validacion formulario de contacto

<?php
/**
 * Contact form functionality
 * Used within the loop
 * @link https://developer.wordpress.org/reference/functions/wp_nonce_field/
 * @link https://codex.wordpress.org/Class_Reference/WP_Error
 */

if ( ! defined( 'ABSPATH' ) ) exit;

global $reg_errors;
$reg_errors = new WP_error;

$response = "";

//response messages
//$not_human       = "Human verification incorrect.";
$email_invalid   = "Email Address Invalid.";
$name_required   = "Name Required.";
$email_required  = "Email Address Required.";
$phone_required  = "Phone Required.";
$text_required   = "Message Text Required.";
$missing_content = "Please supply all information.";
$message_unsent  = "Message was not sent. Try Again.";
$message_sent    = "Thanks! Your message has been sent.";
$recaptcha_required = "Are you robot?";


//user posted variables
$name = isset ($_POST['message_name'])? esc_sql(sanitize_text_field($_POST['message_name'])):"";
$email = isset($_POST['message_email'])? esc_sql(sanitize_text_field(sanitize_email($_POST['message_email']))):"";
$phone = isset($_POST['message_phone'])? esc_sql(sanitize_text_field($_POST['message_phone'])):"";
$message = isset($_POST['message_text'])? esc_sql(sanitize_text_field($_POST['message_text'])):"";

//$human = $_POST['message_human'];

//php mailer variables
function my_contact_form(){
if (isset($_POST['gymclub_nonce_field']) && wp_verify_nonce( $_POST['gymclub_nonce_field'], 'custom_action_nonce')){

         $to = get_option('gym_contact_admin_email');
         $name     = sanitize_text_field($_POST['message_name']);
         $email    = sanitize_email($_POST['message_email']);
         $phone    = sanitize_text_field($_POST['message_phone']);
         $message    = wp_kses_data($_POST['message_text']);
         $subject = "Someone sent a message from " . get_bloginfo('name');

         $headers = 'From: '. $name . ' <' . $email . '>' .
         $sent = wp_mail( $to, $subject, $message, $headers );

           if ($sent){

            $r = array(
                  'name'  => $name,
                  'email' => $email,
                  'phone' => $phone,
                  'message' => $message,
                  'time' => current_time( 'mysql' )
            );
             wp_send_json_success($r);
           } else {
            $r = array('message' => 'Mail Error');
            wp_send_json_error($r);
           }

    }
       $r = array('message' => 'Validate Error' );
           wp_send_json_error($r);

   }

// WordPress Ajax
add_action( 'wp_ajax_my_contact', 'my_contact_form' );
add_action( 'wp_ajax_nopriv_my_contact', 'my_contact_form' );



// On send - works but prob not best practice https://codex.wordpress.org/Plugin_API/Action_Reference/admin_post_(action)
 if (isset($_POST['submit']) && isset($_POST['g-recaptcha-response'])) {

  // Recaptcha fail
  if ( empty($_POST['g-recaptcha-response']) ) {
    $reg_errors->add("error", $recaptcha_required);
     }

  if (empty($_POST['message_name'])) {
    $reg_errors->add("error", $name_required);
  }

  if (empty($_POST['message_email'])) {
    $reg_errors->add("error", $email_required);
  }

  if (empty($_POST['message_phone'])) {
    $reg_errors->add("error", $phone_required);
  }

  if (empty($_POST['message_text'])) {
    $reg_errors->add("error", $text_required);
  }

  //We check that the field Email is valid
  if(!is_email($_POST['message_email'])) {
   $reg_errors->add("error", $email_invalid);
   }

  //validate presence of name and message

  if (count($reg_errors->get_error_messages()) == 0) {

      $sent = wp_mail($to, $subject, $message, $headers);

        gym_contact_create_entry($name, $email, $phone, $message );

        if($sent) {
          unset($name);
          unset($email);
          unset($phone);
          unset($message);?>
          <div class="alert alert-danger" role="alert">
               <?php echo $message_sent; ?>
          </div>

        <?php }else { ?>
          <div class="alert alert-success" role="alert">
             <?php echo $message_unsent; ?>
         </div>
        <?php }

   }

 }


function gym_contact_create_entry($name, $email, $phone, $message ) {
  global $wpdb;
  $table_name = $wpdb->prefix . 'contact';

  $wpdb->insert(
        $table_name,
        array(
            'name' => $name,
            'email' => $email,
            'phone' => $phone,
            'message' => $message,
            'time' => current_time( 'mysql' )
        )
    );
}

 ?>


 <?php get_header(); ?>

        <?php if ( have_posts() ) : the_post(); ?>

            <?php include_once( 'page_contact.php' ); ?>

        <?php endif; ?>

<?php get_footer(); ?>