// Infinite Scroll jQuery plugin
// copyright Paul Irish
// version 1.1.2008.09.25

// Modified by Chris Hill-Scott
// (stripped out bits I didn't need and made more readable)

// project home  : http://www.infinite-scroll.com
// documentation : http://www.infinite-scroll.com/infinite-scroll-jquery-plugin/

// dual license  : GPL : http://creativecommons.org/licenses/GPL/2.0/
//               : MIT : http://creativecommons.org/licenses/MIT/

// todo: add callback for the complete (404) state.
//       add preloading option.
//       fix with jorn's syntax improvements.

;(function($){

	$.fn.infinitescroll = function(options) {

		if (QUIS.isMobile) {

			return this;

		}

		var opts = $.extend({}, $.fn.infinitescroll.defaults, options),
			props = $.fn.infinitescroll, // shorthand
			path = $(opts.nextSelector).attr("href") || "invalid"; // get the relative URL - everything past the domain name

		if (null == path.match("page")) return this;

		path = path.split("page");
		props.currPage = (path[1].replace(/\//gi, "")) - 1;
		path = path[0] + "page/";

		// contentSelector is just the element you're calling the infinitescroll() method on.
		opts.contentSelector = opts.contentSelector || this;

		$.fn.infinitescroll.loadingMsg = $('<div id="infscr-loading" />');

		QUIS.$document
			.ajaxError(
				function(e,xhr,opt) {
					if (404 == xhr.status) {
						props.isDone = true; // die if we're out of pages
					}
				}
			);

		QUIS.$window
			.scroll(
				function() {
					infscrSetup(path,opts,props); // hook up the function to the window scroll event.
				}
			);

		// Behave nicely
		return this;

	}


	function isNearBottom() {

		var alltheway = QUIS.$document.height(),
			scrolling = QUIS.$window.scrollTop() + QUIS.$window.height() + 1200;

		return (scrolling > alltheway);

	}

	function infscrSetup(path,opts,props){

		if (props.isDuringAjax || props.isInvalidPage || props.isDone || !isNearBottom() || QUIS.isMobile) return;

		props.isDuringAjax = true; // we dont want to fire the ajax multiple times
		props.currPage++;

		props.loadingMsg
			.appendTo(opts.contentSelector)
			.show();

		var analyticsPath = path + props.currPage + "/?mode=AJAX",
			pageID = "infscr-page-" + props.currPage;

		path = path + props.currPage + "/"; // AJAX caching on the server side is currently broken

		$("<div/>")
			.attr("id", pageID)
			.attr("class","infscr-pages")
			.appendTo(opts.contentSelector)
			.load(
				path + " " + opts.itemSelector,
				null,
				function() {

					props.loadingMsg
						.delay(600)
						.fadeOut(
							"fast",
							function() {
								$(this)
									.remove();
							}
						);

					if (props.isDone) { // if we've hit the last page...

						$("#footer p:last")
							.html(opts.donetext)
							.fadeIn("slow");

					}

					opts.callback.apply(this, [analyticsPath, pageID]);
					props.isDuringAjax = false;

				}
			);

	}

	$.extend(
		$.fn.infinitescroll,
		{
			defaults: {
				debug: false,
				nextSelector: "",
				loadingText: "",
				donetext: "",
				navSelector: "",
				contentSelector: null,           // not really a selector. :) it's whatever the method was called on..
				itemSelector: "",
				callback: function(path) {},
				offset: 1200
			},
			currPage: 1,
			currDOMChunk: null,  // defined in setup()'s load()
			isDuringAjax: false,
			isInvalidPage: false,
			isDone: false  // for when it goes all the way through the archive.
		}
	);

})(jQuery);