/*
--------------------------------
Infinite Scroll
--------------------------------
+ https://github.com/paulirish/infinite-scroll
+ version 2.0b2.111027
+ Copyright 2011 Paul Irish & Luke Shumard
+ Licensed under the MIT license
	
+ Documentation: http://infinite-scroll.com/
	
*/

(function (window, $, undefined) {

	$.infinitescroll = function infscr(options, callback, element) {

		this.element = $(element);
		this._create(options, callback);

	};

	$.infinitescroll.defaults = {
		loading: {
			finished: undefined,
			finishedMsg: "<em>Congratulations, you've reached the end of the internet.</em>",
			img: "http://www.infinite-scroll.com/loading.gif",
			msg: null,
			msgText: "<em>Loading the next set of posts...</em>",
			selector: null,
			speed: 'fast',
			start: undefined
		},
		state: {
			isDuringAjax: false,
			isInvalidPage: false,
			isDestroyed: false,
			isDone: false, // For when it goes all the way through the archive.
			isPaused: false,
			currPage: 1
		},
		callback: undefined,
		debug: false,
		behavior: undefined,
		binder: $(window), // used to cache the selector
		nextSelector: "div.navigation a:first",
		navSelector: "div.navigation",
		contentSelector: null, // rename to pageFragment
		extraScrollPx: 150,
		itemSelector: "div.post",
		animate: false,
		pathParse: undefined,
		dataType: 'html',
		appendCallback: true,
		bufferPx: 40,
		errorCallback: function () { },
		infid: 0, //Instance ID
		pixelsFromNavToBottom: undefined,
		path: undefined
	};


	$.infinitescroll.prototype = {

		/*	
		----------------------------
		Private methods
		----------------------------
		*/

		// Bind or unbind from scroll
		_binding: function infscr_binding(binding) {

			var instance = this,
				opts = instance.options;

			opts.v = '2.0b2.111027';

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_binding_' + opts.behavior] !== undefined) {
				this['_binding_' + opts.behavior].call(this);
				return;
			}

			if (binding !== 'bind' && binding !== 'unbind') {
				this._debug('Binding value  ' + binding + ' not valid')
				return false;
			}

			if (binding == 'unbind') {

				(this.options.binder).unbind('smartscroll.infscr.' + instance.options.infid);

			} else {

				(this.options.binder)[binding]('smartscroll.infscr.' + instance.options.infid, function () {
					instance.scroll();
				});

			};

			this._debug('Binding', binding);

		},

		// Fundamental aspects of the plugin are initialized
		_create: function infscr_create(options, callback) {

			// If selectors from options aren't valid, return false
			if (!this._validate(options)) { return false; }
			// Define options and shorthand
			var opts = this.options = $.extend(true, {}, $.infinitescroll.defaults, options),
			// get the relative URL - everything past the domain name.
				relurl = /(.*?\/\/).*?(\/.*)/,
				path = $(opts.nextSelector).attr('href');

			// contentSelector is 'page fragment' option for .load() / .ajax() calls
			opts.contentSelector = opts.contentSelector || this.element;

			// loading.selector - if we want to place the load message in a specific selector, defaulted to the contentSelector
			opts.loading.selector = opts.loading.selector || opts.contentSelector;

			// if there's not path, return
			if (!path) { this._debug('Navigation selector not found'); return; }

			// Set the path to be a relative URL from root.
			opts.path = this._determinepath(path);

			// Define loading.msg
			opts.loading.msg = $('<div id="infscr-loading"><img alt="Loading..." src="' + opts.loading.img + '" /><div>' + opts.loading.msgText + '</div></div>');

			// Preload loading.img
			(new Image()).src = opts.loading.img;

			// distance from nav links to bottom
			// computed as: height of the document + top offset of container - top offset of nav link
			opts.pixelsFromNavToBottom = $(document).height() - $(opts.navSelector).offset().top;

			// determine loading.start actions
			opts.loading.start = opts.loading.start || function () {

				$(opts.navSelector).hide();
				opts.loading.msg
					.appendTo(opts.loading.selector)
					.show(opts.loading.speed, function () {
						beginAjax(opts);
					});
			};

			// determine loading.finished actions
			opts.loading.finished = opts.loading.finished || function () {
				opts.loading.msg.fadeOut('normal');
			};

			// callback loading
			opts.callback = function (instance, data) {
				if (!!opts.behavior && instance['_callback_' + opts.behavior] !== undefined) {
					instance['_callback_' + opts.behavior].call($(opts.contentSelector)[0], data);
				}
				if (callback) {
					callback.call($(opts.contentSelector)[0], data, opts);
				}
			};

			this._setup();

		},

		// Console log wrapper
		_debug: function infscr_debug() {

			if (this.options && this.options.debug) {
				return window.console && console.log.call(console, arguments);
			}

		},

		// find the number to increment in the path.
		_determinepath: function infscr_determinepath(path) {

			var opts = this.options;

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_determinepath_' + opts.behavior] !== undefined) {
				this['_determinepath_' + opts.behavior].call(this, path);
				return;
			}

			if (!!opts.pathParse) {

				this._debug('pathParse manual');
				return opts.pathParse();

			} else if (path.match(/^(.*?)\b2\b(.*?$)/)) {
				path = path.match(/^(.*?)\b2\b(.*?$)/).slice(1);

				// if there is any 2 in the url at all.    
			} else if (path.match(/^(.*?)2(.*?$)/)) {

				// page= is used in django:
				// http://www.infinite-scroll.com/changelog/comment-page-1/#comment-127
				if (path.match(/^(.*?page=)2(\/.*|$)/)) {
					path = path.match(/^(.*?page=)2(\/.*|$)/).slice(1);
					return path;
				}

				path = path.match(/^(.*?)2(.*?$)/).slice(1);

			} else {

				// page= is used in drupal too but second page is page=1 not page=2:
				// thx Jerod Fritz, vladikoff
				if (path.match(/^(.*?page=)1(\/.*|$)/)) {
					path = path.match(/^(.*?page=)1(\/.*|$)/).slice(1);
					return path;
				} else {
					this._debug('Sorry, we couldn\'t parse your Next (Previous Posts) URL. Verify your the css selector points to the correct A tag. If you still get this error: yell, scream, and kindly ask for help at infinite-scroll.com.');
					// Get rid of isInvalidPage to allow permalink to state
					opts.state.isInvalidPage = true;  //prevent it from running on this page.
				}
			}
			this._debug('determinePath', path);
			return path;

		},

		// Custom error
		_error: function infscr_error(xhr) {

			var opts = this.options;

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_error_' + opts.behavior] !== undefined) {
				this['_error_' + opts.behavior].call(this, xhr);
				return;
			}

			if (xhr !== 'destroy' && xhr !== 'end') {
				xhr = 'unknown';
			}

			this._debug('Error', xhr);

			if (xhr == 'end') {
				this._showdonemsg();
			}

			opts.state.isDone = true;
			opts.state.currPage = 1; // if you need to go back to this instance
			opts.state.isPaused = false;
			this._binding('unbind');

		},

		// Load Callback
		_loadcallback: function infscr_loadcallback(box, data) {

			var opts = this.options,
				callback = this.options.callback, // GLOBAL OBJECT FOR CALLBACK
				result = (opts.state.isDone) ? 'done' : (!opts.appendCallback) ? 'no-append' : 'append',
				frag;

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_loadcallback_' + opts.behavior] !== undefined) {
				this['_loadcallback_' + opts.behavior].call(this, box, data);
				return;
			}

			switch (result) {

				case 'done':

					this._showdonemsg();
					return false;

					break;

				case 'no-append':

					if (opts.dataType == 'html') {
						data = '<div>' + data + '</div>';
						data = $(data).find(opts.itemSelector);
					};

					break;

				case 'append':

					var children = box.children();

					// if it didn't return anything
					if (children.length == 0) {
						return this._error('end');
					}


					// use a documentFragment because it works when content is going into a table or UL
					frag = document.createDocumentFragment();
					while (box[0].firstChild) {
						frag.appendChild(box[0].firstChild);
					}

					this._debug('contentSelector', $(opts.contentSelector)[0])
					$(opts.contentSelector)[0].appendChild(frag);
					// previously, we would pass in the new DOM element as context for the callback
					// however we're now using a documentfragment, which doesnt havent parents or children,
					// so the context is the contentContainer guy, and we pass in an array
					//   of the elements collected as the first argument.

					data = children.get();


					break;

			}

			// loadingEnd function
			opts.loading.finished.call($(opts.contentSelector)[0], opts)


			// smooth scroll to ease in the new content
			if (opts.animate) {
				var scrollTo = $(window).scrollTop() + $('#infscr-loading').height() + opts.extraScrollPx + 'px';
				$('html,body').animate({ scrollTop: scrollTo }, 800, function () { opts.state.isDuringAjax = false; });
			}

			if (!opts.animate) opts.state.isDuringAjax = false; // once the call is done, we can allow it again.

			callback(this, data);

		},

		_nearbottom: function infscr_nearbottom() {

			var opts = this.options,
				pixelsFromWindowBottomToBottom = 0 + $(document).height() - (opts.binder.scrollTop()) - $(window).height();

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_nearbottom_' + opts.behavior] !== undefined) {
				this['_nearbottom_' + opts.behavior].call(this);
				return;
			}

			this._debug('math:', pixelsFromWindowBottomToBottom, opts.pixelsFromNavToBottom);

			// if distance remaining in the scroll (including buffer) is less than the orignal nav to bottom....
			return (pixelsFromWindowBottomToBottom - opts.bufferPx < opts.pixelsFromNavToBottom);

		},

		// Pause / temporarily disable plugin from firing
		_pausing: function infscr_pausing(pause) {

			var opts = this.options;

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_pausing_' + opts.behavior] !== undefined) {
				this['_pausing_' + opts.behavior].call(this, pause);
				return;
			}

			// If pause is not 'pause' or 'resume', toggle it's value
			if (pause !== 'pause' && pause !== 'resume' && pause !== null) {
				this._debug('Invalid argument. Toggling pause value instead');
			};

			pause = (pause && (pause == 'pause' || pause == 'resume')) ? pause : 'toggle';

			switch (pause) {
				case 'pause':
					opts.state.isPaused = true;
					break;

				case 'resume':
					opts.state.isPaused = false;
					break;

				case 'toggle':
					opts.state.isPaused = !opts.state.isPaused;
					break;
			}

			this._debug('Paused', opts.state.isPaused);
			return false;

		},

		// Behavior is determined
		// If the behavior option is undefined, it will set to default and bind to scroll
		_setup: function infscr_setup() {

			var opts = this.options;

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_setup_' + opts.behavior] !== undefined) {
				this['_setup_' + opts.behavior].call(this);
				return;
			}

			this._binding('bind');

			return false;

		},

		// Show done message
		_showdonemsg: function infscr_showdonemsg() {

			var opts = this.options;

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['_showdonemsg_' + opts.behavior] !== undefined) {
				this['_showdonemsg_' + opts.behavior].call(this);
				return;
			}

			opts.loading.msg
				.find('img')
				.hide()
				.parent()
				.find('div').html(opts.loading.finishedMsg).animate({ opacity: 1 }, 2000, function () {
					$(this).parent().fadeOut('normal');
				});

			// user provided callback when done    
			opts.errorCallback.call($(opts.contentSelector)[0], 'done');

		},

		// grab each selector option and see if any fail
		_validate: function infscr_validate(opts) {

			for (var key in opts) {
				if (key.indexOf && key.indexOf('Selector') > -1 && $(opts[key]).length === 0) {
					this._debug('Your ' + key + ' found no elements.');
					return false;
				}
				return true;
			}

		},

		/*	
		----------------------------
		Public methods
		----------------------------
		*/

		// Bind to scroll
		bind: function infscr_bind() {
			this._binding('bind');
		},

		// Destroy current instance of plugin
		destroy: function infscr_destroy() {

			this.options.state.isDestroyed = true;
			return this._error('destroy');

		},

		// Set pause value to false
		pause: function infscr_pause() {
			this._pausing('pause');
		},

		// Set pause value to false
		resume: function infscr_resume() {
			this._pausing('resume');
		},

		// Retrieve next set of content items
		retrieve: function infscr_retrieve(pageNum) {

			var instance = this,
				opts = instance.options,
				path = opts.path,
				box, frag, desturl, method, condition,
				pageNum = pageNum || null,
				getPage = (!!pageNum) ? pageNum : opts.state.currPage;
			beginAjax = function infscr_ajax(opts) {

				// increment the URL bit. e.g. /page/3/
				opts.state.currPage++;

				instance._debug('heading into ajax', path);

				// if we're dealing with a table we can't use DIVs
				box = $(opts.contentSelector).is('table') ? $('<tbody/>') : $('<div/>');

				desturl = path.join(opts.state.currPage);

				method = (opts.dataType == 'html' || opts.dataType == 'json') ? opts.dataType : 'html+callback';
				if (opts.appendCallback && opts.dataType == 'html') method += '+callback'

				switch (method) {

					case 'html+callback':

						instance._debug('Using HTML via .load() method');
						box.load(desturl + ' ' + opts.itemSelector, null, function infscr_ajax_callback(responseText) {
							instance._loadcallback(box, responseText);
						});

						break;

					case 'html':
					case 'json':

						instance._debug('Using ' + (method.toUpperCase()) + ' via $.ajax() method');
						$.ajax({
							// params
							url: desturl,
							dataType: opts.dataType,
							complete: function infscr_ajax_callback(jqXHR, textStatus) {
								condition = (typeof (jqXHR.isResolved) !== 'undefined') ? (jqXHR.isResolved()) : (textStatus === "success" || textStatus === "notmodified");
								(condition) ? instance._loadcallback(box, jqXHR.responseText) : instance._error('end');
							}
						});

						break;
				}
			};

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['retrieve_' + opts.behavior] !== undefined) {
				this['retrieve_' + opts.behavior].call(this, pageNum);
				return;
			}


			// for manual triggers, if destroyed, get out of here
			if (opts.state.isDestroyed) {
				this._debug('Instance is destroyed');
				return false;
			};

			// we dont want to fire the ajax multiple times
			opts.state.isDuringAjax = true;

			opts.loading.start.call($(opts.contentSelector)[0], opts);

		},

		// Check to see next page is needed
		scroll: function infscr_scroll() {

			var opts = this.options,
				state = opts.state;

			// if behavior is defined and this function is extended, call that instead of default
			if (!!opts.behavior && this['scroll_' + opts.behavior] !== undefined) {
				this['scroll_' + opts.behavior].call(this);
				return;
			}

			if (state.isDuringAjax || state.isInvalidPage || state.isDone || state.isDestroyed || state.isPaused) return;

			if (!this._nearbottom()) return;

			this.retrieve();

		},

		// Toggle pause value
		toggle: function infscr_toggle() {
			this._pausing();
		},

		// Unbind from scroll
		unbind: function infscr_unbind() {
			this._binding('unbind');
		},

		// update options
		update: function infscr_options(key) {
			if ($.isPlainObject(key)) {
				this.options = $.extend(true, this.options, key);
			}
		}

	}


	/*	
	----------------------------
	Infinite Scroll function
	----------------------------
	
	Borrowed logic from the following...
	
	jQuery UI
	- https://github.com/jquery/jquery-ui/blob/master/ui/jquery.ui.widget.js
	
	jCarousel
	- https://github.com/jsor/jcarousel/blob/master/lib/jquery.jcarousel.js
	
	Masonry
	- https://github.com/desandro/masonry/blob/master/jquery.masonry.js		
	
	*/

	$.fn.infinitescroll = function infscr_init(options, callback) {


		var thisCall = typeof options;

		switch (thisCall) {

			// method  
			case 'string':

				var args = Array.prototype.slice.call(arguments, 1);

				this.each(function () {

					var instance = $.data(this, 'infinitescroll');

					if (!instance) {
						// not setup yet
						// return $.error('Method ' + options + ' cannot be called until Infinite Scroll is setup');
						return false;
					}
					if (!$.isFunction(instance[options]) || options.charAt(0) === "_") {
						// return $.error('No such method ' + options + ' for Infinite Scroll');
						return false;
					}

					// no errors!
					instance[options].apply(instance, args);

				});

				break;

			// creation  
			case 'object':

				this.each(function () {

					var instance = $.data(this, 'infinitescroll');

					if (instance) {

						// update options of current instance
						instance.update(options);

					} else {

						// initialize new instance
						$.data(this, 'infinitescroll', new $.infinitescroll(options, callback, this));

					}

				});

				break;

		}

		return this;

	};



	/* 
	* smartscroll: debounced scroll event for jQuery *
	* https://github.com/lukeshumard/smartscroll
	* Based on smartresize by @louis_remi: https://github.com/lrbabe/jquery.smartresize.js *
	* Copyright 2011 Louis-Remi & Luke Shumard * Licensed under the MIT license. *
	*/

	var event = $.event,
		scrollTimeout;

	event.special.smartscroll = {
		setup: function () {
			$(this).bind("scroll", event.special.smartscroll.handler);
		},
		teardown: function () {
			$(this).unbind("scroll", event.special.smartscroll.handler);
		},
		handler: function (event, execAsap) {
			// Save the context
			var context = this,
			  args = arguments;

			// set correct event type
			event.type = "smartscroll";

			if (scrollTimeout) { clearTimeout(scrollTimeout); }
			scrollTimeout = setTimeout(function () {
				$.event.handle.apply(context, args);
			}, execAsap === "execAsap" ? 0 : 100);
		}
	};

	$.fn.smartscroll = function (fn) {
		return fn ? this.bind("smartscroll", fn) : this.trigger("smartscroll", ["execAsap"]);
	};


})(window, jQuery);