function zsay(s) {
  function z(token) {
    switch (token[0]) {
    case 'zext':
        return zify(token[1]).toLowerCase();
    case 'zeep':
        return token[1];
    }
  }
  return zeparate(s).map(z).reduce((a,b) => a + b);
}

function zeparate(s) {
  function group(c) {
    return 'abcedefghijklmnopqrstuvwxyzABCEDEFGHIJKLMNOPQRSTUVWXYZ0123456789[]'.indexOf(c) != -1;
  }
  var body = s;
  var res = [];
  var ztype = undefined;
  var val = undefined;
  while (body) {
    if (group(body[0])) {
      ztype = 'zext';
      val = span(group, body);
    } else {
      ztype = 'zeep';
      val = span((c) => !group(c), body);
    }
    body = val[1];
    res.push([ztype, val[0]]);
  }
  return res;
}

function span(test, m) {
  var border = 0;
  for (var i = 0; i < m.length; i++) {
    if (!test(m[i]))
      break;
    border++;
  }
  return [m.substring(0, border), m.substring(border, m.length)];
}

function zify(s) {
  var body = s;
  while (true) {
    var len = body.length;
    if (len < 4) {
      return 'z'.repeat(4 - len) + body;
    } else if (len == 4) {
      return 'z' + body.substring(1, body.length);
    } else if (hasVowel(body)) {
      body = dropVowel(body);
    } else {
      body = body.substring(1, body.length);
    }
  }
}

function hasVowel(s) {
  for (var i = 0; i < s.length; i++)
    if (isVowel(s[i]))
      return true;
  return false;
}

function dropVowel(s) {
  for (var i = 0; i < s.length; i++)
    if (isVowel(s[i]))
      return s.replace(new RegExp(s[i], ''), '');
  return s;
}

function isVowel(c) {
  return 'aeiouAEIOU'.indexOf(c) != -1;
}