/* * jQuery One Page Nav Plugin * http://github.com/davist11/jQuery-One-Page-Nav * * Copyright (c) 2010 Trevor Davis (http://trevordavis.net) * Dual licensed under the MIT and GPL licenses. * Uses the same license as jQuery, see: * http://jquery.org/license * * @version 3.0.0 * * Example usage: * $('#nav').onePageNav({ *   currentClass: 'current', *   changeHash: false, *   scrollSpeed: 750 * }); */
; (function ($, window, document, undefined) {
    // our plugin constructor    var OnePageNav = function (elem, options) {        this.elem = elem;        this.$elem = $(elem);        this.options = options;        this.metadata = this.$elem.data('plugin-options');        this.$win = $(window);        this.sections = {};        this.didScroll = false;        this.$doc = $(document);        this.docHeight = this.$doc.height();    };
    // the plugin prototype    OnePageNav.prototype = {        defaults: {            navItems: 'a',            currentClass: 'current',            changeHash: false,            easing: 'swing',            filter: '',			navHeight: 75,            scrollSpeed: 750,            scrollThreshold: 0.5,            begin: false,            end: false,            scrollChange: false        },
        init: function () {            // Introduce defaults that can be extended either            // globally or using an object literal.            this.config = $.extend({}, this.defaults, this.options, this.metadata);
            this.$nav = this.$elem.find(this.config.navItems);
            //Filter any links out of the nav            if (this.config.filter !== '') {                this.$nav = this.$nav.filter(this.config.filter);            }
            //Handle clicks on the nav            this.$nav.on('click.onePageNav', $.proxy(this.handleClick, this));
            //Get the section positions            this.getPositions();
            //Handle scroll changes            this.bindInterval();
            //Update the positions on resize too            this.$win.on('resize.onePageNav', $.proxy(this.getPositions, this));
            return this;        },
        adjustNav: function (self, $parent) {            self.$elem.find('.' + self.config.currentClass).removeClass(self.config.currentClass);            $parent.addClass(self.config.currentClass);        },
        bindInterval: function () {            var self = this;            var docHeight;
            self.$win.on('scroll.onePageNav', function () {                self.didScroll = true;            });
            self.t = setInterval(function () {                docHeight = self.$doc.height();
                //If it was scrolled                if (self.didScroll) {                    self.didScroll = false;                    self.scrollChange();                }
                //If the document height changes                if (docHeight !== self.docHeight) {                    self.docHeight = docHeight;                    self.getPositions();                }            }, 250);        },
        getHash: function ($link) {            return $link.attr('href').split('#')[1];        },
        getPositions: function () {            var self = this;            var linkHref;            var topPos;            var $target;
            self.$nav.each(function () {                linkHref = self.getHash($(this));                $target = $('#' + linkHref);
                if ($target.length) {                    topPos = $target.offset().top;
                    self.sections[linkHref] = Math.round(topPos);                }            });        },
        getSection: function (windowPos) {            var returnValue = null;            var windowHeight = Math.round(this.$win.height() * this.config.scrollThreshold);

            for (var section in this.sections) {                if ((this.sections[section] - windowHeight) < windowPos) {                    returnValue = section;										                }            }
            return returnValue;        },
        handleClick: function (e) {            var self = this;            var $link = $(e.currentTarget);            var $parent = $link.parent();            var newLoc = '#' + self.getHash($link);
            if (!$parent.hasClass(self.config.currentClass)) {                //Start callback                if (self.config.begin) {                    self.config.begin();                }
                //Change the highlighted nav item                self.adjustNav(self, $parent);
                //Removing the auto-adjust on scroll                self.unbindInterval();
                //Scroll to the correct position                self.scrollTo(newLoc, function () {                    //Do we need to change the hash?                    if (self.config.changeHash) {                        window.location.hash = newLoc;                    }//				$('#aboutUs').offset({'top':'60'});                    //Add the auto-adjust on scroll back in                    self.bindInterval();
                    //End callback                    if (self.config.end) {                        self.config.end();                    }                });            }
            e.preventDefault();        },
        scrollChange: function () {            var windowTop = this.$win.scrollTop();            var position = this.getSection(windowTop);            var $parent;
            //If the position is set            if (position !== null) {                $parent = this.$elem.find('a[href$="#' + position + '"]').parent();
                //If it's not already the current section                if (!$parent.hasClass(this.config.currentClass)) {                    //Change the highlighted nav item                    this.adjustNav(this, $parent);
                    //If there is a scrollChange callback                    if (this.config.scrollChange) {                        this.config.scrollChange($parent);                    }                }            }        },
        scrollTo: function (target, callback) {            var offset = $(target).offset().top - this.config.navHeight;            $('html, body').animate({                scrollTop: offset            }, this.config.scrollSpeed, this.config.easing, callback);        },
        unbindInterval: function () {            clearInterval(this.t);            this.$win.unbind('scroll.onePageNav');        }    };
    OnePageNav.defaults = OnePageNav.prototype.defaults;
    $.fn.onePageNav = function (options) {        return this.each(function () {            new OnePageNav(this, options).init();        });    };
})(jQuery, window, document);