PHP file to generate random 6 digit unique Alpha Numeric Based a number (id)

random_unique.php

      // Algo that generates unique number from id of php 
      // Algo V1.0 by Salman Qureshi (@hotheadhacker) date 08/11/2021
      // TODO: Future add timestamp base uniqueness too 
      public function codeGenerator($id){
         // for len 6

         //Step 1: Get Base64
         $code = base64_encode($id);
         

         //Step 2: Strip '==' if present
         $codeStripped = str_replace('=', '', $code);

         //Step 3: Compare if string has been stripped and if present convert to ASCII to reduce the code length
         if($code !== $codeStripped){
            $rand = rand(65,122);
            if($rand >90 && $rand <97){ //to ignore non url characters
               $ascii = $rand;
            }else{
               $ascii = chr($rand);
            }

            $code = $codeStripped. $ascii;
            echo $code;

         }else{ //no '=' signs present
            $code = $codeStripped;
         }

         //Step 4: Shuffle Characters
         $code = str_shuffle($code);

         //Step 5: If length if > 6 we will trim it, to make code shorter
         if(strlen($code > 6)){
            $code = substr($code,0,6);
         }

         //Step 6: Convert Mix Random Case
         for ($i=0, $c=strlen($code); $i<$c; $i++)
         $code[$i] = (rand(0, 100) > 50
         ? strtoupper($code[$i])
         : strtolower($code[$i]));



         //Step 7: Shuffle again Characters to increase uniquenes
         $code = str_shuffle($code);

         //Done and Return
         return $code;
         
        
      }