// Converts seconds to human-readable time
String.prototype.toHHMMSS = function () {
  let sec_num = parseInt(this, 10); // don't forget the second param
  let hours = Math.floor(sec_num / 3600);
  let minutes = Math.floor((sec_num - hours * 3600) / 60);
  let seconds = sec_num - hours * 3600 - minutes * 60;

  if (hours < 10) {
    hours = "0" + hours;
  }
  if (minutes < 10) {
    minutes = "0" + minutes;
  }
  if (seconds < 10) {
    seconds = "0" + seconds;
  }
  return hours + ":" + minutes + ":" + seconds;
};

async function asyncForEach(array, callback) {
  for (let index = 0; index < array.length; index++) {
    await callback(array[index], index, array);
  }
}

function randElement(arr) {
  return arr[Math.floor(Math.random() * arr.length)];
}

function randSort() {
  return 0.5 - Math.random();
}

function chunkSubstr(str, size) {
  const numChunks = Math.ceil(str.length / size);
  const chunks = new Array(numChunks);

  for (let i = 0, o = 0; i < numChunks; ++i, o += size) {
    chunks[i] = str.substr(o, size);
  }

  return chunks;
}

module.exports = {
  asyncForEach,
  randElement,
  randSort,
  chunkSubstr
};