split add-item in add-item and update-item in inventory

1 files changed, 13 insertions, 11 deletions

diff --git a/src/inventory.lisp b/src/inventory.lisp
index 429f666..657585e 100644
--- a/src/inventory.lisp
+++ b/src/inventory.lisp
@@ -34,22 +34,24 @@
 	(setq items (remove item items))
 	(setq filled (- filled (cdr item)))))
 
+(defmethod update-item ((inv inventory) item qty old-item old-qty)
+  (with-slots (filled items) inv
+	(delete-item inv (cons old-item old-qty))
+	(let ((total-quantity (+ qty old-qty)))
+	  (push (cons item total-quantity) items)
+	  (setq filled (+ filled total-quantity)))))
+
 (defmethod add-item ((inv inventory) item quantity)
   ;; add <quantity> of <item> to inventory
   (when (> quantity 0)
 	(with-slots (size filled items) inv
 	  (when (> size (+ filled quantity))
-		(let* ((old-item
-				(find-item inv (commodities:name item)))
-			   (qt
-				(if old-item
-					(progn
-					  (delete-item inv old-item)
-					  (+ quantity (cdr old-item)))
-					quantity)))
-		  (prog1 (setq filled (+ filled qt))
-			(push (cons item qt)
-				  items)))))))
+		(let ((old-item (find-item inv (commodities:name item))))
+		  (if old-item
+			  (update-item inv item quantity
+						   (car old-item) (cdr old-item))
+			  (prog1 (setq filled (+ filled quantity))
+				(push (cons item quantity) items))))))))
 
 (defmethod remove-item ((inv inventory) name quantity)
   ;; remove <quantity> of <item> from inventory