var util = require('util'),
    Socket = require('net').Socket,
    EventEmitter = require('events').EventEmitter,
    MSNPassport = require(__dirname + '/msn.passport.js');

/**
 * Socket logic
 */
var MSNSocket = function(host, port) {
  EventEmitter.call(this);
  var that = this;
  this._trid = 0;
  this.cmdBuffer = [];

  var sock = this.socket = new Socket();
  sock.connect(port || 1863, host || 'messenger.hotmail.com');
  sock.on('connect', function() {
    that.emit('log', 'Connected');
    that.emit('connect');
  });

  sock.on('data', function(data) {
    var str = data.toString();
    that.emit('log', str);
    that.emit('data', str);
  });

  sock.on('close', function() {
    that.emit('log', 'Disconnected!');
    that.emit('close');
  });
};
util.inherits(MSNSocket, EventEmitter);

MSNSocket.prototype.trid = function() {
  return ++this._trid;
};

MSNSocket.prototype.send = function(data, callback) {
  this.cmdBuffer.push({ "data": data,
    "callback" : callback });
  this.drain();
};

MSNSocket.prototype.drain = function() {
  var that = this;
  var cmd = this.cmdBuffer[0];
  this.emit('log', 'Sending ' + cmd.data);
  this.socket.write(cmd.data + '\r\n', function() {
    cmd.callback && cmd.callback();
    that.cmdBuffer.shift();
    if(that.cmdBuffer.length !== 0) {
      that.drain();
    }
  });
};



/**
 * Main logic
 */
var MSNProtocol = function(username, password) {
  this.user = username;
  this.pass = password;
  this.verbose = true;

  EventEmitter.call(this);
  var that = this;

  this.connect();

  this.on('login', function(status) {
    if(status === 'success') {
      that.sock.send('CHG 8 BSY 0');
    }
  });
};
util.inherits(MSNProtocol, EventEmitter);

MSNProtocol.prototype.connect = function(host, port) {
  var that = this;
  var tmpTrid = (this.sock)? this.sock._trid: 0;
  var sock = this.sock = new MSNSocket(host, port);
  sock._trid = tmpTrid;
  sock.on('connect', function() {
    sock.send('VER ' + sock.trid() + ' MSNP8');
    sock.send('CVR ' + sock.trid() + ' 0x0409 linux 6.0 i386 NODEMSGR 6.0.0602 MSMSGS ' + that.user);
    sock.send('USR ' + sock.trid() + ' TWN I ' + that.user);
  });

  sock.on('data', function(data) {
    if(data.indexOf('XFR') !== -1) {
      that.doXFR(data);
      return sock;
    }

    if(data.indexOf('TWN S') !== -1) {
      that.doLogin(data);
    }

    if(data.indexOf('USR ' + that.sock._trid + ' OK') !== -1) {
      that.emit('login', 'success');
      sock.removeAllListeners('data');
    }

  });

  sock.on('log', function(data) {
    if(that.verbose) {
      util.log(data);
    }
  });

  return sock;
};

MSNProtocol.prototype.doXFR = function(res) {
  var start = res.indexOf('NS ') + 3;
  var str = res.substr(start);
  var stop = str.indexOf(' 0 ');
  str = str.substr(0, stop).split(':');
  this.connect(str[0], str[1]);
};

MSNProtocol.prototype.doLogin = function(res) {
  var that = this;
  var challenge = res.substr(res.indexOf('TWN S') + 6);
  MSNPassport(challenge, this.user, this.pass, function(status, ticket) {
    if(status === 'success') {
      that.sock.send('USR ' + that.sock.trid() + ' TWN S ' + ticket);
      delete that.pass;
    } else {
      that.emit('login', 'failed');
    }
  });
};