Reset deleted count for RSVP tickets when all attendees and tickets are removed

functions.php

<?php

/**
 * Custom reset for attendee deletion count if all attendees are deleted
 */

add_action( 'tickets_rsvp_ticket_deleted', 'rt_reset_deleted_data_if_attendee_not_available', 20, 3 );

function rt_reset_deleted_data_if_attendee_not_available( $ticket_id, $event_id, $product_id ) {
	$total_attendees = Tribe__Tickets__Tickets::get_event_attendees_count( $event_id );

	if ( $total_attendees != 0 ) {
		return;
	}

	update_post_meta( $event_id, '_tribe_deleted_attendees_count', 0 );
}