public static function event_discounts( $event_id ) {
		$orders            = self::get_orders( $event_id );
		$valid_order_items = self::get_valid_order_items_for_event( $event_id, $orders );

		$discounts = 0;

		foreach ( $valid_order_items as $order_id => $order ) {
			$item = $orders[ $order_id ];

			if ( 'cancelled' === $item['status']
			     || 'refunded' === $item['status']
			     || 'failed' === $item['status']
			) {
				continue;
			}

			foreach ( $order as $line_item ) {
				if ( self::item_has_discount( $line_item ) ) {
					$discounts += self::item_get_discount( $line_item );
				}
			}
		}

		return $discounts;
	}