feat: add SHOP_TAX_INCLUDED setting when prices already include tax

cartridge/shop/defaults.py

@@ -346,3 +346,11 @@
     editable=False,
     default=True,
 )
+
+register_setting(
+    name="SHOP_TAX_INCLUDED",
+    label=_("Tax included"),
+    description="The product prices are already including tax (boolean).",
+    editable=False,
+    default=False,
+)

cartridge/shop/models.py

@@ -532,7 +532,7 @@ def setup(self, request):
             self.total += self.shipping_total
         if self.discount_total is not None:
             self.total -= Decimal(self.discount_total)
-        if self.tax_total is not None:
+        if self.tax_total is not None and not settings.SHOP_TAX_INCLUDED:
             self.total += Decimal(self.tax_total)
         self.save()  # We need an ID before we can add related items.
         for item in request.cart:

cartridge/shop/templatetags/shop_tags.py

@@ -3,6 +3,7 @@
 from decimal import Decimal
 
 from django import template
+from mezzanine.conf import settings
 
 from cartridge.shop.utils import set_locale
 
@@ -60,7 +61,10 @@ def _order_totals(context):
         template_vars["order_total"] += Decimal(str(template_vars["shipping_total"]))
     if template_vars.get("discount_total", None) is not None:
         template_vars["order_total"] -= Decimal(str(template_vars["discount_total"]))
-    if template_vars.get("tax_total", None) is not None:
+    if (
+        template_vars.get("tax_total", None) is not None
+        and not settings.SHOP_TAX_INCLUDED
+    ):
         template_vars["order_total"] += Decimal(str(template_vars["tax_total"]))
     return template_vars