dojo.provide("dojox.analytics._base");

dojox.analytics = function(){
	//where we store data until we're ready to send it off.

	//the data queue;
	this._data = [] ;

	//id of messages for this session/page
	this._id=1;

	//some default values
	this.sendInterval=dojo.config["sendInterval"] || 5000;
	this.inTransitRetry=dojo.config["inTransitRetry"] || 200;
	this.dataUrl=dojo.config["analyticsUrl"] || dojo.moduleUrl("dojox.analytics.logger", "dojoxAnalytics.php");
	this.sendMethod = dojo.config["sendMethod"] || "xhrPost";
	if (dojo.isIE){
		this.maxRequestSize = 2000;
	}else{
		this.maxRequestSize = dojo.config["maxRequestSize"] || 4000;	
	}

	//while we can go ahead and being logging as soon as this constructor is completed
	//we're not going to schedule pushing data to the server until after the page
	//has completed loading
	dojo.addOnLoad(this, "schedulePusher");
	dojo.addOnUnload(this, "pushData", true);
};

dojo.extend(dojox.analytics, {
	schedulePusher: function(interval){
		// summary:
		//	schedule the data pushing routines to happen in interval ms
		setTimeout(dojo.hitch(this, "checkData"), interval||this.sendInterval); 
	},

	addData: function(dataType, data){
		// summary:
		//	add data to the queue. Will be pusshed to the server on the next
		//	data push

		if (arguments.length>2){
			var d = [];
			for(var i=1;i<arguments.length;i++){
				d.push(arguments[i]);
			}
			data = d;
		}

		this._data.push({plugin: dataType, data: data});
	},

	checkData: function(){
		// summary
		if (this._inTransit){
			this.schedulePusher(this.inTransitRetry);
			return;
		}

		if (this.pushData()){return}
		this.schedulePusher();
	},

	pushData: function(){
		// summary
		//	pushes data to the server if any exists.  If a push is done, return
		//	the deferred after hooking up completion callbacks.  If there is no data
		//	to be pushed, return false;
		if (this._data.length>0){
			//clear the queue
			this._inTransit=this._data;
			this._data=[];
			var def;
			switch(this.sendMethod){
				case "script":
					def = dojo.io.script.get({url: this.getQueryPacket(), preventCache: 1, callbackParamName: "callback"});
					break;
				case "xhrPost":
				default:
					def = dojo.xhrPost({url:this.dataUrl, content: {id: this._id++, data: dojo.toJson(this._inTransit)}});
					break;
			}
			def.addCallback(this, "onPushComplete");
			return def;
		}
		return false;
	},

	getQueryPacket: function(){
		while(true){
			var content = {id: this._id++, data: dojo.toJson(this._inTransit)};

			//FIXME would like a much better way to get the query down to lenght
			var query = this.dataUrl + '?' + dojo.objectToQuery(content);
			if (query.length>this.maxRequestSize){
				this._data.unshift(this._inTransit.pop());	
				this._split=1;
			}else{
				return query;
			}	
		}
	},

	onPushComplete: function(results){
		// summary
		//	if our data push was successfully, remove the _inTransit data and schedule the next
		//	parser run.
		if (this._inTransit){
			delete this._inTransit;
		}

		if (this._data.length>0){
			this.schedulePusher(this.inTransitRetry);
		} else {
			this.schedulePusher();
		}
	}
});

//create the analytics  singleton
dojox.analytics = new dojox.analytics();
