/**
 * Generates RFC4122 version 4 guid ()
 */

var crypto = (typeof window !== 'undefined') ? (window.crypto || window.msCrypto) : null;

function _cryptoUuidv4() {
  return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
    (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
  )
}

function _uuidv4() {
    return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
    (c ^ Math.random() * 16 >> c / 4).toString(16)
  )
}

export default function random() {
  var hasCrypto = crypto != 'undefined' && crypto !== null;
  var hasRandomValues = hasCrypto && (typeof(crypto.getRandomValues) != 'undefined');  
  var uuid = hasRandomValues ? _cryptoUuidv4 : _uuidv4;
  return uuid().replace(/-/g, '');
}