gekko/portfolioManager.js

/*

  The portfolio manager is responsible for making sure that
  all decisions are turned into orders and make sure these orders
  get executed. Besides the orders the manager also keeps track of
  the client's portfolio.

*/

var _ = require('underscore');
// var EventEmitter = require('events').EventEmitter;
var Util = require("util");
var util = require('./util')
var events = require("events");
var log = require('./log');
var async = require('async');

var Manager = function(conf, checker) {
  this.exchangeSlug = conf.exchange.toLowerCase();

  // create an exchange
  var Exchange = require('./exchanges/' + this.exchangeSlug);
  this.exchange = new Exchange(conf);

  //    state
  this.conf = conf;
  this.portfolio = {};
  this.fee;
  this.order;
  this.action;

  this.currency = conf.currency || 'USD';
  this.asset = conf.asset || 'BTC';

  var error = this.checkExchange();
  if(error && !checker)
    throw error;

  _.bindAll(this);

  if(checker)
    return;

  log.debug('getting balance & fee from', this.exchange.name);
  var prepare = function() {
    this.starting = false;

    log.info('trading at', this.exchange.name, 'ACTIVE');
    log.info(this.exchange.name, 'trading fee will be:', this.fee * 100 + '%');
    log.info('current', this.exchange.name, 'portfolio:');
    _.each(this.portfolio, function(fund) {
      log.info('\t', fund.name + ':', fund.amount);
    });
    this.emit('ready');
  };

  async.series([
    this.setPortfolio,
    this.setFee
  ], _.bind(prepare, this));
}

// teach our Manager events
Util.inherits(Manager, events.EventEmitter);

Manager.prototype.validCredentials = function() {
  return !this.checkExchange();
}

Manager.prototype.checkExchange = function() {
  // what kind of exchange are we dealing with?
  // 
  // name: slug of exchange
  // direct: does this exchange support MKT orders?
  // infinityOrder: is this an exchange that supports infinity 
  //    orders? (which means that it will accept orders bigger then
  //    the current balance and order at the full balance instead)
  // currencies: all the currencies supported by the exchange
  //    implementation in gekko.
  // assets: all the assets supported by the exchange implementation
  //    in gekko.
  var exchanges = [
    {
      name: 'mtgox',
      direct: true,
      infinityOrder: true,
      currencies: [
        'USD', 'EUR', 'GBP', 'AUD', 'CAD', 'CHF', 'CNY',
        'DKK', 'HKD', 'PLN', 'RUB', 'SGD', 'THB'
      ],
      assets: ['BTC'],
      requires: ['key', 'secret'],
      minimalOrder: { amount: 0.01, unit: 'asset' }
    },
    {
      name: 'btce',
      direct: false,
      infinityOrder: false,
      currencies: ['USD', 'RUR', 'EUR'],
      assets: ['BTC'],
      requires: ['key', 'secret'],
      minimalOrder: { amount: 0.01, unit: 'asset' }
    },
    {
      name: 'bitstamp',
      direct: false,
      infinityOrder: false,
      currencies: ['USD'],
      assets: ['BTC'],
      requires: ['user', 'password'],
      minimalOrder: { amount: 1, unit: 'currency' }
    }
  ];
  var exchange = _.find(exchanges, function(e) { return e.name === this.exchangeSlug }, this);
  if(!exchange)
    return 'Gekko does not support the exchange ' + this.exchangeSlug;

  this.directExchange = exchange.direct;
  this.infinityOrderExchange = exchange.infinityOrder;
  if(_.indexOf(exchange.currencies, this.currency) === -1)
    return 'Gekko does not support the currency ' + this.currency + ' at ' + this.exchange.name;

  if(_.indexOf(exchange.assets, this.asset) === -1)
    return 'Gekko does not support the asset ' + this.asset + ' at ' + this.exchange.name;

  var ret;
  _.each(exchange.requires, function(req) {
    if(!this.conf[req])
      ret = this.exchange.name + ' requires "' + req + '" to be set in the config';
  }, this);

  this.minimalOrder = exchange.minimalOrder;

  return ret;

}

Manager.prototype.setPortfolio = function(callback) {
  var set = function(err, portfolio) {
    this.portfolio = portfolio;
    callback();
  };
  this.exchange.getPortfolio(_.bind(set, this));
}

Manager.prototype.setFee = function(callback) {
  var set = function(err, fee) {
    this.fee = fee;
    callback();
  };
  this.exchange.getFee(_.bind(set, this));
}

Manager.prototype.setTicker = function(callback) {
  var set = function(err, ticker) {
    this.ticker = ticker;
    callback();
  }
  this.exchange.getTicker(_.bind(set, this));
}

// return the [fund] based on the data we have in memory
Manager.prototype.getFund = function(fund) {
  return _.find(this.portfolio, function(f) { return f.name === fund});
}
Manager.prototype.getBalance = function(fund) {
  return this.getFund(fund).amount;
}

// This function makes sure order get to the exchange
// and initiates follow up to make sure the orders will
// get executed. This is the backbone of the portfolio 
// manager.
// 
// How this is done depends on a couple of things:
// 
// is this a directExchange? (does it support MKT orders)
// is this a infinityOrderExchange (does it support order
// requests bigger then the current balance?)
Manager.prototype.trade = function(what) {
  if(what !== 'BUY' && what !== 'SELL')
    return;

  var act = function() {
    var amount, price;

    if(what === 'BUY') {

      // do we need to specify the amount we want to buy?
      if(this.infinityOrderExchange)
        amount = 10000;
      else
        amount = this.getBalance(this.currency) / this.ticker.ask;

      // can we just create a MKT order?
      if(this.directExchange)
        price = false;
      else
        price = this.ticker.ask;

      this.buy(amount, price);

    } else if(what === 'SELL') {

      // do we need to specify the amount we want to sell?
      if(this.infinityOrderExchange)
        amount = 10000;
      else
        amount = this.getBalance(this.asset);

      // can we just create a MKT order?
      if(this.directExchange)
        price = false;
      else
        price = this.ticker.bid;
      
      this.sell(amount, price);
    }
  };
  async.series([
    this.setTicker,
    this.setPortfolio
  ], _.bind(act, this));

}

Manager.prototype.getMinimum = function(price) {
  if(this.minimalOrder.unit === 'currency')
    return minimum = this.minimalOrder.amount / price;
  else
    return minimum = this.minimalOrder.amount;
}

// first do a quick check to see whether we can buy
// the asset, if so BUY and keep track of the order
// (amount is in asset quantity)
Manager.prototype.buy = function(amount, price) {
  var currency = this.getFund(this.currency);
  var minimum = this.getMinimum(price);
  if(amount > minimum) {
    log.info('attempting to BUY', this.asset, 'at', this.exchange.name);
    this.exchange.buy(amount, price, this.noteOrder);
    this.action = 'BUY';
  } else
    log.info('wanted to buy but insufficient', this.currency, '(' + amount * price + ') at', this.exchange.name);
}

// first do a quick check to see whether we can sell
// the asset, if so SELL and keep track of the order
// (amount is in asset quantity)
Manager.prototype.sell = function(amount, price) {
  var asset = this.getFund(this.asset);
  var minimum = this.getMinimum(price);
  if(amount > minimum) {
    log.info('attempting to SELL', this.asset, 'at', this.exchange.name);
    this.exchange.sell(amount, price, this.noteOrder);
    this.action = 'SELL';
  } else
    log.info('wanted to sell but insufficient', this.asset, '(' + amount + ') at', this.exchange.name);
}

Manager.prototype.noteOrder = function(order) {
  this.order = order;
  // if after 30 seconds the order is still there
  // we cancel and calculate & make a new one
  setTimeout(this.checkOrder, util.minToMs(0.5));
}

// check wether the order got fully filled
// if it is not: cancel & instantiate a new order
Manager.prototype.checkOrder = function() {
  var finish = function(err, filled) {
    if(!filled) {
      log.info(this.action, 'order was not (fully) filled, canceling and creating new order');
      this.exchange.cancelOrder(this.order);
      return this.trade(this.action);
    }

    log.info(this.action, 'was succesfull');
  }

  this.exchange.checkOrder(this.order, _.bind(finish, this));
}

module.exports = Manager;