//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.childNodes[0] == 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) {
			if (tmpElement.childNodes[0] != 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]);
	
	//if (this.description) this.description = this.description.replace(/(<([^>]+)>)/ig,"");
	//if (this.title) this.title = this.title.replace(/(<([^>]+)>)/ig,"");

}

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

//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", "language", "copyright", "managingEditor", "webMaster", "pubDate", "lastBuildDate", "generator", "docs", "ttl", "rating");
	var tmpElement = null;
	for (var i=0; i<properties.length; i++)
	{
		tmpElement = chanElement.getElementsByTagName(properties[i])[0];
		if (tmpElement!= null)
			if (tmpElement.childNodes[0]) {
				eval("this."+properties[i]+"=tmpElement.childNodes[0].nodeValue");
			}
	}

	if (this.description) this.description = this.description.replace(/(<([^>]+)>)/ig,"");
	if (this.title) this.title = this.title.replace(/(<([^>]+)>)/ig,"");
	if (!(this.description)) this.description = "";
	if (!(this.copyright)) this.copyright = "";
	
	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(rssurl)
{
	//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",rssurl,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 imageTag = "<img class='chan_image'";
	var startItemTag = "<div class='item'>";
	var startTitle = "<div class='item_title'>";
	var startLink = "<div class='item_link'>";
	var startDescription = "<div class='item_description'>";
	var startPubDate = "<div class='item_date'>";
	var endTag = "</div>";

	//populate channel data
	var properties = new Array("title","link","description","copyright");
	for (var i=0; i<properties.length; i++)
	{
		eval("document.getElementById('chan_"+properties[i]+"').innerHTML = ''");
		curProp = eval("RSS."+properties[i]);
		if (curProp != null)
			if (properties[i] == "link") {
				curProp = "<a href='"+curProp+"'>"+curProp+"</a>";
			} 
			eval("document.getElementById('chan_"+properties[i]+"').innerHTML = curProp");
	}

	//show the image
	document.getElementById("chan_image_link").innerHTML = "";
	if (RSS.image.src != null)
	{
		document.getElementById("chan_image_link").href = RSS.image.link;
		document.getElementById("chan_image_link").innerHTML = imageTag
			+" alt='"+RSS.image.description
			+"' width='"+RSS.image.width
			+"' height='"+RSS.image.height
			+"' src='"+RSS.image.url
			+"' "+"/>";
	}

	//populate the items
	document.getElementById("chan_items").innerHTML = "";
	for (var i=0; i<3; i++)
	{
		if (RSS.items[i].pubDate != null) {
			var item_date = RSS.items[i].pubDate;
			if (item_date.indexOf("+") > 1) {
				item_date = item_date.substring(0,item_date.lastIndexOf("+") - 1);
			} else {
				item_date = item_date.substring(0,item_date.lastIndexOf("-") - 1);
			}
			var item_time = item_date.substring(item_date.lastIndexOf(" ")+1);
			item_time = item_time.substring(0,item_time.lastIndexOf(":"));
			item_date = item_date.substring(0,item_date.lastIndexOf(" "));
			if (item_time.substring(0,2) == 0) {
				item_time = "12" + item_time.substring(2) + " AM";
			} else if (item_time.substring(0,2) > 12) {
				var item_time_hour = item_time.substring(0,2) - 12;
				item_time = item_time_hour + item_time.substring(2) + " PM";
			} else {
				item_time = item_time + " AM";
			}
		}
		
		item_html = "";
		item_html += (RSS.items[i].title == null || RSS.items[i].link == null) ? "" : "<h1>" + RSS.items[i].title + "</h1>";
		item_html += (RSS.items[i].description == null) ? "" :  RSS.items[i].description;
		item_html += "<div class=\"border\"></div>";
		document.getElementById("chan_items").innerHTML += item_html;
	}

	//we're done
	//document.getElementById("chan").style.visibility = "visible";
	return true;
}

var xhr;