Modifier un code php

<?php
if($_POST)
{
 //Sanitize input data using PHP filter_var().
    $name      = filter_var($_POST["name"], FILTER_SANITIZE_STRING);
    $email     = filter_var($_POST["email"], FILTER_SANITIZE_EMAIL);
    $code   = filter_var($_POST["code"], FILTER_SANITIZE_NUMBER_INT);
    $mob   = filter_var($_POST["mob"], FILTER_SANITIZE_NUMBER_INT);
    $subject        = filter_var($_POST["subject"], FILTER_SANITIZE_STRING);
    $message        = filter_var($_POST["msg"], FILTER_SANITIZE_STRING);
 
    $to_email       = "noreply@resulthosting.in"; //Recipient email, Replace with own email here
 $from_email  = "noreply@resulthosting.in"; //From email address (eg: no-reply@YOUR-DOMAIN.com)
 
    //check if its an ajax request, exit if not
    if(!isset($_SERVER['HTTP_X_REQUESTED_WITH']) AND strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) != 'xmlhttprequest') {
        $output = json_encode(array( //create JSON data
            'type'=>'error',
            'text' => 'Sorry Request must be Ajax POST'
        ));
        die($output); //exit script outputting json data
    }
   
   
    //additional php validation
    if(strlen($name)<4){ // If length is less than 4 it will output JSON error.
        $output = json_encode(array('type'=>'error', 'text' => 'Name is too short or empty!'));
        die($output);
    }
    if(!filter_var($email, FILTER_VALIDATE_EMAIL)){ //email validation
        $output = json_encode(array('type'=>'error', 'text' => 'Please enter a valid email!'));
        die($output);
    }
    if(!filter_var($code, FILTER_VALIDATE_INT)){ //check for valid numbers in country code field
        $output = json_encode(array('type'=>'error', 'text' => 'Enter only digits in country code'));
        die($output);
    }
    if(!filter_var($mob, FILTER_SANITIZE_NUMBER_FLOAT)){ //check for valid numbers in phone number field
        $output = json_encode(array('type'=>'error', 'text' => 'Enter only digits in phone number'));
        die($output);
    }
    if(strlen($subject)<3){ //check emtpy subject
        $output = json_encode(array('type'=>'error', 'text' => 'Subject is required'));
        die($output);
    }
    if(strlen($message)<3){ //check emtpy message
        $output = json_encode(array('type'=>'error', 'text' => 'Too short message! Please enter something.'));
        die($output);
    }
   
    //email body
    $message_body = $message."\n\n".$name."\nEmail : ".$email."\nPhone Number : (".$code.") ". $mob ;

 ### Attachment Preparation ###
 $file_attached = false;
 if(isset($_FILES['file_attach'])) //check uploaded file
 {
  //get file details we need
  $file_tmp_name    = $_FILES['file_attach']['tmp_name'];
  $file_name     = $_FILES['file_attach']['name'];
  $file_size     = $_FILES['file_attach']['size'];
  $file_type     = $_FILES['file_attach']['type'];
  $file_error    = $_FILES['file_attach']['error'];

  //exit script and output error if we encounter any
  if($file_error>0)
  {
   $mymsg = array( 
   1=>"The uploaded file exceeds the upload_max_filesize directive in php.ini", 
   2=>"The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form", 
   3=>"The uploaded file was only partially uploaded", 
   4=>"No file was uploaded", 
   6=>"Missing a temporary folder" ); 
   
   $output = json_encode(array('type'=>'error', 'text' => $mymsg[$file_error]));
   die($output); 
  }
  
  //read from the uploaded file & base64_encode content for the mail
  $handle = fopen($file_tmp_name, "r");
        $content = fread($handle, $file_size);
        fclose($handle);
  $encoded_content = chunk_split(base64_encode($content));
  //now we know we have the file for attachment, set $file_attached to true
  $file_attached = true;
 }
 

 if($file_attached) //continue if we have the file
 {
  $boundary = md5("encrypt"); 
  
  //header
  $headers = "MIME-Version: 1.0\r\n"; 
  $headers .= "From:".$from_email."\r\n"; 
  $headers .= "Reply-To: ".$email."" . "\r\n";
  $headers .= "Content-Type: multipart/mixed; boundary = $boundary\r\n\r\n"; 

  //plain text 
  $body = "--$boundary\r\n";
  $body .= "Content-Type: text/plain; charset=ISO-8859-1\r\n";
  $body .= "Content-Transfer-Encoding: base64\r\n\r\n"; 
  $body .= chunk_split(base64_encode($message_body)); 
 
  //attachment
  $body .= "--$boundary\r\n";
  $body .="Content-Type: $file_type; name=\"$file_name\"\r\n";
  $body .="Content-Disposition: attachment; filename=\"$file_name\"\r\n";
  $body .="Content-Transfer-Encoding: base64\r\n";
  $body .="X-Attachment-Id: ".rand(1000,99999)."\r\n\r\n"; 
  $body .= $encoded_content; 

 }else{
  //proceed with PHP email.
  $headers = "From:".$from_email."\r\n".
  'Reply-To: '.$email.'' . "\n" .
  'X-Mailer: PHP/' . phpversion();
  $body = $message_body;
 }

 $send_mail = mail($to_email, $subject, $body, $headers);
   

    if(!$send_mail)
    {
        //If mail couldn't be sent output error. Check your PHP email configuration (if it ever happens)
        $output = json_encode(array('type'=>'error', 'text' => 'Could not send mail!'));
        die($output);
    }else{
        $output = json_encode(array('type'=>'message', 'text' => 'Hello! '.$name .' We Have Got your email, You Will Also Get An Email Copy Do Check Your Mailbox..'));
        die($output);
    }
}
?>