# Shop Product Variation Link



DROP TRIGGER IF EXISTS before_insert_Shop_User_Basket;
DROP TRIGGER IF EXISTS before_update_Shop_User_Basket;


DELIMITER //
CREATE TRIGGER before_insert_Shop_User_Basket
BEFORE INSERT ON Shop_User_Basket
FOR EACH ROW
BEGIN
	SET NEW.created_on := IFNULL(NEW.created_on, NOW());
	SET NEW.created_by := IFNULL(NEW.created_by, IFNULL((SELECT id_user FROM Shop_User WHERE firstname = CURRENT_USER()), -1));
END //
DELIMITER ;


DELIMITER //
CREATE TRIGGER before_update_Shop_User_Basket
BEFORE UPDATE ON Shop_User_Basket
FOR EACH ROW
BEGIN
	IF NEW.id_change_set_user <=> OLD.id_change_set_user THEN
		SIGNAL SQLSTATE '45000'
        SET MESSAGE_TEXT = 'New change Set ID must be provided.';
    END IF;
    
    INSERT INTO Shop_User_Basket_Audit (
		id_item,
        name_field,
        value_prev,
        value_new,
        id_change_set_user
    )
    # Changed id_user
	SELECT NEW.id_item, 'id_user', OLD.id_user, NEW.id_user, NEW.id_change_set_user
		WHERE NOT OLD.id_user <=> NEW.id_user
	UNION
	# Changed id_product
	SELECT NEW.id_item, 'id_product', OLD.id_product, NEW.id_product, NEW.id_change_set_user
		WHERE NOT OLD.id_product <=> NEW.id_product
	UNION
	# Changed quantity
	SELECT NEW.id_item, 'quantity', CONVERT(OLD.quantity, CHAR), CONVERT(NEW.quantity, CHAR), NEW.id_change_set_user
		WHERE NOT (OLD.quantity <=> NEW.quantity)
	UNION
    # Changed active
	SELECT NEW.id_item, 'active', CONVERT(CONVERT(OLD.active, SIGNED), CHAR), CONVERT(CONVERT(NEW.active, SIGNED), CHAR), NEW.id_change_set_user
		WHERE NOT (OLD.active <=> NEW.active)
	;
END //
DELIMITER ;