USE fetchmetrics;

DROP TRIGGER IF EXISTS fetchmetrics.before_insert_DOG_User_Company_Link;
DROP TRIGGER IF EXISTS fetchmetrics.before_update_DOG_User_Company_Link;


DELIMITER //
CREATE TRIGGER fetchmetrics.before_insert_DOG_User_Company_Link
BEFORE INSERT ON fetchmetrics.DOG_User_Company_Link
FOR EACH ROW
BEGIN
	SET NEW.created_on := IFNULL(NEW.created_on, NOW());
END //
DELIMITER ;


DELIMITER //
CREATE TRIGGER fetchmetrics.before_update_DOG_User_Company_Link
BEFORE UPDATE ON fetchmetrics.DOG_User_Company_Link
FOR EACH ROW
BEGIN
	IF OLD.id_change_set <=> NEW.id_change_set THEN
		SIGNAL SQLSTATE '45000'
        SET MESSAGE_TEXT = 'New change Set ID must be provided.';
    END IF;
    
    INSERT INTO fetchmetrics.DOG_User_Company_Link_Audit (
		id_link,
        name_field,
        value_prev,
        value_new,
        id_change_set
    )
    -- Changed id_user
	SELECT NEW.id_link, 'id_user', CONVERT(OLD.id_user, CHAR), CONVERT(NEW.id_user, CHAR), NEW.id_change_set
		WHERE NOT OLD.id_user <=> NEW.id_user
    UNION
    -- Changed id_company
	SELECT NEW.id_link, 'id_company', CONVERT(OLD.id_company, CHAR), CONVERT(NEW.id_company, CHAR), NEW.id_change_set
		WHERE NOT OLD.id_company <=> NEW.id_company
    UNION
	-- Changed active
	SELECT NEW.id_link, 'active', CONVERT(CONVERT(OLD.active, SIGNED), CHAR), CONVERT(CONVERT(NEW.active, SIGNED), CHAR), NEW.id_change_set
		WHERE NOT (OLD.active <=> NEW.active)
    ;
END //
DELIMITER ;