/*!
 * jQuery UI Effects Explode @VERSION
 *
 * Copyright 2012, AUTHORS.txt (http://jqueryui.com/about)
 * Dual licensed under the MIT or GPL Version 2 licenses.
 * http://jquery.org/license
 *
 * http://docs.jquery.com/UI/Effects/Explode
 *
 * Depends:
 *	jquery.effects.core.js
 */
(function( $, undefined ) {

$.effects.effect.explode = function( o, done ) {

	var rows = o.pieces ? Math.round( Math.sqrt( o.pieces ) ) : 3,
		cells = rows,
		el = $( this ),
		mode = $.effects.setMode( el, o.mode || "hide" ),
		show = mode === "show",

		// show and then visibility:hidden the element before calculating offset
		offset = el.show().css( "visibility", "hidden" ).offset(),

		// width and height of a piece
		width = Math.ceil( el.outerWidth() / cells ),
		height = Math.ceil( el.outerHeight() / rows ),
		pieces = [],

		// loop
		i, j, left, top, mx, my;

	// children animate complete:
	function childComplete() {
		pieces.push( this );
		if ( pieces.length === rows * cells ) {
			animComplete();
		}
	}

	// clone the element for each row and cell.
	for( i = 0; i < rows ; i++ ) { // ===>
		top = offset.top + i * height;
		my = i - ( rows - 1 ) / 2 ;

		for( j = 0; j < cells ; j++ ) { // |||
			left = offset.left + j * width;
			mx = j - ( cells - 1 ) / 2 ;

			// Create a clone of the now hidden main element that will be absolute positioned
			// within a wrapper div off the -left and -top equal to size of our pieces
			el
				.clone()
				.appendTo( "body" )
				.wrap( "<div></div>" )
				.css({
					position: "absolute",
					visibility: "visible",
					left: -j * width,
					top: -i * height
				})

			// select the wrapper - make it overflow: hidden and absolute positioned based on
			// where the original was located +left and +top equal to the size of pieces
				.parent()
				.addClass( "ui-effects-explode" )
				.css({
					position: "absolute",
					overflow: "hidden",
					width: width,
					height: height,
					left: left + ( show ? mx * width : 0 ),
					top: top + ( show ? my * height : 0 ),
					opacity: show ? 0 : 1
				}).animate({
					left: left + ( show ? 0 : mx * width ),
					top: top + ( show ? 0 : my * height ),
					opacity: show ? 1 : 0
				}, o.duration || 500, o.easing, childComplete );
		}
	}

	function animComplete() {
		el.css({
			visibility: "visible"
		});
		$( pieces ).remove();
		if ( !show ) {
			el.hide();
		}
		done();
	}
};

})(jQuery);
