Mixed encoding and make everything UTF-8

utf-correction.php

<?php
/*
* @exampple: echo utf_correction('محتوای میکس شده و بخش سالم');
* @link: https://stackoverflow.com/questions/48948340/mixed-encoding-and-make-everything-utf-8
**/
function utf_correction(''){
  $str_hex =  bin2hex($str);
  $str = hex2bin($str_hex);
  $fixed = preg_replace_callback(
      '/\\P{Arabic}+/u', 
      function (array $m) { return iconv('UTF-8', 'ISO-8859-1', $m[0]); }, 
      $str
  );
  return $fixed;
}