jingtum-lib/src/orderbook.js

jingtum lib

/**
 * Created by Administrator on 2016/11/22.
 */
var util = require('util');
var Event = require('events').EventEmitter;
var utils = require('./utils');
const currency = require('./config').currency;

function parseKey(key) {
    var parts = key.split(':');
    if (parts.length !== 2) return null;

    function parsePart(part) {
        if (part === currency) return {currency: currency, issuer: ''};
        var _parts = part.split('/');
        if (_parts.length !== 2) return null;
        if (!utils.isValidCurrency(_parts[0])) return null;
        if (!utils.isValidAddress(_parts[1])) return null;
        return {currency: _parts[0], issuer: _parts[1]};
    }

    var gets = parsePart(parts[0]);
    var pays = parsePart(parts[1]);
    if (!gets || !pays) return null;
    return {gets:gets, pays: pays};
}

/**
 * order book stub for all order book
 * key: currency/issuer:currency/issuer
 *  if swt, currency/issuer=SWT
 *  TODO keep every order book up state, and return state when needed
 *  not need to query jingtumd again
 * @param remote
 * @constructor
 */
function OrderBook(remote) {
    Event.call(this);

    var self = this;
    self._remote = remote;
    self._books = {};

    self.on('newListener', function(key, listener) {
        if (key === 'removeListener') return;
        var pair = parseKey(key);
        if (!pair) {
            self.pair = new Error("invalid key");
            return self;
        }
        self._books[key] = listener;
    });
    self.on('removeListener', function(key) {
        var pair = parseKey(key);
        if (!pair) {
            self.pair = new Error("invalid key");
            return self;
        }
        delete self._books[key];
    });
    // same implement as account stub, subscribe all and dispatch
    self._remote.on('transactions', self.__updateBooks.bind(self));
}

OrderBook.prototype.__updateBooks = function(data) {
    var self = this;
    // dispatch
    if (data.meta) {
        var books = utils.affectedBooks(data);
        var _data = {tx: data.transaction, meta: data.meta, 
            engine_result: data.engine_result, engine_result_code: data.engine_result_code,
            engine_result_message: data.engine_result_message, ledger_hash: data.ledger_hash,
            ledger_index: data.ledger_index, validated: data.validated};
        var _tx = utils.processTx(_data, data.transaction.Account);
        for (var i in books) {
            var callback = self._books[books[i]];
            if (callback) callback(_tx);
        }
    }
};

util.inherits(OrderBook, Event);

module.exports = OrderBook;