mail.php sa integriranom captcha provjerom

<?php

        $email=isset($_POST['email']) ? $_POST['email'] : '';
        $comment=isset($_POST['poruka']) ? $_POST['poruka']: '';
        $captcha;
        $primatelj='midzan21@gmail.com';
        $email = filter_var($email, FILTER_SANITIZE_EMAIL);
        if(isset($_POST['g-recaptcha-response']))
          $captcha=$_POST['g-recaptcha-response'];

        if(!$captcha){
          echo '<h2>olim Vas da riješite captchu!</h2>';
          exit;
        }
        $response=json_decode(file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=MY_SECRET_CODE&response=".$captcha."&remoteip=".$_SERVER['REMOTE_ADDR']), true);
        if($response['success'] == false)
        {
          echo '<h2>Spamerima zabranjen pristup!</h2>';
        }
        else
        {
            if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
                $headers = 'MIME-Version: 1.0' . "\r\n";
                $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
                $headers .= 'Od:' . $email. "\r\n";
                $headers .= 'Cc:' . $email. "\r\n";
                mail($primatelj, $email, $headers, $comment);
            }
                echo '<h2>Vaša poruka je poslana, odgovoriti ću Vam u najkraćem mogućem roku.</h2>';
        }
?>