var movideoAds = (function() {
	
	// find a Companion Ad with matching width and height
	// returns Companion Ad if matches
	// returns null if no matches
	function findCompanionAd(companionAds, width, height) 
	{
		for (var i in companionAds) 
		{
			var companionAd = companionAds[i];
			if (companionAd.width == width && companionAd.height == height) 
			{
				return companionAd;
			}
		}
		return null;
	}
	
	function createIFrameString(width, height, src) {
		var f = '<iframe ' 
			+ 'height="' + height + '" '
			+ 'width="' + width + '" ' 
			+ 'src="' + src + '" '
			+ 'scrolling="no" frameborder="0" vspace="0" marginwidth="0" marginheight="0" allowtransparency="yes"></iframe>'
		return f;
	}
	
	// 
	var generateedElementPrefix = "movideoAdsElement";
	var nextGeneratedId = 0;
	
	var defaultResourceHandlers = {
		// for html resources, replace the innerHTML with the resource. 
		// NOTE does not support <script> elements in the HTML resource.
		// 
		'html': function(companionAd, element) 
		{
			// when the companion resource starts with http:// then treat it as the src for an iframe element
			var url = companionAd.resource;
			var timestamp = new Date().getTime();
			url = url.replace(/\{timestamp\}/g, timestamp);

			// determine if resource is a URL for an iframe or plain html
			var isUrlResource = /^http:\/\//;
			if (isUrlResource.test(url))
			{
				element.innerHTML = createIFrameString(companionAd.width, companionAd.height, url);
			}
			else
			{
				element.innerHTML = url;
			}
		},
		
		// for iframe resources, simply change the IFrameElement.src to point to the new URL.
		// 
		'iframe': function(companionAd, element) 
		{
			var url = companionAd.resource;
			var timestamp = new Date().getTime();
			url = url.replace(/\{timestamp\}/g, timestamp);
			element.innerHTML = createIFrameString(companionAd.width, companionAd.height, url);
		},
		
		// for static resources, create HTML to wrap the resource, and inject to DOM. 
		// 
		'static': function(companionAd, element) 
		{
			// handle images resource by creating an <a> link with an <img />
			// matches creativeTypes such as: image/jpeg, image/gif
			// 
			if (companionAd.creativeType.indexOf('image') == 0) {
				var html 
					= '<a href="' + companionAd.clickThroughUrl + '" target="_blank">' 
					+ '<img border="0" src="' + companionAd.resource 
					+ '" width="' + companionAd.width 
					+ '" height="' + companionAd.height
					+ '" />'
					+ '</a>';
				
				element.innerHTML = html;
			}
			// handles SWFs by embedding in the ad container
			//
			else if (companionAd.creativeType == 'application/x-shockwave-flash') 
			{
				element.innerHTML = "";  
				var generatedElementId = (generateedElementPrefix + (nextGeneratedId++));
				var adElement = document.createElement("div");
				adElement.id = generatedElementId;
				element.appendChild(adElement);
				// some ads use clickTAG, and some use clickTag so we pass in both. 
				swfobject.embedSWF(companionAd.resource + '?clickTAG=' + companionAd.clickThroughUrl + "&clickTag=" + companionAd.clickThroughUrl, generatedElementId, companionAd.width, companionAd.height, '9.0.0');
			}
		}
	};
	
	return {
		adSlots: [],
    	          
    	adResourceHandlers: defaultResourceHandlers,
		
		updateAds: function (advertData) {
			for (var i in movideoAds.adSlots) {
				var adSlot = movideoAds.adSlots[i];
				if (adSlot) {
					var adElement = document.getElementById(adSlot.id);
					if (adElement) {
						var companionAd = findCompanionAd(advertData.companionAds, adSlot.width, adSlot.height);
						if (companionAd) {
							var resourceHandler = movideoAds.adResourceHandlers[companionAd.resourceType];
							if (resourceHandler) {
								resourceHandler(companionAd, adElement);
							}                                                
						}
					}
					
					if (adSlot.onChanged != null) {
						adSlot.onChanged();
					}
				}
			}
		},
		
		findCompanionAd: function(companionAds, width, height) {
			return findCompanionAd(companionAds, width, height);
		}
	}
})();