#!/usr/bin/env node
const crypto = require("crypto");

class LuckyNumberGenerator {
  selectNumber(payload, secret) {
    const hmac = cryptolib
      .createHmac("sha512", payload)
      .update(secret)
      .digest("hex");

    let f7 = hmac.substring(0, 7);
    let int = parseInt(f7, 16);
    let number = this.reduce(int, 1, 12);

    return number;
  }

  // use to reduce a number to appropriate size
  reduce = (number, outMin, outMax) =>
    (number % ((outMax - outMin) + 1)) + outMin;
}

// const luckyNumbersGenerator = new LuckyNumberGenerator();
// const uid = '';
// const secret = '';
// const luckyNumber = luckyNumbersGenerator.selectNumber(uid, secret);
// console.log(luckyNumber); === undefined