[FEATURE] add offer autobridging

Author: boxbag

src/js/ripple/autobridgecalculator.js

@@ -0,0 +1,106 @@
+'use strict';
+
+var _ = require('lodash');
+var assert = require('assert');
+var SerializedObject = require('./serializedobject').SerializedObject;
+var Types = require('./serializedtypes');
+var Amount = require('./amount').Amount;
+
+var IOU_SUFFIX = '/000/rrrrrrrrrrrrrrrrrrrrrhoLvTp';
+var OrderBookUtils = {};
+
+function assertValidNumber(number, message) {
+  assert(!_.isNull(number) && !isNaN(number), message);
+}
+
+/**
+ * Casts and returns offer's taker gets funded amount as a default IOU amount
+ *
+ * @param {Object} offer
+ * @return {Amount}
+ */
+
+OrderBookUtils.getOfferTakerGetsFunded = function(offer) {
+  assertValidNumber(offer.taker_gets_funded, 'Taker gets funded is invalid');
+
+  return Amount.from_json(offer.taker_gets_funded + IOU_SUFFIX);
+};
+
+/**
+ * Casts and returns offer's taker pays funded amount as a default IOU amount
+ *
+ * @param {Object} offer
+ * @return {Amount}
+ */
+
+OrderBookUtils.getOfferTakerPaysFunded = function(offer) {
+  assertValidNumber(offer.taker_pays_funded, 'Taker gets funded is invalid');
+
+  return Amount.from_json(offer.taker_pays_funded + IOU_SUFFIX);
+};
+
+/**
+ * Get offer taker gets amount
+ *
+ * @param {Object} offer
+ *
+ * @return {Amount}
+ */
+
+OrderBookUtils.getOfferTakerGets = function(offer) {
+  assert(typeof offer, 'object', 'Offer is invalid');
+
+  return Amount.from_json(offer.TakerGets + IOU_SUFFIX);
+};
+
+/**
+ * Retrieve offer quality
+ *
+ * @param {Object} offer
+ * @param {Currency} currencyGets
+ */
+
+OrderBookUtils.getOfferQuality = function(offer, currencyGets) {
+  var amount;
+
+  if (currencyGets.has_interest()) {
+    // XXX Should use Amount#from_quality
+    amount = Amount.from_json(
+      offer.TakerPays
+    ).ratio_human(offer.TakerGets, {
+      reference_date: new Date()
+    });
+  } else {
+    amount = Amount.from_json(offer.quality + IOU_SUFFIX);
+  }
+
+  return amount;
+};
+
+/**
+ * Formats an offer quality amount to a hex that can be parsed by
+ * Amount.parse_quality
+ *
+ * @param {Amount} quality
+ *
+ * @return {String}
+ */
+
+OrderBookUtils.convertOfferQualityToHex = function(quality) {
+  assert(quality instanceof Amount, 'Quality is not an amount');
+
+  var so = new SerializedObject();
+  Types.Quality.serialize(so, quality.to_text() + IOU_SUFFIX);
+
+  return so.to_hex();
+};
+
+/**
+ *
+ */
+
+OrderBookUtils.normalizeAmount = function(value) {
+  return Amount.from_json(value + IOU_SUFFIX);
+};
+
+module.exports = OrderBookUtils;