/* Lightweight ad-serving code */
function $(id) { return document.getElementById(id); }

function getAds(type, count) {
    inventory[type].sort(function() {return Math.random() - Math.random()});
    if (!count || count==1)
        return inventory[type][0];
    inventory[type].length = count;
    return inventory[type];
}

function writeAd(ad,node) {
    /*var i = Math.floor(Math.random() * inventory[type].length);
    var ad = inventory[type][i];*/
    var url;
    if (ad.adlink.indexOf('http')==0)
        url = 'adverts/tracker.php?url=' + encodeURIComponent(ad.adlink);
    else 
        url = ad.adlink;
    node.innerHTML = '<a href="' + url + '"><img src="' + ad.path + '" alt="' + ad.alt + '"/></a>';
}

window.onload = function() {
    var banner = $('banner');
    if (banner) {
        writeAd(getAds('banners'), banner);
    }
    
    var sidebar = $('tower');
    if (sidebar) {
        writeAd(getAds('sidebar'), sidebar);
    }
    
    var house = $('housead-1');
    if (house) {
        var ads = getAds('house', 4);
        for (var i=0; i < 4; i++) {
            var n = $('housead-' + (i+1));
            if (n)
                writeAd(ads[i], n);
        }
    }

}