public function get_event_ids( $post_id ) {
		$services = $this->detect_by_id( $post_id );
		if ( ! is_array( $services ) ) {
			$services = array();
		}

		// if this id is not an order id or a ticket id return
		$is_ticket_related = array_intersect( array( 'order', 'ticket', 'attendee', 'product' ), $services );
		if ( ! $is_ticket_related ) {
			return array();
		}

		// if no post type or module class return
		if ( empty( $services['post_type'] ) || empty( $services['class'] ) ) {
			return array();
		}

		$module_class = $services['class'];

		/**
		 * if we have a rsvp order with a unique rsvp order key
		 * change $post_id to the first rsvp post's id
		 */
		if ( ! is_numeric( $post_id ) && 'Tribe__Tickets__RSVP' === $module_class ) {
			$post_id = $this->get_rsvp_post_id_from_order_key( $post_id );
		}
		$event_id_key = $this->ticket_class[ $module_class ]['event_id_key'];
		$event_ids    = array();

		$is_product = array_intersect( array( 'product' ), $services );
		if ( $is_product ) {
			$tribe_for_event = $this->ticket_class[ $module_class ]['tribe_for_event'];
			$event_ids[]     = (int) get_post_meta( $post_id, $tribe_for_event, true );

			return $event_ids;
		}


		// if rsvp or a ticket id get the connected id field
		$is_ticket_attendee = array_intersect( array( 'ticket', 'attendee' ), $services );
		if ( 'Tribe__Tickets__RSVP' === $module_class || $is_ticket_attendee ) {
			$event_ids[] = (int) get_post_meta( $post_id, $event_id_key, true );

			return $event_ids;
		}

		$ticket_cpt   = $this->ticket_class[ $module_class ]['ticket'];
		$order_id_key = $this->ticket_class[ $module_class ]['order_id_key'];

		if ( ! $order_id_key ) {
			return array();
		}

		$order_tickets = get_posts( array(
			'post_type'      => $ticket_cpt,
			'meta_key'       => $order_id_key,
			'meta_value'     => $post_id,
			'posts_per_page' => -1,
		) );

		foreach ( $order_tickets as $ticket ) {

			$event_id = get_post_meta( $ticket->ID, $event_id_key, true );

			if ( ! in_array( $event_id, $event_ids ) ) {
				$event_ids[] = (int) $event_id;
			}
		}

		return $event_ids;
	}