/*

scrollup v1.0.0
author: mark goodyear - http://www.markgoodyear.com
git: https://github.com/markgoodyear/scrollup

copyright 2013 mark goodyear
licensed under the mit license
http://www.opensource.org/licenses/mit-license.php

twitter: @markgdyr

*/

;(function ($) {

	$.scrollup = function (options) {

		// settings
		var settings = {
			scrollname: 'scrollup', // element id
			topdistance: '300', // distance from top before showing element (px)
			topspeed: 300, // speed back to top (ms)
			animation: 'fade', // fade, slide, none
			animationinspeed: 200, // animation in speed (ms)
			animationoutspeed: 200, // animation out speed (ms)
			scrolltext: 'scroll to top', // text for element
			activeoverlay: false // set css color to display scrollup active point, e.g '#00ffff'
		};

		// load settings
		if (options) {
			var settings = $.extend(settings, options);
		}

		// shorthand setting names
		var sn = '#' + settings.scrollname,
			an = settings.animation,
			os = settings.animationoutspeed,
			is = settings.animationinspeed,
			td = settings.topdistance,
			st = settings.scrolltext,
			ts = settings.topspeed,
			ao = settings.activeoverlay;

		// create element
		$('<a/>', {
		    id: settings.scrollname,
		    href: '#top',
		    title: st,
		    text: st
		}).appendto('.plane-bd li.last');

		// minium css to make the magic happen
		$(sn).css({
			'display':'none',
//			'position': 'fixed',
			'z-index': '2147483647'
		})

		// active point overlay
		if (ao) {
			$("body").append("<div id='"+ settings.scrollname +"-active'></div>");
			$(sn+"-active").css({ 'position': 'absolute', 'top': td+'px', 'width': '100%', 'border-top': '1px dotted '+ao, 'z-index': '2147483647' })
		}

		// scroll funtion
		$(window).scroll(function(){	

			// fade animation
			if (an === "fade") {
				$( ($(window).scrolltop() > td) ? $(sn).fadein(is) : $(sn).fadeout(os) );
			}

			// slideup animation
			else if (an === "slide") {
				$( ($(window).scrolltop() > td) ? $(sn).slidedown(is) : $(sn).slideup(os) );
			}

			// no animation
			else {
				$( ($(window).scrolltop() > td) ? $(sn).show(0) : $(sn).hide(0) );
			}

		});

		// back to the top
		$(sn).click( function(event) {
		  	$('html, body').animate({scrolltop:0}, ts);
	        return false;
		});

	}; // end scrollup function
}(jquery));