Enforce product limits in user shop

code/moya-web/src/main/java/fi/codecrew/moya/web/helper/ProductShopItemHelper.java

@@ -46,7 +46,7 @@ public class ProductShopItemHelper extends GenericCDIView {
 	public void updateProductShopItemCount(ProductShopItem item) {
 
 		// Discounts or overridden price, you cannot get both
-        if(item.isOverrideUnitPrice()) {
+		if (item.isOverrideUnitPrice()) {
 			item.setInternalPrice(item.getOverriddenUnitPrice().multiply(item.getCount()));
 		} else {
 			item.setInternalPrice(item.getProduct().getPrice().abs().multiply(item.getCount()));
@@ -63,7 +63,6 @@ public class ProductShopItemHelper extends GenericCDIView {
 			}
 		}
 
-
 	}
 
 	public void setProductShopItemCount(ProductShopItem item, BigDecimal count) {
@@ -78,10 +77,13 @@ public class ProductShopItemHelper extends GenericCDIView {
 	}
 
 	public boolean updateProductShopItemLimit(ProductShopItem item, BigDecimal limitValue) {
+		BigDecimal productsLeft = null;
 
-		if (limitValue != null && limitValue.compareTo(BigDecimal.ZERO) < 0)
-		{
-			this.setProductShopItemCount(item, item.getCount().add(limitValue));
+		if (limitValue != null) {
+			productsLeft = limitValue.subtract(item.getCount());
+			if (productsLeft.compareTo(BigDecimal.ZERO) < 0) {
+
+				this.setProductShopItemCount(item, limitValue);
 
 				if (item.getCount().compareTo(BigDecimal.ZERO) < 0) {
 					this.setProductShopItemCount(item, BigDecimal.ZERO);
@@ -89,8 +91,8 @@ public class ProductShopItemHelper extends GenericCDIView {
 				item.setLimit(BigDecimal.ZERO);
 				return true;
 			}
-		item.setLimit(limitValue);
+		}
+		item.setLimit(productsLeft);
 		return false;
 	}
-
 }