class Currency {

        constructor() {
            this.initCurrency();
        }

        static init() {
            return new Currency();
        }

        initCurrency() {
            let $currencyList = $('#currencyList');

            if (!$currencyList.length) {
                return false;
            }

            this.getCurrency('USD', 'RUB', '#curUSD');
            this.getCurrency('EUR', 'RUB', '#curEUR');
            this.getCurrency('GBP', 'RUB', '#curUK');
        }

        getCurrency(from, to, selector) {
            $.ajax({
                url: `//currency-api.appspot.com/api/${from}/${to}.jsonp`,
                dataType: "jsonp",
                data: {amount: '1.00'},
                async: false,
                success: $.proxy(function(res) {
                    if (res.success) {
                        this.currencyValue(selector, res.rate);
                    }
                }, this)
            });
        }

        currencyValue(selector, value) {
            let cur = parseFloat(value).toFixed(2);
            $(selector).text(cur);
        }

    }