solved errors that happened during tests

2 files changed, 27 insertions, 9 deletions

diff --git a/src/commodities.lisp b/src/commodities.lisp
index 1302a98..6f8c65d 100644
--- a/src/commodities.lisp
+++ b/src/commodities.lisp
@@ -2,7 +2,8 @@
   (:use :cl)
   (:export :new-commodity
 		   :name
-		   :price))
+		   :price
+		   :commodity-eq))
 
 (in-package :commodities)
 
@@ -17,3 +18,12 @@
 	(make-instance 'commodity
 				   :name name
 				   :price price)))
+
+(defmethod print-object ((object commodity) stream)
+  (print-unreadable-object (object stream :type t)
+	(with-slots (name price) object
+	  (format stream "~a worth ~a" name price))))
+
+(defmethod commodity-eq ((c1 commodity) (c2 commodity))
+  (and (equal (name c1) (name c2))
+	   (= (price c1) (price c2))))
diff --git a/src/inventory.lisp b/src/inventory.lisp
index 657585e..e122364 100644
--- a/src/inventory.lisp
+++ b/src/inventory.lisp
@@ -34,22 +34,30 @@
 	(setq items (remove item items))
 	(setq filled (- filled (cdr item)))))
 
-(defmethod update-item ((inv inventory) item qty old-item old-qty)
+(defmethod update-item ((inv inventory) item qty old-item)
   (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)))))
+	(delete-item inv old-item)
+	(let ((total-quantity (+ qty (cdr old-item)))
+		  (item-name (commodities:name item))
+		  (item-price (commodities:price item))
+		  (old-qty (cdr old-item))
+		  (old-item-price (commodities:price (car old-item))))
+	  (let ((new-item (commodities:new-commodity item-name
+												 (/ (+ (* qty item-price) (* old-qty old-item-price))
+													total-quantity))))
+		(push (cons
+			   new-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))
+	  (when (>= size (+ filled quantity))
 		(let ((old-item (find-item inv (commodities:name item))))
 		  (if old-item
-			  (update-item inv item quantity
-						   (car old-item) (cdr old-item))
+			  (update-item inv item quantity old-item)
 			  (prog1 (setq filled (+ filled quantity))
 				(push (cons item quantity) items))))))))