/*!

 * scrollup v2.4.1

 * Url: http://markgoodyear.com/labs/scrollup/

 * Copyright (c) Mark Goodyear — @markgdyr — http://markgoodyear.com

 * License: MIT

 */

(function ($, window, document) {

    'use strict';



    // Main function

    $.fn.scrollUp = function (options) {



        // Ensure that only one scrollUp exists

        if (!$.data(document.body, 'scrollUp')) {

            $.data(document.body, 'scrollUp', true);

            $.fn.scrollUp.init(options);

        }

    };



    // Init

    $.fn.scrollUp.init = function (options) {



        // Define vars

        var o = $.fn.scrollUp.settings = $.extend({}, $.fn.scrollUp.defaults, options),

            triggerVisible = false,

            animIn, animOut, animSpeed, scrollDis, scrollEvent, scrollTarget, $self;



        // Create element

        if (o.scrollTrigger) {

            $self = $(o.scrollTrigger);

        } else {

            $self = $('<a/>', {

                id: o.scrollName,

                href: '#top'

            });

        }



        // Set scrollTitle if there is one

        if (o.scrollTitle) {

            $self.attr('title', o.scrollTitle);

        }



        $self.appendTo('body');



        // If not using an image display text

        if (!(o.scrollImg || o.scrollTrigger)) {

            $self.html(o.scrollText);

        }



        // Minimum CSS to make the magic happen

        $self.css({

            display: 'none',

            position: 'fixed',

            zIndex: o.zIndex

        });



        // Active point overlay

        if (o.activeOverlay) {

            $('<div/>', {

                id: o.scrollName + '-active'

            }).css({

                position: 'absolute',

                'top': o.scrollDistance + 'px',

                width: '100%',

                borderTop: '1px dotted' + o.activeOverlay,

                zIndex: o.zIndex

            }).appendTo('body');

        }



        // Switch animation type

        switch (o.animation) {

            case 'fade':

                animIn = 'fadeIn';

                animOut = 'fadeOut';

                animSpeed = o.animationSpeed;

                break;



            case 'slide':

                animIn = 'slideDown';

                animOut = 'slideUp';

                animSpeed = o.animationSpeed;

                break;



            default:

                animIn = 'show';

                animOut = 'hide';

                animSpeed = 0;

        }



        // If from top or bottom

        if (o.scrollFrom === 'top') {

            scrollDis = o.scrollDistance;

        } else {

            scrollDis = $(document).height() - $(window).height() - o.scrollDistance;

        }



        // Scroll function

        scrollEvent = $(window).scroll(function () {

            if ($(window).scrollTop() > scrollDis) {

                if (!triggerVisible) {

                    $self[animIn](animSpeed);

                    triggerVisible = true;

                }

            } else {

                if (triggerVisible) {

                    $self[animOut](animSpeed);

                    triggerVisible = false;

                }

            }

        });



        if (o.scrollTarget) {

            if (typeof o.scrollTarget === 'number') {

                scrollTarget = o.scrollTarget;

            } else if (typeof o.scrollTarget === 'string') {

                scrollTarget = Math.floor($(o.scrollTarget).offset().top);

            }

        } else {

            scrollTarget = 0;

        }



        // To the top

        $self.click(function (e) {

            e.preventDefault();



            $('html, body').animate({

                scrollTop: scrollTarget

            }, o.scrollSpeed, o.easingType);

        });

    };



    // Defaults

    $.fn.scrollUp.defaults = {

        scrollName: 'scrollUp',      // Element ID

        scrollDistance: 300,         // Distance from top/bottom before showing element (px)

        scrollFrom: 'top',           // 'top' or 'bottom'

        scrollSpeed: 300,            // Speed back to top (ms)

        easingType: 'linear',        // Scroll to top easing (see http://easings.net/)

        animation: 'fade',           // Fade, slide, none

        animationSpeed: 200,         // Animation in speed (ms)

        scrollTrigger: false,        // Set a custom triggering element. Can be an HTML string or jQuery object

        scrollTarget: false,         // Set a custom target element for scrolling to. Can be element or number

        scrollText: 'Scroll to top', // Text for element, can contain HTML

        scrollTitle: false,          // Set a custom <a> title if required. Defaults to scrollText

        scrollImg: false,            // Set true to use image

        activeOverlay: false,        // Set CSS color to display scrollUp active point, e.g '#00FFFF'

        zIndex: 2147483647           // Z-Index for the overlay

    };



    // Destroy scrollUp plugin and clean all modifications to the DOM

    $.fn.scrollUp.destroy = function (scrollEvent) {

        $.removeData(document.body, 'scrollUp');

        $('#' + $.fn.scrollUp.settings.scrollName).remove();

        $('#' + $.fn.scrollUp.settings.scrollName + '-active').remove();



        // If 1.7 or above use the new .off()

        if ($.fn.jquery.split('.')[1] >= 7) {

            $(window).off('scroll', scrollEvent);



        // Else use the old .unbind()

        } else {

            $(window).unbind('scroll', scrollEvent);

        }

    };



    $.scrollUp = $.fn.scrollUp;



})(jQuery, window, document);