var net = new Object();

net.READY_STATE_UNINITIALIZED = 0;
net.READY_STATE_LOADING = 1;
net.READY_STATE_LOADED = 2;
net.READY_STATE_INTERACTIVE = 3;
net.READY_STATE_COMPLETE = 4;
net.ContentLoader = function(url, onload, onerror, method, params, contentType) {
	this.req = null;
	net.currentLoader = this;
	this.onload = onload;
	this.onerror = (onerror) ? onerror : this.defaultError;
	this.loadXMLDoc(url, method, params, contentType);
}

net.ContentLoader.prototype.loadXMLDoc = function(url, method, params, contentType) {
	if (!method) {
		method = "GET";
	}
	if (!contentType && method == "POST") {
		contentType = 'application/x-www-form-urlencoded; charset=utf-8';
	}
	if (window.XMLHttpRequest) {
		this.req = new XMLHttpRequest();
	} else if (window.ActiveXObject) {
		this.req = new ActiveXObject("Microsoft.XMLHTTP");
	}
	if (this.req) {
		try {
			var loader = this;
			this.req.onreadystatechange = function() {
				net.ContentLoader.onReadyState.call(loader);
			}
			this.req.open(method, url, true);
			if (contentType) {
				this.req.setRequestHeader('Content-Type', contentType);
			}
			this.req.send(params);
		} catch (err) {
			this.onerror.call(this);
		}
	}
}


net.ContentLoader.onReadyState = function() {
	var req = this.req;
	var ready = req.readyState;
	if (ready == net.READY_STATE_COMPLETE) {
		var httpStatus = req.status;
		if (httpStatus == 200 || httpStatus == 0) {
			this.onload.call(this);
		} else {
			this.onerror.call(this);
		}
	}
}

net.ContentLoader.prototype.defaultError = function() {
	alert("error fetching data!"
			+ "\n\nreadyState:" + this.req.readyState
			+ "\nstatus: " + this.req.status
			+ "\nheaders: " + this.req.getAllResponseHeaders());
}
net.cmdQueues = new Array();
net.CommandQueue = function(id, url, onUpdate, freq) {
	this.id = id;
	net.cmdQueues[id] = this;
	this.url = url;
	this.queued = new Array();
	this.sent = new Array();
	this.onUpdate = onUpdate;
	if (freq) {
		this.repeat(freq);
	}
	this.lastUpdateTime = 0;
}
net.CommandQueue.STATUS_QUEUED = -1;
net.CommandQueue.STATE_UNINITIALIZED = net.READY_STATE_UNINITIALIZED;
net.CommandQueue.STATE_LOADING = net.READY_STATE_LOADING;
net.CommandQueue.STATE_LOADED = net.READY_STATE_LOADED;
net.CommandQueue.STATE_INTERACTIVE = net.READY_STATE_INTERACTIVE;
net.CommandQueue.STATE_COMPLETE = net.READY_STATE_COMPLETE;
net.CommandQueue.STATE_PROCESSED = 5;
net.CommandQueue.PRIORITY_NORMAL = 0;
net.CommandQueue.PRIORITY_IMMEDIATE = 1;
net.CommandQueue.prototype.addCommand = function(command) {
	if (this.isCommand(command)) {
		this.queue.append(command, true);
		if (command.priority == net.CommandQueue.PRIORITY_IMMEDIATE) {
			this.fireRequest();
		}
	}
}
net.CommandQueue.prototype.fireRequest = function() {
	if (!this.onUpdate && this.queued.length == 0) {
		return;
	}
	var data = "lastUpdate=" + this.lastUpdateTime + "&data=";
	for (var i = 0; i < this.queued.length; i++) {
		var cmd = this.queued[i];
		if (this.isCommand(cmd)) {
			data += cmd.toRequestString();
			this.sent[cmd.id] = cmd;
		}
	}
	this.queued = new Array();
	this.loader = new net.ContentLoader(
			this.url,
			net.CommandQueue.onload,
			net.CommandQueue.onerror,
			"POST", data
			);
}

net.CommandQueue.prototype.isCommand = function(obj) {
	return (
			obj.implementsProp("id")
					&& obj.implementsProp("priority")
					&& obj.implementsFunc("toRequestString")
					&& obj.implementsFunc("parseResponse")
			);
}

net.CommandQueue.onload = function() {
	var xmlDoc = this.req.responseXML;
	var elDocRoot = xmlDoc.getElementsByTagName("responses")[0];
	var lastUpdate = elDocRoot.attributes.getNamedItem("updateTime");
	if (parseInt(lastUpdate) > this.lastUpdateTime) {
		this.lastUpdateTime = lastUpdate;
	}
	if (elDocRoot) {
		for (i = 0; i < elDocRoot.childNodes.length; i++) {
			elChild = elDocRoot.childNodes[i];
			if (elChild.nodeType == 1) {
				if (elChild.tagName == "command") {
					var attrs = elChild.attributes;
					var id = attrs.getNamedItem("id").value;
					var command = net.commandQueue.sent[id];
					if (command) {
						command.parseResponse(elChild);
					}
				} else if (elChild.tagName == "update") {
					if (this.implementsFunc("onUpdate")) {
						this.onUpdate.call(this, elChild);
					}
				}
			}
		}
	}
}

net.CommandQueue.onerror = function() {
	alert("problem sending the data to the server");
}

net.CommandQueue.prototype.repeat = function(freq) {
	this.unrepeat();
	if (freq > 0) {
		this.freq = freq;
		var cmd = "net.cmdQueues[" + this.id + "].fireRequest()";
		this.repeater = setInterval(cmd, freq * 1000);
	}
}
net.CommandQueue.prototype.unrepeat = function() {
	if (this.repeater) {
		clearInterval(this.repeater);
	}
	this.repeater = null;
}