//OBJECTS

//objects inside the RSS2Item object
function RSS2Enclosure(encElement)
{
	if (encElement == null)
	{
		this.url = null;
		this.length = null;
		this.type = null;
	}
	else
	{
		this.url = encElement.getAttribute("url");
		this.length = encElement.getAttribute("length");
		this.type = encElement.getAttribute("type");
	}
}

function RSS2Guid(guidElement)
{
	if (guidElement == null)
	{
		this.isPermaLink = null;
		this.value = null;
	}
	else
	{
		this.isPermaLink = guidElement.getAttribute("isPermaLink");
		this.value = guidElement.childNodes[0].nodeValue;
	}
}

function RSS2Source(souElement)
{
	if (souElement == null)
	{
		this.url = null;
		this.value = null;
	}
	else
	{
		this.url = souElement.getAttribute("url");
		this.value = souElement.childNodes[0].nodeValue;
	}
}

//object containing the RSS 2.0 item
function RSS2Item(itemxml)
{
	//required
	this.title;
	this.link;
	this.description;

	//optional vars
	this.author;
	this.comments;
	this.pubDate;

	//optional objects
	this.category;
	this.enclosure;
	this.guid;
	this.source;

	var properties = new Array("title", "link", "description", "author", "comments", "pubDate");
	var tmpElement = null;
	for (var i=0; i<properties.length; i++)
	{
		tmpElement = itemxml.getElementsByTagName(properties[i])[0];
		if (tmpElement != null)
			eval("this."+properties[i]+"=tmpElement.childNodes[0].nodeValue");
	}

	this.category = new RSS2Category(itemxml.getElementsByTagName("category")[0]);
	this.enclosure = new RSS2Enclosure(itemxml.getElementsByTagName("enclosure")[0]);
	this.guid = new RSS2Guid(itemxml.getElementsByTagName("guid")[0]);
	this.source = new RSS2Source(itemxml.getElementsByTagName("source")[0]);
}

//objects inside the RSS2Channel object
function RSS2Category(catElement)
{
	if (catElement == null)
	{
		this.domain = null;
		this.value = null;
	}
	else
	{
		this.domain = catElement.getAttribute("domain");
		this.value = catElement.childNodes[0].nodeValue;
	}
}

//object containing RSS image tag info
function RSS2Image(imgElement)
{
	if (imgElement == null)
	{
	this.url = null;
	this.link = null;
	this.width = null;
	this.height = null;
	this.description = null;
	}
	else
	{
		imgAttribs = new Array("url","title","link","width","height","description");
		for (var i=0; i<imgAttribs.length; i++)
			if (imgElement.getAttribute(imgAttribs[i]) != null)
				eval("this."+imgAttribs[i]+"=imgElement.getAttribute("+imgAttribs[i]+")");
	}
}

//object containing the parsed RSS 2.0 channel
function RSS2Channel(rssxml)
{
	//required
	this.title;
	this.link;
	this.description;

	//array of RSS2Item objects
	this.items = new Array();

	//optional vars
	this.language;
	this.copyright;
	this.managingEditor;
	this.webMaster;
	this.pubDate;
	this.lastBuildDate;
	this.generator;
	this.docs;
	this.ttl;
	this.rating;

	//optional objects
	this.category;
	this.image;

	var chanElement = rssxml.getElementsByTagName("channel")[0];
	var itemElements = rssxml.getElementsByTagName("item");

	for (var i=0; i<itemElements.length; i++)
	{
		Item = new RSS2Item(itemElements[i]);
		this.items.push(Item);
		//chanElement.removeChild(itemElements[i]);
	}

	var properties = new Array("title", "link", "description", "pubDate");
	var tmpElement = null;
	for (var i=0; i<properties.length; i++)
	{
		tmpElement = chanElement.getElementsByTagName(properties[i])[0];
		if (tmpElement!= null)
			eval("this."+properties[i]+"=tmpElement.childNodes[0].nodeValue");
	}

	this.category = new RSS2Category(chanElement.getElementsByTagName("category")[0]);
	this.image = new RSS2Image(chanElement.getElementsByTagName("image")[0]);
}

//PROCESSES

//uses xmlhttpreq to get the raw rss xml
function getRSS(rssFile)
{
	//call the right constructor for the browser being used
	if (window.ActiveXObject){
		xhr = new ActiveXObject("Microsoft.XMLHTTP");
	}
	else if (window.XMLHttpRequest)
		xhr = new XMLHttpRequest();
	else
		alert("not supported");

	//prepare the xmlhttprequest object
	xhr.open("GET",rssFile,true);
	xhr.setRequestHeader("Cache-Control", "no-cache");
	xhr.setRequestHeader("Pragma", "no-cache");
	xhr.onreadystatechange = function() {
		if (xhr.readyState == 4)
		{
			if (xhr.status == 200)
			{
				if (xhr.responseText != null)
					processRSS(xhr.responseXML);
				else
				{
					alert("Failed to receive RSS file from the server - file not found.");
					return false;
				}
			}
			else
				alert("Error code " + xhr.status + " received: " + xhr.statusText);
		}
	}

	//send the request
	xhr.send(null);
}

//processes the received rss xml
function processRSS(rssxml)
{
	RSS = new RSS2Channel(rssxml);
	showRSS(RSS);
}

//shows the RSS content in the browser
function showRSS(RSS)
{
	//default values for html tags used
	var title1Text = "<h1>What's New<br /><font size='2'>Plug-In Partners News</font></h1>";
	var title2Text = "<h1>News Items</h1>";
	var startItem = "<h2><strong>";
	var linkStart = "<a href='";
	var linkFinish = "' target='_blank'>";
	var closeLink = "</a>";
	var closeTitle = "</strong></h2>";
	var startParagraph = "<p>";
	var endLine = "</p><br />";
	var linkCaret = "&nbsp;&raquo;";

	var item_html = "";
	var itemMatched = -1;

	//get the article that was selected in the link if it exists
	var selector = window.location.search.substring(1);  //item selector
	if (selector != ""){
		for (var j=0; j<RSS.items.length; j++){
			var getLink = RSS.items[j].pubDate;
			getLink = escape(getLink);

			if((selector == getLink)&&(RSS.items[j].title != null)){
				//item_html += title1Text;
				//startItem += ;
				item_html += (RSS.items[j].link == null) ? "" : linkStart + RSS.items[j].link + linkFinish;
				item_html += (RSS.items[j].title == null) ? "" : startItem + RSS.items[j].title;
				item_html += (RSS.items[j].link == null) ? "" : linkCaret;
				item_html += (RSS.items[j].title == null) ? "" : closeTitle;
				item_html += (RSS.items[j].link == null) ? "" : closeLink;
				item_html += (RSS.items[j].description == null) ? "" : startParagraph + RSS.items[j].description +
						endLine;
				itemMatched = j;
				j = RSS.items.length;
			} // end if condition

		}// end of for loop to check first three items for link reference
	}// end of selector conditional 
	
	item_html += title2Text; 	// add the separating text. If no article was selected 
												// from a link, then this will simply be the header

	//populate the other items
	for (var i=0; i<RSS.items.length; i++){
		if (i!=itemMatched){
				item_html += (RSS.items[i].link == null) ? "" : linkStart + RSS.items[i].link + linkFinish;
				item_html += (RSS.items[i].title == null) ? "" : startItem + RSS.items[i].title;
				item_html += (RSS.items[i].link == null) ? "" : linkCaret;
				item_html += (RSS.items[i].title == null) ? "" : closeTitle;
				item_html += (RSS.items[i].link == null) ? "" : closeLink;
				item_html += (RSS.items[i].description == null) ? "" : startParagraph + RSS.items[i].description +
						endLine;
		}
	}
	
	document.getElementById('RSSContentPage').innerHTML = item_html;
	//we're done

	return true;
}

var xhr;