POSConnection.CONTROLLER_URL = "ajaxController";

function POSConnection(posName) {
  this.url = POSConnection.CONTROLLER_URL;
  this.setPOSName(posName);
}

POSConnection.prototype.send = function (inputXML, callback) {
  var pars = "posName=" + this.posName +
             "&inputDocument=" + encodeURI(inputXML);
  if(callback) {
    this.callServiceAsynchronously(pars, callback);
    return;
  } else {
    return this.callServiceSynchronously(pars);
  }
}

POSConnection.prototype.callServiceSynchronously = function (pars, inputXML) {
  var response = new Ajax.Request( this.url, { method: 'get', asynchronous:false, parameters: pars});
  return response.transport.responseXML;
}

POSConnection.prototype.callServiceAsynchronously = function (pars, callback) {
  var request = new Ajax.Request( this.url, { method: 'get', parameters: pars,
    onComplete: this.processSuccessfulCall.bind(this, callback),
    onFailure: this.processFailureCall.bind(this, callback)});
  return;
}

POSConnection.prototype.processSuccessfulCall = function(callback, response){
  callback(response.responseXML);
}

POSConnection.prototype.processFailureCall = function(callback, response){
  var errorXML = "<ERROR><ERROR_CODE>"
      + response.status
      + "</ERROR_CODE><ERROR_MESSAGE>ajax asynchronous failure statusText:"
      + response.statusText + "</ERROR_MESSAGE><STACK_TRACE/></ERROR>";

  var xmlDoc = this.parseDocument(errorXML);
  callback(xmlDoc);
}

POSConnection.prototype.setControllerURL = function(controllerURL){
  this.url = controllerURL;
}

POSConnection.prototype.setPOSName = function(posName){
  this.posName = posName;
}

POSConnection.prototype.verifyPOSNameExists = function(){
  if(!this.posName) {
    alert("Missing Mandatory Argument, \"POSName\". Request haulted.");
    return false;
  }
  return true;
}

POSConnection.prototype.parseDocument = function(xmlStr) {
	if(!xmlStr)
		xmlStr = "";

	if(document.all) {
		var xmlDoc = new ActiveXObject("Microsoft.FreeThreadedXMLDOM");
		xmlDoc.async = false;
		xmlDoc.loadXML(xmlStr);
		return xmlDoc;
	}

	var parser = new DOMParser();
	return parser.parseFromString(xmlStr, "text/xml");
}