DROP function IF EXISTS `vn`.`entry_getCommission`;

DELIMITER $$
CREATE DEFINER=`root`@`%` FUNCTION `vn`.`entry_getCommission`(
    vTravelFk INT,
    vCurrencyFk INT,
    vSupplierFk INT
) RETURNS int(11)
    READS SQL DATA
BEGIN
    DECLARE vCommission INT;
    DECLARE vCurrentCommission INT;
    DECLARE vIsCurrencyUsd INT;
    
    SELECT count(*) INTO vIsCurrencyUsd
            FROM currency c
            WHERE c.code = 'USD' AND id = vCurrencyFk;
    
    IF NOT vIsCurrencyUsd THEN
        SELECT commission INTO vCurrentCommission
            FROM supplier s
            WHERE s.id = vSupplierFk;
        RETURN vCurrentCommission;
    END IF;

    SELECT ROUND(-100 * (1 - (1 / r.value))) INTO vCommission
        FROM travel t
            LEFT JOIN referenceCurrent r ON r.currencyFk = vCurrencyFk AND r.`dated` <= t.shipped
        WHERE t.id = vTravelFk
        ORDER BY r.`dated` DESC
        LIMIT 1;
        
    RETURN IFNULL(vCommission, 0);
END$$

DELIMITER ;