dm_remote.js

var zmq = require('zmq');
var req = new zmq.socket('req'); 


exports.Start = function (host, port, cb) {
	req.connect('tcp://'+host+':'+port);
    	console.log('Connected to: ' + host + ':' + port);
    	if (cb != null) cb();
}

var callbacks = {} // hash of callbacks. Key is invoId
var invoCounter = 0; // current invocation number is key to access "callbacks".

req.on ('message', function (data) {
	console.log ('data comes in: ' + data);
	var reply = JSON.parse (data.toString());
	switch (reply.what) {
		case 'add user':
			console.log ('We received a reply for: ' + reply.what + ':' + reply.invoId);
			callbacks [reply.invoId] (); // call the stored callback, 0 argument
			delete callbacks [reply.invoId]; // remove from hash
			break;
		case 'add subject':
			console.log ('We received a reply for: ' + reply.what + ':' + reply.invoId);
			callbacks [reply.invoId] (); 
			delete callbacks [reply.invoId]; 
			break;
		case 'get user list':
			console.log ('We received a reply for: ' + reply.what + ':' + reply.invoId);
			callbacks [reply.invoId] (reply.obj); 
			delete callbacks [reply.invoId]; 
			break;
		case 'login':
			console.log ('We received a reply for: ' + reply.what + ':' + reply.invoId);
			callbacks [reply.invoId] (reply.obj);
			delete callbacks [reply.invoId];
			break;
		case 'add private message':
			console.log ('We received a reply for: ' + reply.what + ':' + reply.invoId);
			callbacks [reply.invoId] ();
			delete callbacks [reply.invoId];
			break;
		case 'get private message list':
		case 'get public message list':
		case 'get subject list':
			console.log ('We received a reply for: ' + reply.what + ':' + reply.invoId);
			callbacks [reply.invoId] (reply.obj); // call the stored callback, one argument
			delete callbacks [reply.invoId]; // remove from hash
			break;
		case 'add private message':
		case 'add public message':
			console.log ('We received a reply for add command');
			callbacks [reply.invoId] (); // call the stored callback, no arguments
			delete callbacks [reply.invoId]; // remove from hash
			break;
		default:
			console.log ("Panic: we got this: " + reply.what);
	}
});

req.on('close', function() {
    console.log('Connection closed');
});


function Invo (str, cb) {
	this.what = str;
	this.invoId = ++invoCounter;
	callbacks[invoCounter] = cb;
}

exports.addUser = function (u,p, cb) {
	var invo = new Invo('add user', cb);
	invo.u = u;
	invo.p = p;
	req.send(JSON.stringify(invo));
}

exports.addSubject = function (s, cb) {
	var invo = new Invo('add subject', cb);
	invo.s = s;
	req.send(JSON.stringify(invo));
}


exports.getUserList = function (cb) {
	req.send(JSON.stringify(new Invo ('get user list', cb)));


}

exports.login = function (u, p, cb) {
	var invo = new Invo('login', cb);
	invo.u = u;
	invo.p = p;
	req.send(JSON.stringify(invo));
}

exports.addPrivateMessage = function (msg, cb) {
	var invo = new Invo('add private message', cb);
	invo.msg = msg;
	req.send(JSON.stringify(invo));
}


function getSubject (sbj, cb) {
	var invo = new Invo('get subject',cb);
	invo.sbj = sbj;
	req.send(JSON.stringify(invo));
}

exports.addPublicMessage = function (msg, cb) {
	var invo = new Invo('add public message', cb);
	invo.msg = msg;
	req.send(JSON.stringify(invo));
}

exports.getPublicMessageList = function  (sbj, cb) {
	var invo = new Invo ('get public message list', cb);	
	invo.sbj = sbj;
	req.send (JSON.stringify(invo));
}

exports.getPrivateMessageList = function (u1, u2, cb) {
	invo = new Invo ('get private message list', cb);
	invo.u1 = u1;
	invo.u2 = u2;
	req.send (JSON.stringify(invo));
}

exports.getSubjectList = function (cb) {
	req.send (JSON.stringify(new Invo ('get subject list', cb)));

}

// TODO: complete the rest of the forum functions.