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

class LuckyNumberGenerator {
  constructor(numbersCount = 312) {
    this.numbers = Array(numbersCount).fill(false);
    this.numbersCount = numbersCount;
  }

  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, 0, this.numbersCount - 1);
    
    // Ensure the number hasn't been drawn yet.
    while (this.numbers[number]) {
      int = (int + 1) % (Math.pow(2, 28)); // Increment the integer, wrapping around if necessary
      number = this.reduce(int, 0, this.numbersCount - 1);
    }

    this.numbers[number] = true; // Mark the number as drawn
    return number;
  }

  selectNumbers(payload, secret, count = 6) {
    const numbers = [];
    for (let i = 0; i < count; i++) {
      numbers.push(this.selectNumber(payload + i, secret)); // Append an index to the payload for unique hashes
    }
    return numbers;
  }

  // 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 luckyNumbers = luckyNumbersGenerator.selectNumbers(uid, secret, 6);
// console.log(luckyNumbers); === undefined