/*!
 * jQuery Divide Plugin
 * Copyright (c) 2010 Eli Dupuis
 * Version: 0.3 (June 16, 2010)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php) and GPL (http://creativecommons.org/licenses/GPL/2.0/) licenses.
 * Requires: jQuery v1.3.2 or later
 */

(function($) {

var ver = '0.3';

jQuery.fn.divide = function(options) {

	// iterate and reformat each matched element
	return this.each(function() {
		var $this = $(this),
			opts = $.extend({}, $.fn.divide.defaults, options),
			elm;

		if (opts.target) {
			elm = $this.find(opts.target);
		}else{
			elm = $this;
		};
		
		//	set vars that will be used throughout:
		var childr = elm.children();
		var numChildr = childr.length;

		//	only proceed if number of children is higher than threshold:
		if (numChildr > opts.threshold) {
			
			//	retrieve original element type
			var elmType = elm[0].nodeName;
			//	determine minimum number of children to be in each column:
			var minPerCol = Math.floor(numChildr / opts.cols);
			//	determine number of columns that will house extra children 
			var tallCols = numChildr % opts.cols;

			var wrapper;
			if (opts.target) {
				//	use existing parent element.
				wrapper = elm.parent();
			}else{
				//	create wrapper element.
				wrapper = $('<' +  opts.wrapper + '>');
			};
			
			//	retain classes and ids from original element:
			if (elm.attr('class')) wrapper.attr('class',elm.attr('class'));
			if (elm.attr('id')) wrapper.attr('id',elm.attr('id'));
			
			//	loop through specified number of columns:
			for (var i=0; i < opts.cols; i++) {
				
				//	determine number of elements to get for this column:
				var itemsToGet = minPerCol;
				if (i < tallCols) itemsToGet = minPerCol + 1;

				//	create new element for this column:
				var thisList = $('<' + elmType + ' class="' + opts.classPrefix + (i+1) + '">');
				//	add desired children to new element:
				thisList.append(childr.slice(0,itemsToGet));
				//	add new element to temp container:
				wrapper.append(thisList);
				
				//	filter newly added children out original children:
				childr = childr.filter(':gt(' + (itemsToGet - 1) + ')');
			};

			//	clean up and place new children or remove stray parents:
			if (opts.target) {
				//	remove original parent. new children have already been placed.
				elm.remove();
			}else{
				//	replace original parent element with freshly created children elements.
				elm.replaceWith(wrapper);
			};

		};
	});
};	

//	defaults
$.fn.divide.defaults = {
	threshold: 1,			//	only act if number of children is greater than this number
	cols: 2,				//	number of columns to create out of initial items
	classPrefix: 'column-',	//	prefix used to identify offspring elements
	wrapper: 'div',			//	type of element that should be used to wrap divided children
	target: null			//	expression for selecting child (if something other than all children is required)
};

//	public function/method
$.fn.divide.ver = function() { return "jquery.divide ver. " + ver; };
	
// end of closure
})(jQuery);