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

// 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/

 
;(function($) {

	$.fn.infinitescroll = function(options, callback) {
		var opts    = $.extend({}, $.fn.infinitescroll.defaults, options);
		var props   = $.fn.infinitescroll; // shorthand
		callback    = callback || function(){};
		
		// get the relative URL - everything past the domain name.
		var relurl        = /(.*?\/\/).*?(\/.*)/;
		var path          = $(opts.nextSelector).attr('href');
		path          = path.match(relurl) ? path.match(relurl)[2] : path; 
		
		$.fn.infinitescroll.loadingMsg = $('<div id="infscr-loading" style="position: fixed; background-color: #fff; -moz-border-radius:3px; -khtml-border-radius: 3px; -webkit-border-radius:3px; padding: 6px; right: 50px; bottom: 50px; text-align: left;"><img style="float:none;" alt="Loading..." src="'+opts.loadingImg+'" /><br /><span>'+opts.loadingText+'</span></div>');
		
		//distance from nav links to bottom of page
		props.scrollDelta = $.fn.infinitescroll.scrollDelta  = $(document).height() - $(opts.navSelector).offset().top; 
		
		(new Image()).src = opts.loadingImg; // preload the image.
		
		if (path.split('2').length == 2) { // there is a 2 in the next url, e.g. /page/2/
			path = path.split('2');
		} else {
			opts.debug && console && console.log('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.');
			props.isInvalidPage = true;  //prevent it from running on this page.
		}
		
		$(document).ajaxError(function(e,xhr,opt) {
			
			props.isDone = true;
			
			if (props.isDone) { // if we've hit the last page...
				props.loadingMsg.find('img').hide().parent().find('span').html(opts.donetext).animate({opacity: 1},2000).fadeOut('normal');
			}
			
			opts.debug && console && console.log('Page not found. Self-destructing...');
			
			if (xhr.status == 404){ props.isDone = true; } // die if we're out of pages.
			
		});
		
		$(window).scroll(function() {infscrSetup(path, opts, props, callback);}); // hook up the function to the window scroll event.
		
		infscrSetup(path, opts, props, callback); // check short pages to see if they should go
		
		return this;
	}  
    
	
	
	function isNearBottom(opts,props)
	{
		//alert($(document).height() + ',' + $(document).scrollTop()+ ',' + $(window).height()+ ',' + props.scrollDelta);
		//return (  $(document).height() - $(document).scrollTop() - $(window).height() - 500 <  props.scrollDelta);
		return ($(document).height() - $(document).scrollTop() - $(window).height() - 200 <  0);
	}



	function infscrSetup(path, opts, props, callback)
	{
		if (props.isDuringAjax || props.isInvalidPage || props.isDone) return; 
  
     	// the math is: docheight - distancetotopofwindow - height of window < docheight - distance of nav element to the top. [go algebra!]
  		if (isNearBottom(opts,props)) { 
  		
			//offy = $('#allposts').offset().top;
			//offx = $('#allposts').offset().left;
			//arrange();
  		  
  			props.isDuringAjax = true; // we dont want to fire the ajax multiple times
  			props.loadingMsg.appendTo(opts.contentSelector).show();
  			$(opts.navSelector).hide(); // take out the previous/next links
  			props.currPage++;
  			
  			// if we're dealing with a table we can't use DIVs
  			var box = $(opts.contentSelector).is('table') ? $('<tbody/>') : $('<div/>');
  			box
			.attr('id', 'infscr-page-' + props.currPage)
			.attr('class', 'infscr-pages')
			.appendTo(opts.contentSelector)
			.load(path.join(props.currPage) + ' ' + opts.itemSelector, null, function(){
																																																 				if (props.isDone) { // if we've hit the last page...
  					
					props.loadingMsg
					.find('img')
					.hide()
					.parent()
					.find('span')
					.html(opts.donetext)
					.animate({opacity: 1}, 2000)
					.fadeOut('normal');
					
  		    	} else {
					
					props.loadingMsg.fadeOut('fast'); // currently makes the <em>'d text ugly in IE6
					
					pageTracker._trackPageview(path.join(props.currPage));//Google Analytics
				
					if (opts.animate) { // smooth scroll to ease in the new content
						var scrollTo = jQuery(window).scrollTop() + jQuery('#infscr-loading').height() + opts.extraScrollPx + 'px';
						jQuery('html,body').animate({scrollTop: scrollTo}, 800,function(){ props.isDuringAjax = false; });
					}
				
					props.currDOMChunk = $('#infscr-page-' + props.currPage)[0]; // convenience for callback. ACTUAL DOM, not jQ obj.
					callback.call(props.currDOMChunk);
					if (!opts.animate) props.isDuringAjax = false; // once the call is done, we can allow it again.
					
				}
				
			});
		}
	}
  
$.extend($.fn.infinitescroll, { // more configuration set in init()
        defaults      : {
                          debug           : false,
                          nextSelector    : "div.navigation a:first",
                          loadingImg      : "http://www.infinite-scroll.com/loading.gif",
                          loadingText     : "",
                          donetext        : "<em>Congratulations, you've reached the end of the internet.</em>",
                          navSelector     : "div.navigation",
                          contentSelector : this,           // not really a selector. :) it's whatever the method was called on..
                          extraScrollPx   : 100,
                          itemSelector    : "div.post",
                          animate         : false
                        }, 
        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);