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/*!

 * jScroll - jQuery Plugin for Infinite Scrolling / Auto-Paging

 * http://jscroll.com/

 *

 * Copyright 2011-2013, Philip Klauzinski

 * http://klauzinski.com/

 * Dual licensed under the MIT and GPL Version 2 licenses.

 * http://jscroll.com/#license

 * http://www.opensource.org/licenses/mit-license.php

 * http://www.gnu.org/licenses/gpl-2.0.html

 *

 * @author Philip Klauzinski

 * @version 2.3.4

 * @requires jQuery v1.4.3+

 * @preserve

 */

(function($) {

    'use strict';

    // Define the jscroll namespace and default settings

    $.jscroll = {

        defaults: {

            debug: false,

            autoTrigger: true,

            autoTriggerUntil: false,

            loadingHtml: '<small>Loading...</small>',

            padding: 0,

            nextSelector: 'a:last',

            contentSelector: '',

            pagingSelector: '',

            callback: false

        }

    };

    // Constructor

    var jScroll = function($e, options) {

        // Private vars and methods

        var _data = $e.data('jscroll'),

            _userOptions = (typeof options === 'function') ? { callback: options } : options,

            _options = $.extend({}, $.jscroll.defaults, _userOptions, _data || {}),

            _isWindow = ($e.css('overflow-y') === 'visible'),

            _$next = $e.find(_options.nextSelector).first(),

            _$window = $(window),

            _$body = $('body'),

            _$scroll = _isWindow ? _$window : $e,

            _nextHref = $.trim(_$next.attr('href') + ' ' + _options.contentSelector),

            // Check if a loading image is defined and preload

            _preloadImage = function() {

                var src = $(_options.loadingHtml).filter('img').attr('src');

                if (src) {

                    var image = new Image();

                    image.src = src;

                }

            },

            // Wrap inner content, if it isn't already

            _wrapInnerContent = function() {

                if (!$e.find('.jscroll-inner').length) {

                    $e.contents().wrapAll('<div class="jscroll-inner" />');

                }

            },

            // Find the next link's parent, or add one, and hide it

            _nextWrap = function($next) {

                var $parent;

                if (_options.pagingSelector) {

                    $next.closest(_options.pagingSelector).hide();

                } else {

                    $parent = $next.parent().not('.jscroll-inner,.jscroll-added').addClass('jscroll-next-parent').hide();

                    if (!$parent.length) {

                        $next.wrap('<div class="jscroll-next-parent" />').parent().hide();

                    }

                }

            },

            // Remove the jscroll behavior and data from an element

            _destroy = function() {

                return _$scroll.unbind('.jscroll')

                    .removeData('jscroll')

                    .find('.jscroll-inner').children().unwrap()

                    .filter('.jscroll-added').children().unwrap();

            },

            // Observe the scroll event for when to trigger the next load

            _observe = function() {

                _wrapInnerContent();

                var $inner = $e.find('div.jscroll-inner').first(),

                    data = $e.data('jscroll'),

                    borderTopWidth = parseInt($e.css('borderTopWidth'), 10),

                    borderTopWidthInt = isNaN(borderTopWidth) ? 0 : borderTopWidth,

                    iContainerTop = parseInt($e.css('paddingTop'), 10) + borderTopWidthInt,

                    iTopHeight = _isWindow ? _$scroll.scrollTop() : $e.offset().top,

                    innerTop = $inner.length ? $inner.offset().top : 0,

                    iTotalHeight = Math.ceil(iTopHeight - innerTop + _$scroll.height() + iContainerTop);

                if (!data.waiting && iTotalHeight + _options.padding >= $inner.outerHeight()) {

                    //data.nextHref = $.trim(data.nextHref + ' ' + _options.contentSelector);

                    _debug('info', 'jScroll:', $inner.outerHeight() - iTotalHeight, 'from bottom. Loading next request...');

                    return _load();

                }

            },

            // Check if the href for the next set of content has been set

            _checkNextHref = function(data) {

                data = data || $e.data('jscroll');

                if (!data || !data.nextHref) {

                    _debug('warn', 'jScroll: nextSelector not found - destroying');

                    _destroy();

                    return false;

                } else {

                    _setBindings();

                    return true;

                }

            },

            _setBindings = function() {

                var $next = $e.find(_options.nextSelector).first();

                if (!$next.length) {

                    return;

                }

                if (_options.autoTrigger && (_options.autoTriggerUntil === false || _options.autoTriggerUntil > 0)) {

                    _nextWrap($next);

                    if (_$body.height() <= _$window.height()) {

                        _observe();

                    }

                    _$scroll.unbind('.jscroll').bind('scroll.jscroll', function() {

                        return _observe();

                    });

                    if (_options.autoTriggerUntil > 0) {

                        _options.autoTriggerUntil--;

                    }

                } else {

                    _$scroll.unbind('.jscroll');

                    $next.bind('click.jscroll', function() {

                        _nextWrap($next);

                        _load();

                        return false;

                    });

                }

            },

            // Load the next set of content, if available

            _load = function() {

                var $inner = $e.find('div.jscroll-inner').first(),

                    data = $e.data('jscroll');

                data.waiting = true;

                $inner.append('<div class="jscroll-added" />')

                    .children('.jscroll-added').last()

                    .html('<div class="jscroll-loading">' + _options.loadingHtml + '</div>');

                return $e.animate({scrollTop: $inner.outerHeight()}, 0, function() {

                    $inner.find('div.jscroll-added').last().load(data.nextHref, function(r, status) {

                        if (status === 'error') {

                            return _destroy();

                        }

                        var $next = $(this).find(_options.nextSelector).first();

                        data.waiting = false;

                        data.nextHref = $next.attr('href') ? $.trim($next.attr('href') + ' ' + _options.contentSelector) : false;

                        $('.jscroll-next-parent', $e).remove(); // Remove the previous next link now that we have a new one

                        _checkNextHref();

                        if (_options.callback) {

                            _options.callback.call(this);

                        }

                        _debug('dir', data);

                    });

                });

            },

            // Safe console debug - http://klauzinski.com/javascript/safe-firebug-console-in-javascript

            _debug = function(m) {

                if (_options.debug && typeof console === 'object' && (typeof m === 'object' || typeof console[m] === 'function')) {

                    if (typeof m === 'object') {

                        var args = [];

                        for (var sMethod in m) {

                            if (typeof console[sMethod] === 'function') {

                                args = (m[sMethod].length) ? m[sMethod] : [m[sMethod]];

                                console[sMethod].apply(console, args);

                            } else {

                                console.log.apply(console, args);

                            }

                        }

                    } else {

                        console[m].apply(console, Array.prototype.slice.call(arguments, 1));

                    }

                }

            };

        // Initialization

        $e.data('jscroll', $.extend({}, _data, {initialized: true, waiting: false, nextHref: _nextHref}));

        _wrapInnerContent();

        _preloadImage();

        _setBindings();

        // Expose API methods via the jQuery.jscroll namespace, e.g. $('sel').jscroll.method()

        $.extend($e.jscroll, {

            destroy: _destroy,

            bind : _setBindings

        });

        return $e;

    };

    // Define the jscroll plugin method and loop

    $.fn.jscroll = function(m) {

        return this.each(function() {

            var $this = $(this),

                data = $this.data('jscroll'), jscroll;

            // Instantiate jScroll on this element if it hasn't been already

            if (data && data.initialized) {

                return;

            }

            jscroll = new jScroll($this, m);

        });

    };

})(jQuery);