/**
 * TabControl plugin for jQuery
 * v1.0
 * Implements an tabbed control box
 *
 * By Craig Buckler, Optimalworks.net
 *
 * As featured on SitePoint.com:
 * http://www.sitepoint.com/
 *
 * Please use at your own risk.
 */

/**
 * Usage:
 *
 * From JavaScript, use:
 *     $(<node>).TabControl();
 *     where:
 *       <node> is a list of links to tabbed content
 *
 * Alternatively, in you HTML:
 *     Assign a class of "tabs" to any <ol> or <ul> tag that contains a list of on-page links.
 */

(function($) {

	// jQuery plugin definition
	$.fn.TabControl = function() {

		// tab control object
		function TabControl(list) {

			if (list.TabControlInitialized) return;
			else list.TabControlInitialized = true;

			this.List = list;
			this.Tab = {};
			this.Active = null;
			var T = this;

			// find and initialize all tabs
			$("li a[href^=#]", list).each(function() {

				var id = T.LinkId(this);
				var content = $("#"+id);
				content = (content.length > 0 ? content[0] : null);

				// link/content object
				T.Tab[id] = {
					link: this,
					content: content
				};

				// set content holder class
				if (content !== null) $(content.parentNode).addClass("active");

				// event delegation
				$("a[href=#"+id+"]").click(function(e) { T.TabSwitch(e) });

				// deactivate tab
				T.Activate(id, false);

				// is tab active?
				if (T.Active === null || "#"+id == location.hash) T.Active = id;

			});

			// show active tab/content
			this.Activate(this.Active);

		}


		// returns linked ID
		TabControl.prototype.LinkId = function(link) {
			return link.href.replace(/.*#(.+)$/, "$1");
		};


		// tab click event handler
		TabControl.prototype.TabSwitch = function(e) {

			e.preventDefault();

			var id = this.LinkId(e.target);
			if (id != this.Active) {

				// hide old tab
				this.Activate(this.Active, false);

				// switch to new tab
				this.Active = id;
				this.Activate(this.Active);

			}

			// scroll to tab box if required
			var html = $('html,body');
			var lt = $(this.List).offset().top, lh = $(this.List).height();
			var st = Math.max(html.scrollTop(), $("body").scrollTop()), wh = $(window).height();
			if (lt < st || lt+lh > st+wh) html.animate({scrollTop: lt}, 500);

			return false;
		};


		// activate or deactivate a tab
		TabControl.prototype.Activate = function(id, show) {

			if (this.Tab[id]) {
				if (show !== false) {
					$(this.Tab[id].link).addClass("active");
					if (this.Tab[id].content) this.Tab[id].content.style.display = "block";
				}
				else {
					$(this.Tab[id].link).removeClass("active");
					if (this.Tab[id].content) this.Tab[id].content.style.display = "none";
				}
			}

		};


		// initialize all tab controls
		this.each(function() { new TabControl(this); });
		return this;
	};

})(jQuery);