const ObservableStore = require('obs-store') const extend = require('xtend') const log = require('loglevel') // every three seconds when an incomplete tx is waiting const POLLING_INTERVAL = 3000 class ShapeshiftController { /** * Controller responsible for managing the list of shapeshift transactions. On construction, it initiates a poll * that queries a shapeshift.io API for updates to any pending shapeshift transactions * * @typedef {Object} ShapeshiftController * @param {object} opts Overrides the defaults for the initial state of this.store * @property {array} opts.initState initializes the the state of the ShapeshiftController. Can contain an * shapeShiftTxList array. * @property {array} shapeShiftTxList An array of ShapeShiftTx objects * */ constructor (opts = {}) { const initState = extend({ shapeShiftTxList: [], }, opts.initState) this.store = new ObservableStore(initState) this.pollForUpdates() } /** * Represents, and contains data about, a single shapeshift transaction. * @typedef {Object} ShapeShiftTx * @property {string} depositAddress - An address at which to send a crypto deposit, so that eth can be sent to the * user's Metamask account * @property {string} depositType - An abbreviation of the type of crypto currency to be deposited. * @property {string} key - The 'shapeshift' key differentiates this from other types of txs in Metamask * @property {number} time - The time at which the tx was created * @property {object} response - Initiated as an empty object, which will be replaced by a Response object. @see {@link * https://developer.mozilla.org/en-US/docs/Web/API/Response} */ // // PUBLIC METHODS // /** * A getter for the shapeShiftTxList property * * @returns {array} * */ getShapeShiftTxList () { const shapeShiftTxList = this.store.getState().shapeShiftTxList return shapeShiftTxList } /** * A getter for all ShapeShiftTx in the shapeShiftTxList that have not successfully completed a deposit. * * @returns {array} Only includes ShapeShiftTx which has a response property with a status !== complete * */ getPendingTxs () { const txs = this.getShapeShiftTxList() const pending = txs.filter(tx => tx.response && tx.response.status !== 'complete') return pending } /** * A poll that exists as long as there are pending transactions. Each call attempts to update the data of any * pendingTxs, and then calls itself again. If there are no pending txs, the recursive call is not made and * the polling stops. * * this.updateTx is used to attempt the update to the pendingTxs in the ShapeShiftTxList, and that updated data * is saved with saveTx. * */ pollForUpdates () { const pendingTxs = this.getPendingTxs() if (pendingTxs.length === 0) { return } Promise.all(pendingTxs.map((tx) => { return this.updateTx(tx) })) .then((results) => { results.forEach(tx => this.saveTx(tx)) this.timeout = setTimeout(this.pollForUpdates.bind(this), POLLING_INTERVAL) }) } /** * Attempts to update a ShapeShiftTx with data from a shapeshift.io API. Both the response and time properties * can be updated. The response property is updated with every call, but the time property is only updated when * the response status updates to 'complete'. This will occur once the user makes a deposit as the ShapeShiftTx * depositAddress * * @param {ShapeShiftTx} tx The tx to update * */ async updateTx (tx) { try { const url = `https://shapeshift.io/txStat/${tx.depositAddress}` const response = await fetch(url) const json = await response.json() tx.response = json if (tx.response.status === 'complete') { tx.time = new Date().getTime() } return tx } catch (err) { log.warn(err) } } /** * Saves an updated to a ShapeShiftTx in the shapeShiftTxList. If the passed ShapeShiftTx is not in the * shapeShiftTxList, nothing happens. * * @param {ShapeShiftTx} tx The updated tx to save, if it exists in the current shapeShiftTxList * */ saveTx (tx) { const { shapeShiftTxList } = this.store.getState() const index = shapeShiftTxList.indexOf(tx) if (index !== -1) { shapeShiftTxList[index] = tx this.store.updateState({ shapeShiftTxList }) } } /** * Removes a ShapeShiftTx from the shapeShiftTxList * * @param {ShapeShiftTx} tx The tx to remove * */ removeShapeShiftTx () { const { shapeShiftTxList } = this.store.getState() const index = shapeShiftTxList.indexOf(index) if (index !== -1) { shapeShiftTxList.splice(index, 1) } this.updateState({ shapeShiftTxList }) } /** * Creates a new ShapeShiftTx, adds it to the shapeShiftTxList, and initiates a new poll for updates of pending txs * * @param {string} depositAddress - An address at which to send a crypto deposit, so that eth can be sent to the * user's Metamask account * @param {string} depositType - An abbreviation of the type of crypto currency to be deposited. * */ createShapeShiftTx (depositAddress, depositType) { const state = this.store.getState() let { shapeShiftTxList } = state var shapeShiftTx = { depositAddress, depositType, key: 'shapeshift', time: new Date().getTime(), response: {}, } if (!shapeShiftTxList) { shapeShiftTxList = [shapeShiftTx] } else { shapeShiftTxList.push(shapeShiftTx) } this.store.updateState({ shapeShiftTxList }) this.pollForUpdates() } } module.exports = ShapeshiftController