const ObservableStore = require('obs-store') const extend = require('xtend') // every ten minutes const POLLING_INTERVAL = 600000 class CurrencyController { constructor (opts = {}) { const initState = extend({ currentCurrency: 'usd', conversionRate: 0, conversionDate: 'N/A', }, opts.initState) this.store = new ObservableStore(initState) } // // PUBLIC METHODS // getCurrentCurrency () { return this.store.getState().currentCurrency } setCurrentCurrency (currentCurrency) { this.store.updateState({ currentCurrency }) } getConversionRate () { return this.store.getState().conversionRate } setConversionRate (conversionRate) { this.store.updateState({ conversionRate }) } getConversionDate () { return this.store.getState().conversionDate } setConversionDate (conversionDate) { this.store.updateState({ conversionDate }) } updateConversionRate () { const currentCurrency = this.getCurrentCurrency() return fetch(`https://api.infura.io/v1/ticker/eth${currentCurrency.toLowerCase()}`) .then(response => response.json()) .then((parsedResponse) => { this.setConversionRate(Number(parsedResponse.bid)) this.setConversionDate(Number(parsedResponse.timestamp)) }).catch((err) => { if (err) { console.warn(`MetaMask - Failed to query currency conversion:`, currentCurrency, err) this.setConversionRate(0) this.setConversionDate('N/A') } }) } scheduleConversionInterval () { if (this.conversionInterval) { clearInterval(this.conversionInterval) } this.conversionInterval = setInterval(() => { this.updateConversionRate() }, POLLING_INTERVAL) } } module.exports = CurrencyController