// (c) 2010 Jeff Mesnil -- http://jmesnil.net/
// stilts-stomp-client.js 0.1.24

(function(window) {

	var Stomp = {};

	Stomp.Headers = {
		HOST : 'host',
		CONTENT_LENGTH : 'content-length',
		CONTENT_TYPE : 'content-type',
		ACCEPT_VERSION : 'accept-version',
		VERSION : 'version'
	};

	Stomp.Versions = { 
		VERSION_1_0 : "1.0", 
		VERSION_1_1 : "1.1",
		
		supportedVersions : function() {
			return "1.0,1.1";
		}
	};
	
	Stomp.frame = function(command, headers, body) {
		return {
			command : command,
			headers : headers,
			body : body,
			toString : function() {
				var out = command + '\n';
				if (headers) {
					for (header in headers) {
						if (headers.hasOwnProperty(header)) {
							out = out + header + ':' + headers[header] + '\n';
						}
					}
				}
				if (body) {
					out = out + 'content-length:' + body.length + '\n';
				}
				out = out + '\n';
				if (body) {
					out = out + body;
				}
				return out;
			}
		}
	};

	trim = function(str) {
		return ("" + str).replace(/^\s+/g, '').replace(/\s+$/g, '');
	};

	Stomp.unmarshal = function(data) {
	    debug( "unmarshal: " + data );
		var divider     = data.search(/\n\n/);
		var headerLines = data.substring(0, divider).split('\n');
		var command     = headerLines.shift(), headers = {}, body = '';
		
		debug( headerLines );

		// Parse headers
		var line = idx = null;
		for ( var i = 0; i < headerLines.length; i++) {
			line = '' + headerLines[i];
			idx = line.indexOf(':');
			headers[trim(line.substring(0, idx))] = trim(line
					.substring(idx + 1));
		}
		try {
			if (headers[Stomp.Headers.CONTENT_LENGTH]) {
			    var len = parseInt( headers[Stomp.Headers.CONTENT_LENGTH] );
			    var start = divider + 2;
				body = (''+ data).substring(start, start+len);
			} else {
				// Parse body, stopping at the first \0 found.
				var chr = null;
				for ( var i = divider + 2; i < data.length; i++) {
					chr = data.charAt(i);
					if (chr === '\0') {
						break;
					}
					body += chr;
				}
			}
			return Stomp.frame(command, headers, body);
		} catch (err) {
		    debug( err );
			return Stomp.frame('ERROR', headers, "Error parsing frame: "
					+ err.description);
		}
	};

	Stomp.marshal = function(command, headers, body) {
		return Stomp.frame(command, headers, body).toString() + '\0';
	};

	Stomp.client = function(url) {

		var that, ws, login, passcode;
		var counter = 0; // used to index subscribers
		// subscription callbacks indexed by subscriber's ID
		var subscriptions = {};

		debug = function(str) {
			if (that.debug) {
				that.debug(str);
			}
		};

		onmessage = function(evt) {
			debug('<<< ' + evt.data);
			var frame = Stomp.unmarshal(evt.data);
			if (frame.command == "CONNECTED") {
				var version = frame.headers[Stomp.Headers.VERSION];
				that.version = version;
				if (that.connectCallback) {
					that.connectCallback(frame);
				}
			} else if (frame.command == "MESSAGE") {
			    var subscription_id = '' + frame.headers.subscription;
				var onreceive = subscriptions['' + frame.headers.subscription];
				if (onreceive) {
					onreceive(frame);
				}
			} else if (frame.command == "RECEIPT" && that.onreceipt) {
				that.onreceipt(frame);
			} else if (frame.command == "ERROR" && that.onerror) {
				that.onerror(frame);
			}
		};

		transmit = function(command, headers, body) {
			var out = Stomp.marshal(command, headers, body);
			debug(">>> " + out);
			ws.send(out);
		};

		that = {};

		that.connect = function(login_, passcode_, connectCallback, errorCallback) {
			debug("Opening Web Socket...");
                        var wsClass = null;
                        if ( typeof WebSocket != 'undefined' ) {
                          wsClass = WebSocket;
                        } else if ( typeof MozWebSocket != 'undefined' ) {
                          wsClass = MozWebSocket;
                        }

			ws = new wsClass(url);
			ws.onmessage = onmessage;
			ws.onclose = function() {
				var msg = "Whoops! Lost connection to " + url;
				debug(msg);
				if (errorCallback) {
					errorCallback(msg);
				}
			};
			ws.onopen = function() {
				debug('Web Socket Opened...');
				var headers = {
					login : login,
					passcode : passcode
				};
				headers[Stomp.Headers.ACCEPT_VERSION] = Stomp.Versions.supportedVersions();
				transmit("CONNECT", headers);
			};
			login = login_;
			passcode = passcode_;
			that.connectCallback = connectCallback;
		};

		that.disconnect = function(disconnectCallback) {
			transmit("DISCONNECT");
			ws.close();
			if (disconnectCallback) {
				disconnectCallback();
			}
		};

		that.waitForDisconnect = function() {
			ws.waitForClosedState();
		};

		that.send = function(destination, headers, body) {
			var headers = headers || {};
			headers.destination = destination;
			transmit("SEND", headers, body);
		};

		that.subscribe = function(destination, callback, headers) {
			var headers = headers || {};
			var subscription_id = "sub-" + counter++;
			headers.destination = destination;
			headers.id = subscription_id;
			debug( "SUBSCRIBE---> " + subscription_id + " == " + callback );
			subscriptions['' + subscription_id] = callback;
			debug( subscriptions['' + subscription_id] );
			transmit("SUBSCRIBE", headers);
			return subscription_id;
		};

		that.unsubscribe = function(id, headers) {
			var headers = headers || {};
			headers.id = id;
			delete subscriptions[id];
			transmit("UNSUBSCRIBE", headers);
		};

		that.begin = function(transaction, headers) {
			var headers = headers || {};
			headers.transaction = transaction;
			transmit("BEGIN", headers);
		};

		that.commit = function(transaction, headers) {
			var headers = headers || {};
			headers.transaction = transaction;
			transmit("COMMIT", headers);
		};

		that.abort = function(transaction, headers) {
			var headers = headers || {};
			headers.transaction = transaction;
			transmit("ABORT", headers);
		};

		that.ack = function(message_id, headers) {
			var headers = headers || {};
			headers["message-id"] = message_id;
			transmit("ACK", headers);
		};
		
		that.nack = function(message_id, headers) {
			// TODO: Add nack functionality.
		}
		
		return that;
	};

	window.Stomp = Stomp;

})(window);