//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];
        try {
            if (tmpElement != null)
                eval("this."+properties[i]+"=tmpElement.childNodes[0].nodeValue");
        } catch (exception) {
        }
    }

    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++)
            try {
                if (imgElement.getAttribute(imgAttribs[i]) != null)
                    eval("this."+imgAttribs[i]+"=imgElement.getAttribute("+imgAttribs[i]+")");
            } catch (exception) {
            }
    }
}

//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];
        try {
            if (tmpElement!= null)
                eval("this."+properties[i]+"=tmpElement.childNodes[0].nodeValue");
        } catch (exception) {
        }
    }

    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(linkLocation)
{
    //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",linkLocation,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) {
                    var doc = null;
                    // code for IE
                    if (window.ActiveXObject)
                    {
                      var doc=new ActiveXObject("Microsoft.XMLDOM");
                      doc.async="false";
                      doc.loadXML(xhr.responseText);
                    }
                    // code for Mozilla, Firefox, Opera, etc.
                    else
                    {
                      var parser=new DOMParser();
                      var doc=parser.parseFromString(xhr.responseText,"text/xml");
                    }
                    if (doc) {
                        processRSS(doc);
                    }
                    else
                    {
                        alert("Failed to parse RSS file from the server.");
                        return false;
                    }
                    //                    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 startItemTag = "<div id='item'>";
    var startDate = "<div id='item_date'>";
    var startTitle = "<div id='item_title'>";
    var startDescription = "<div id='item_description'>";
    var endTag = "</div>";

    //populate the items
    document.getElementById("chan_items").innerHTML = "";
    for (var i=0; i<RSS.items.length; i++)
    {
        item_html = startItemTag;
        item_html += (RSS.items[i].pubDate == null) ? "" : startDate + RSS.items[i].pubDate + endTag;
        item_html += (RSS.items[i].title == null) ? "" : startTitle + RSS.items[i].title + endTag;
        item_html += (RSS.items[i].description == null) ? "" : startDescription + RSS.items[i].description + endTag;
        item_html += (RSS.items[i].link == null) ? "" : "<a href='" + RSS.items[i].link + "'>More...</a>";
        item_html += endTag;
        document.getElementById("chan_items").innerHTML += item_html;
    }

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

//shows the RSS content in the browser
function showRSS_old(RSS)
{
    //default values for html tags used
    var imageTag = "<img id='chan_image'";
    var startItemTag = "<div id='item'>";
    var startTitle = "<div id='item_title'>";
    var startLink = "<div id='item_link'>";
    var startDescription = "<div id='item_description'>";
    var endTag = "</div>";

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

    //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<RSS.items.length; i++)
    {
        item_html = startItemTag+startTitle;
        item_html += (RSS.items[i].pubDate == null) ? "" : startTitle + RSS.items[i].pubDate + "&nbsp;";
        item_html += (RSS.items[i].title == null) ? "" : startTitle + RSS.items[i].title;
        item_html += endTag;
        item_html += (RSS.items[i].link == null) ? "" : startLink + RSS.items[i].link + endTag;
        item_html += (RSS.items[i].description == null) ? "" : startDescription + RSS.items[i].description + endTag;
        item_html += endTag;
        document.getElementById("chan_items").innerHTML += item_html;
    }

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


var xhr;