// input string : (a,b,(c,d),((e,f),g),h)
// json string  : ["a","b",["c","d"],[["e","f"],"g"],"h"]

function stringToArray($string) {
  /** escape some chars */
  /* escape brackets with :ob: for open bracket and :cb: for close bracket */
  $string = str_replace(array('[', ']'), array(':ob:', ':cb:'), $string);
  /* look for strings like 'string' and escape parentheses with :op: for open parenthesis and :cp: for close parenthesis */
  $string = preg_replace_callback("`'(.*?)'`", function ($matches) {
      return "'".str_replace(array('(', ')'), array(':op:', ':cp:'), $matches[1])."'";
    }, $string);

  /** jsonify string */
  /* replace all strings between , ( ) by "string" */
  $string = preg_replace('`([^,\(\)]+)`', '"$1"', $string);
  /* replace parentheses by brackets */
  $string = str_replace(array('(', ')'), array('[', ']'), $string);

  /* convert json string to php array */
  $array = json_decode($string);

  /* error, bad json string format */
  if (!is_array($array)) {
    echo "Something went wrong, the string <b>$string</b> is not well formatted for json_decode!<br/>";
    exit();
  }

  /* restore escaped characters by their original character and return the array */
  return restoreEscaped($array);
}
function restoreEscaped($array)
{
  /* explore the array recursively and restore the escaped characters when the entry is not an array */
  return array_map(function ($entry) {
    return is_array($entry)
      ? restoreEscaped($entry)
      : str_replace(
          array(':ob:', ':cb:', ':op:', ':cp:'),
          array('[', ']', '(', ')'),
          $entry);
    }, $array);
}

function arrayToString($array)
{
  /* escape the brackets in the array */
  $array = escapeBrackets($array);
  /* convert php array to json string */
  $string = json_encode($array);
  /* replace brackets, double quotes and escaped brackets to match input string format */
  $string = str_replace(array('[', ']', '"', ':ob:', ':cb:'), array('(', ')', '', '[', ']'), $string);

  return $string;
}
function escapeBrackets($array) {
  /* explore the array recursively and escape the brackets when entry is not an array */
  return array_map(function ($entry) {
    return is_array($entry)
      ? escapeBrackets($entry)
      : str_replace(
          array('[', ']'),
          array(':ob:', ':cb:'),
          $entry);
  }, $array);
}

function stringToArray($string) {
  /* escape some chars */
  $string = str_replace(array('[', ']'), array(':ob:', ':cb:'), $string);
  $string = preg_replace_callback("`'(.*?)'`", function ($matches) {
      return "'".str_replace(array('(', ')'), array(':op:', ':cp:'), $matches[1])."'";
    }, $string);
  
  /* jsonify string */
  $string = preg_replace('`([^,\(\)]+)`', '"$1"', $string);
  $string = str_replace(array('(', ')'), array('[', ']'), $string);

  $array = json_decode($string);
  return restoreEscaped($array);
}
function restoreEscaped($array)
{
  return array_map(function ($entry) {
    return is_array($entry)
      ? restoreEscaped($entry)
      : str_replace(
          array(':ob:', ':cb:', ':op:', ':cp:'),
          array('[', ']', '(', ')'),
          $entry);
    }, $array);
}

function arrayToString($array)
{
  $array = escapeBrackets($array);
  $string = json_encode($array);
  $string = str_replace(array('[', ']', '"', ':ob:', ':cb:'), array('(', ')', '', '[', ']'), $string);

  return $string;
}
function escapeBrackets($array) {
  return array_map(function ($entry) {
    return is_array($entry)
      ? escapeBrackets($entry)
      : str_replace(
          array('[', ']'),
          array(':ob:', ':cb:'),
          $entry);
  }, $array);
}

function arrayToString($array)
{
  $string = json_encode($array);
  $string = str_replace(array('[', ']', '"'), array('(', ')', ''), $string);

  return $string;
}

$string = "('1xrWb_VEHEZRY9JJ9v3lYY',#41,'Default',$,$,#619,$,$,.ELEMENT.,(44,59,59,999999),(4,59,59,999999),150000.,$,$)";
echo "string = $string<br/>";

function stringToArray($string) {
  $string = str_replace(array('(', ')'), array('[', ']'), $string);
  $string = preg_replace('`([^,\[\]]+)`', '"$1"', $string);

  return json_decode($string);
}

echo '<pre>';
print_r(stringToArray($string));
echo '</pre>';

string = ('1xrWb_VEHEZRY9JJ9v3lYY',#41,'Default',$,$,#619,$,$,.ELEMENT.,(44,59,59,999999),(4,59,59,999999),150000.,$,$)

Array
(
    [0] => '1xrWb_VEHEZRY9JJ9v3lYY'
    [1] => #41
    [2] => 'Default'
    [3] => $
    [4] => $
    [5] => #619
    [6] => $
    [7] => $
    [8] => .ELEMENT.
    [9] => Array
        (
            [0] => 44
            [1] => 59
            [2] => 59
            [3] => 999999
        )

    [10] => Array
        (
            [0] => 4
            [1] => 59
            [2] => 59
            [3] => 999999
        )

    [11] => 150000.
    [12] => $
    [13] => $
)