Prevent guest users from booking before waitlists

<?php

/*
 * Prevent guest users from booking before waitlists
 */

add_filter('em_bookings_is_open','my_booking_open', 100, 2);

function my_booking_open( $return, $EM_Bookings ){
  global $wpdb;

  if( get_option('dbem_waitlists_events')  && !is_user_logged_in()  ) {

    $EM_Event = $EM_Bookings->get_event();

	$waitlist_events = get_option('dbem_waitlists_events_default');

	if ( $waitlist_events ){

		if (!empty($EM_Event->event_attributes['waitlist'])) {

		  /* start */
		  if ( isset($_REQUEST['uuid']) ){

			$sql    = 'SELECT booking_status FROM '.EM_BOOKINGS_TABLE. ' WHERE booking_status = 7 AND booking_uuid = %s ';
			$status = $wpdb->get_var( $wpdb->prepare($sql, $_REQUEST['uuid']) );

			if ( $status == 7 ){
				$return = true;
				return $return;
			}

		  }
		  /*  end  */

		  $statuses = array(6);

		  $sql = 'SELECT SUM(booking_spaces) FROM '.EM_BOOKINGS_TABLE. ' WHERE booking_status IN ('. implode(',', $statuses) .') AND event_id=%d';

		  $pending_spaces = $wpdb->get_var( $wpdb->prepare($sql, $EM_Bookings->event_id) );

		  if ( $pending_spaces > 0 ){
            $return = false;
			add_filter('em_event_output_placeholder', 'my_em_bookinform', 100, 3);
		  }


		}

	}

  }


  if( get_option('dbem_waitlists_events')  && is_user_logged_in()  ) {

	/* start */
	if ( isset($_REQUEST['uuid']) ){

	  $sql    = 'SELECT booking_status FROM '.EM_BOOKINGS_TABLE. ' WHERE booking_status = 7 AND booking_uuid = %s ';
	  $status = $wpdb->get_var( $wpdb->prepare($sql, $_REQUEST['uuid']) );

	  if ( $status == 7 ){
		$return = true;
		return $return;
	  }

	}
	/*  end  */

	$current_user = wp_get_current_user(); //$current_user->ID

	$statuses = array(6); //6 - waiting // 7 - approved

	$sql = 'SELECT SUM(booking_spaces) FROM '.EM_BOOKINGS_TABLE. ' WHERE booking_status IN ('. implode(',', $statuses) .') AND event_id=%d AND person_id=%d';

	$pending_spaces = $wpdb->get_var( $wpdb->prepare($sql, $EM_Bookings->event_id, $current_user->ID ) );

	if ( $pending_spaces > 0 && !isset($_REQUEST['uuid']) ){
	  $return = false;
	  add_filter('em_event_output_placeholder', 'my_em_bookinform_already_waiting', 100, 3);
	} else {
	  $return = false;
	  add_filter('em_event_output_placeholder', 'my_em_bookinform', 100, 3);
	}

  }

  return $return;
}

function my_em_bookinform_already_waiting($replace, $EM_Event, $result) {
	if ( $result == '#_BOOKINGFORM' ) {
		include( emp_locate_template('waitlists/already-waiting.php') );
		return ob_get_clean();
	}
    return $replace;
}

function my_em_bookinform($replace, $EM_Event, $result) {
	if ( $result == '#_BOOKINGFORM' ) {
		include( emp_locate_template('waitlists/form.php') );

		echo "<script>";
		include( emp_locate_template('waitlists/waitlists.js') );
		echo "</script>";

		return ob_get_clean();
	}
    return $replace;
}