Fix: Edge cases where rounding due to changed quantities in printing was altering the final amount in decimals, at times resulted in final rounding to change up or down.

barker/barker/models/inventory.py

@@ -52,16 +52,24 @@ class Inventory(Base):
         tax_id,
         tax_rate,
         sort_order,
+        product=None,
+        tax=None,
     ):
         self.kot_id = kot_id
-        self.product_id = product_id
+        if product_id is not None:
+            self.product_id = product_id
         self.quantity = quantity
         self.price = price
         self.discount = discount
         self.is_happy_hour = is_hh
-        self.tax_id = tax_id
+        if tax_id is not None:
+            self.tax_id = tax_id
         self.tax_rate = tax_rate
         self.sort_order = sort_order
+        if product is not None:
+            self.product = product
+        if tax is not None:
+            self.tax = tax
 
     @hybrid_property
     def effective_price(self):

barker/barker/printing/bill.py

@@ -45,9 +45,20 @@ def print_bill(voucher_id: uuid.UUID, db: Session):
         )
         if key in items_dict:
             items_dict[key].quantity += i.quantity
-            i.quantity = 0
         else:
-            items_dict[key] = i
+            items_dict[key] = Inventory(
+                None,
+                i.product_id,
+                i.quantity,
+                i.price,
+                i.discount,
+                i.is_happy_hour,
+                None,
+                i.tax_rate,
+                0,
+                i.product,
+                i.tax,
+            )
 
     for i in [it for it in items_dict.values() if it.quantity != 0]:
         get_tax_item(i.tax.id, i.tax.name, i.tax_amount, tax)
@@ -132,14 +143,14 @@ def design_bill(
     s += "\n\r" + "------------------------------------------"
 
     # Totals
-    amount = sum(i.quantity * i.price for i in items)
+    amount = sum(round(i.quantity * i.price, 2) for i in items)
     s += f"\n\r{'Subtotal :': >32} {currency_format(amount): >9}"
 
-    amount = sum(i.quantity * i.price for i in items if i.is_happy_hour)
+    amount = sum(round(i.quantity * i.price, 2) for i in items if i.is_happy_hour)
     if amount != 0:
         s += f"\n\r{'Happy Hour Discount :': >32} {currency_format(amount): >9}"
 
-    amount = sum(i.quantity * i.effective_price * i.discount for i in items)
+    amount = sum(round(i.quantity * i.effective_price * i.discount, 2) for i in items)
     if amount != 0:
         s += f"\n\r{'Discount :': >32} {currency_format(amount): >9}"