/** 
 * @fileOverview Helper methods to refactor code and make life easier.
 * @author Tom McCourt / Oliver Bishop
 * @version 1.0.11
 * @changeLog changed PNGFix method name and added an IE6 YUI detection to prevent errors in browsers and remove need for conditional comments with YUI get script method.
 */

var UKISA = UKISA || {util: {}};
/**
 * @namespace Helper methods.
 * @memberOf UKISA.utils
 */
UKISA.util = {
	/**
	 * Proxy for a PNG fix script. In this case BelatedPNGFix is used.
	 *
	 * @param {String} t Comma seperated list of element IDs to use to apply the PNG fix to.
	 * @param {String} url By default the URL to the png script is the new site standard /web/scripts/png_fix.js. If this is not the case, specify an alternative.
	 * @requires YAHOO.util.Get
	 */
	PNGFix: function(t, url) {
		var get, getURL;

		if (YAHOO && YAHOO.env.ua.ie === 6) {
			getURL = url || "/web/scripts/png_fix.js";
			get = YAHOO.util.Get.script(getURL, { 
				onSuccess: function() { 
					if (typeof DD_belatedPNG !== "undefined") {
						DD_belatedPNG.fix(t);
					} else {
						alert("Missing PNG handler");
					}
				}
			});
		}
	},
	/** 
	 * Opens a system print dialogue box.
	 *
	 * @param {Boolean} Returns false;
	 */
	print: function() {
		if (window.print) {
			window.print();
		}
		return false;
	},
	/**
	 * Apply a class of "nth-child" to a frequency of a collection of items.
	 *
	 * @memberOf UKISA.utils
	 * @param {Object} list Collection of enumerable objects.
	 * @param {Integer} freq The nth item in the list to apply the class to.
	 */
	nthChild: function(list, freq) {
		for (var i = 0, ix = list.length; i < ix; i++) {
			if ((i + 1) % freq == 0) {
				YAHOO.util.Dom.addClass(list[i], "nth-child"); 
			} else {
				YAHOO.util.Dom.removeClass(list[i], "nth-child"); 
			}
		}
	},
	/**
	 * Clear the default text on a textbox when focus is gained.
	 *
	 * @memberOf UKISA.utils
	 * @param {String} Unlimited list of arguments for inputs to apply this to
	 */
	clearDefault: function () {
		var action = function(el) {
			if (!el) { return; }

			var defaultValue = el.value;

			el.onfocus = function() {
				var old = defaultValue;
				if (this.value === defaultValue) {
					this.value = "";
				}
			};

			el.onblur = function() {
				var old = defaultValue;
				if (this.value === "" || this.value === defaultValue) {
					this.value = old;
				}
			};
		};

		for (var i = 0, ix = arguments.length; i < ix; i++) {
			action(document.getElementById(arguments[i]));
		}
	},
	/**
	 * Gets the real parent node of an element, skipping inapporpriate node types e.g. whitespace as used in IE.
	 *
	 * @memberOf UKISA.utils
	 * @param {String|HTMLObject} el Element to find the parent node of.
	 * @returns {HTMLObject} The real parent node of the element.
	 */
	parentNode: function(el) {
		var e = (typeof el == "string") ? document.getElementById(el) : el;
		var node = null;
		if (e && e.parentNode) {
			while (e.parentNode.nodeType != 1) {
				e = e.parentNode;
				node = e;
			}
			return (!node) ? e.parentNode : node;
		}
	},
	/**
	 * Remove white space before or after a string
	 *
	 * @memberOf UKISA.utils
	 * @param {String} s String to trim white space from
	 * @return {String}	 Returns a clean string with white space removed
	 */
	trim: function(s) {
		return s.replace(/^\s+|\s+$/g, "");
	},
	/**
	 * Get the scroll position of the document.
	 *
	 * @memberOf UKISA.utils
	 * @deprecated Use the YAHOO.util.Dom.getDocumentScrollLeft(), YAHOO.util.Dom.getDocumentScrollTop() instead.
	 * @return {Array}	 Array [0] is the left scroll in pixels, [1] is the top scroll in pixels.
	 */
	getScrollXY: function() { // Get scroll position of page
		var scrOfX = 0, scrOfY = 0;
		if(typeof(window.pageYOffset) === "number") {
			//Netscape compliant
			scrOfY = window.pageYOffset;
			scrOfX = window.pageXOffset;
		} else if(document.body && (document.body.scrollLeft || document.body.scrollTop)) {
			//DOM compliant
			scrOfY = document.body.scrollTop;
			scrOfX = document.body.scrollLeft;
		} else if(document.documentElement && (document.documentElement.scrollLeft || document.documentElement.scrollTop)) {
			//IE6 standards compliant mode
			scrOfY = document.documentElement.scrollTop;
			scrOfX = document.documentElement.scrollLeft;
		}
		return [scrOfX, scrOfY];
	}
};