let period = 20; // Number of days
var averages = [];
let current_average_sum = 0;
let current_sum = 0;
let current_time = Date.now();
var closing_prices = [];
let market = "ETHBTC"; // maybe an array of different markets?
let candleSize = "1d";
let multiplier = (2 / (period + 1));
let Close = 0;
let EMA = 0;
let SMA = 0;
let previous_ema = 0;

const binance = require('node-binance-api')().options({
    APIKEY: 'xxx', // CHANGE THIS AND THE API SECRET!
    APISECRET: 'xxx',
    useServerTime: true,
    test: true // True = SandboxMode
});

function fetchPrice() {
    binance.candlesticks(market, candleSize, (error, ticks, symbol) => {
        for (i = 0; i < ticks.length; i++) {
            let last_tick = ticks[i];
            let [time, open, high, low, close, volume, closeTime, assetVolume, trades, buyBaseVolume, buyAssetVolume, ignored] = last_tick;
            closing_prices.push(close);
            current_close = closing_prices[i];
            Close = parseFloat(current_close);
        }
        calculateSMA();
        calculateEMA();
    }, {
        limit: period,
        endTime: current_time
    });
}

function calculateSMA() {
    for (i = 0; i < period; i++) {
        selected_elements = closing_prices.slice(0, period);
        for (x = 0; x < (selected_elements.length); x++) {
            current_value = selected_elements[x];
            current_sum += parseFloat(current_value);
        }
        closing_prices.shift();
        averages.push(current_sum / period);
        current_sum = 0;
    }
    SMA = averages[0];
    console.log(SMA + " SMA ");
    return SMA;
}
fetchPrice();

function calculateEMA() {
    if (EMA == 0) {
        EMA = (Close - SMA) * multiplier + SMA;
        console.log(" EMA . " + EMA);
        previous_ema = EMA;
        //return EMA;
        calculateEMA();
    } else {
        for (a = 0; a < period; a++) {
            EMA = (Close - previous_ema) * multiplier + previous_ema;
            console.log(EMA + " ema");
            //console.log(previous_ema + " previous");
            previous_ema = EMA;
        }
    }
}