
	//	summary:
	//		Format a Date object as a string according a subset of the ISO-8601 standard
	//
	//	description:
	//		When options.selector is omitted, output follows RFC3339 (http://www.ietf.org/rfc/rfc3339.txt)
	//		Times are formatted using the local time zone.  Does not check bounds.
	//
	//	dateObject:
	//		A Date object
	//
	//	object {selector: string, zulu: boolean, milliseconds: boolean}
	//		selector- "date" or "time" for partial formatting of the Date object.
	//			Both date and time will be formatted by default.
	//		zulu- if true, UTC/GMT is used for a timezone
	//		milliseconds- if true, output milliseconds

	var _ = function(n){ return (n < 10) ? "0" + n : n; }
	options = options || {};
	var formattedDate = [];
	var getter = options.zulu ? "getUTC" : "get";
	var date = "";
	if(options.selector != "time"){
		date = [dateObject[getter+"FullYear"](), _(dateObject[getter+"Month"]()+1), _(dateObject[getter+"Date"]())].join('-');
	}
	formattedDate.push(date);
	if(options.selector != "date"){
		var time = [_(dateObject[getter+"Hours"]()), _(dateObject[getter+"Minutes"]()), _(dateObject[getter+"Seconds"]())].join(':');
		var millis = dateObject[getter+"Milliseconds"]();
		if(options.milliseconds){
			time += "."+ (millis < 100 ? "0" : "") + _(millis);
		}
		if(options.zulu){
			time += "Z";
		}else{
			var timezoneOffset = dateObject.getTimezoneOffset();
			var absOffset = Math.abs(timezoneOffset);
			time += (timezoneOffset > 0 ? "-" : "+") + 
				_(Math.floor(absOffset/60)) + ":" + _(absOffset%60);
		}
		formattedDate.push(time);
	}
	return formattedDate.join('T'); // String
}

