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const { createHmac } = require('crypto');

const divisible = (hash, mod) => {
  // So ABCDEFGHIJ should be chunked like  AB CDEF GHIJ
  let val = 0;

  let o = hash.length % 4;
  for (let i = o > 0 ? o - 4 : 0; i < hash.length; i += 4) {
    val = ((val << 16) + parseInt(hash.substring(i, i + 4), 16)) % mod;
  }

  return val === 0;
};
const calculateSlidePointFromHash = function (hash) {
  // In 1 of 15 games the game slides instantly.
  if (divisible(hash, 15)) return 0;

  // Use the most significant 52-bit from the hash to calculate the slide point
  let h = parseInt(hash.slice(0, 52 / 4), 16);
  let e = Math.pow(2, 52);

  return (Math.floor((100 * e - h) / (e - h)) / 100).toFixed(2);
};

// these will be the 10M pre generated rolls to be used
const hashChain = ['random1', 'random2'];

const gameHash = hashChain.pop();

// It's the hash we're gonna be using of the result of a yet to be mined block on the blockchain #792,123
const blockHash = '';

const hash = createHmac('sha256', gameHash).update(blockHash).digest('hex');

const slidePoint = calculateSlidePointFromHash(hash);
console.log({ slidePoint });

000000000000000000007b114ff8e0104b89f0f59354dd768f9c240fd838908a