Adding internal functions to use internal prices

InvenTree/common/models.py

@@ -726,7 +726,7 @@ class PriceBreak(models.Model):
         return converted.amount
 
 
-def get_price(instance, quantity, moq=True, multiples=True, currency=None):
+def get_price(instance, quantity, moq=True, multiples=True, currency=None, break_name:str='price_breaks'):
     """ Calculate the price based on quantity price breaks.
 
     - Don't forget to add in flat-fee cost (base_cost field)
@@ -734,7 +734,10 @@ def get_price(instance, quantity, moq=True, multiples=True, currency=None):
     - If order multiples are to be observed, then we need to calculate based on that, too
     """
 
-    price_breaks = instance.price_breaks.all()
+    if hasattr(instance, break_name):
+        price_breaks = getattr(instance, break_name).all()
+    else:
+        price_breaks = []
 
     # No price break information available?
     if len(price_breaks) == 0:
@@ -756,7 +759,7 @@ def get_price(instance, quantity, moq=True, multiples=True, currency=None):
         currency = currency_code_default()
 
     pb_min = None
-    for pb in instance.price_breaks.all():
+    for pb in price_breaks:
         # Store smallest price break
         if not pb_min:
             pb_min = pb