feat(models/serializers): migrate to Decimal for monetary values

Replaced `float` with `Decimal` for monetary calculations to prevent precision loss and enhance accuracy. Updated related models, serializers, and utility functions accordingly.

engine/core/models.py

@@ -469,21 +469,21 @@ class Category(NiceModel, MPTTModel):
         ).distinct()
 
     @cached_property
-    def min_price(self) -> float:
+    def min_price(self) -> Decimal:
         return (
             self.products.filter(is_active=True, stocks__is_active=True).aggregate(
                 Min("stocks__price")
             )["stocks__price__min"]
-            or 0.0
+            or Decimal("0.00")
         )
 
     @cached_property
-    def max_price(self) -> float:
+    def max_price(self) -> Decimal:
         return (
             self.products.filter(is_active=True, stocks__is_active=True).aggregate(
                 Max("stocks__price")
             )["stocks__price__max"]
-            or 0.0
+            or Decimal("0.00")
         )
 
     @cached_property
@@ -776,7 +776,7 @@ class Product(NiceModel):
         ).order_by("-discount_percent")
 
     @cached_property
-    def discount_price(self) -> float | None:
+    def discount_price(self) -> Decimal | None:
         promo = self.promos.first()
         return (self.price / 100) * promo.discount_percent if promo else None
 
@@ -795,11 +795,11 @@ class Product(NiceModel):
         return Feedback.objects.filter(order_product__product_id=self.pk).count()
 
     @property
-    def price(self: Self) -> float:
+    def price(self: Self) -> Decimal:
         stock = (
             self.stocks.filter(is_active=True).only("price").order_by("-price").first()
         )
-        return round(stock.price, 2) if stock else 0.0
+        return Decimal(round(stock.price, 2)) if stock else Decimal("0.00")
 
     @cached_property
     def quantity(self) -> int:

engine/core/serializers/detail.py

@@ -3,7 +3,7 @@ from contextlib import suppress
 from typing import Any
 
 from drf_spectacular.utils import extend_schema_field
-from rest_framework.fields import JSONField, SerializerMethodField
+from rest_framework.fields import DecimalField, JSONField, SerializerMethodField
 from rest_framework.serializers import ListSerializer, ModelSerializer
 from rest_framework_recursive.fields import RecursiveField
 
@@ -64,8 +64,12 @@ class CategoryDetailSerializer(ModelSerializer):
     description = SerializerMethodField()
     filterable_attributes = SerializerMethodField()
     brands = BrandSimpleSerializer(many=True, read_only=True)
-    min_price = SerializerMethodField()
+    min_price = DecimalField(
-    max_price = SerializerMethodField()
+        max_digits=12, decimal_places=2, read_only=True, coerce_to_string=False
+    )
+    max_price = DecimalField(
+        max_digits=12, decimal_places=2, read_only=True, coerce_to_string=False
+    )
 
     class Meta:
         model = Category
@@ -107,11 +111,6 @@ class CategoryDetailSerializer(ModelSerializer):
             return list(serializer.data)
         return []
 
-    def get_min_price(self, obj: Category) -> float:
-        return obj.min_price
-
-    def get_max_price(self, obj: Category) -> float:
-        return obj.max_price
 
 
 class BrandDetailSerializer(ModelSerializer):
@@ -281,10 +280,15 @@ class ProductDetailSerializer(ModelSerializer):
 
     description = SerializerMethodField()
     rating = SerializerMethodField()
-    price = SerializerMethodField()
+    price = DecimalField(
+        max_digits=12, decimal_places=2, read_only=True, coerce_to_string=False
+    )
     quantity = SerializerMethodField()
     feedbacks_count = SerializerMethodField()
-    discount_price = SerializerMethodField()
+    discount_price = DecimalField(
+        max_digits=12, decimal_places=2, read_only=True, allow_null=True,
+        coerce_to_string=False,
+    )
     personal_orders_only = SerializerMethodField()
 
     class Meta:
@@ -319,9 +323,6 @@ class ProductDetailSerializer(ModelSerializer):
     def get_rating(self, obj: Product) -> float:
         return obj.rating
 
-    def get_price(self, obj: Product) -> float:
-        return obj.price
-
     def get_feedbacks_count(self, obj: Product) -> int:
         return obj.feedbacks_count
 
@@ -331,9 +332,6 @@ class ProductDetailSerializer(ModelSerializer):
     def get_quantity(self, obj: Product) -> int:
         return obj.quantity
 
-    def get_discount_price(self, obj: Product) -> float | None:
-        return obj.discount_price
-
 
 class PromotionDetailSerializer(ModelSerializer):
     products = ProductDetailSerializer(
@@ -416,7 +414,9 @@ class OrderDetailSerializer(ModelSerializer):
     order_products = OrderProductDetailSerializer(
         many=True,
     )
-    total_price = SerializerMethodField(read_only=True)
+    total_price = DecimalField(
+        max_digits=12, decimal_places=2, read_only=True, coerce_to_string=False
+    )
 
     class Meta:
         model = Order
@@ -433,6 +433,3 @@ class OrderDetailSerializer(ModelSerializer):
             "created",
             "modified",
         ]
-
-    def get_total_price(self, obj: Order) -> float:
-        return obj.total_price  # ty: ignore[invalid-return-type]

engine/core/serializers/simple.py

@@ -1,6 +1,6 @@
 from typing import Any
 
-from rest_framework.fields import JSONField, SerializerMethodField
+from rest_framework.fields import DecimalField, JSONField, SerializerMethodField
 from rest_framework.relations import PrimaryKeyRelatedField
 from rest_framework.serializers import ModelSerializer
 
@@ -140,11 +140,16 @@ class ProductSimpleSerializer(ModelSerializer):
 
     description = SerializerMethodField()
     rating = SerializerMethodField()
-    price = SerializerMethodField()
+    price = DecimalField(
+        max_digits=12, decimal_places=2, read_only=True, coerce_to_string=False
+    )
     quantity = SerializerMethodField()
     feedbacks_count = SerializerMethodField()
     personal_orders_only = SerializerMethodField()
-    discount_price = SerializerMethodField()
+    discount_price = DecimalField(
+        max_digits=12, decimal_places=2, read_only=True, allow_null=True,
+        coerce_to_string=False,
+    )
 
     class Meta:
         model = Product
@@ -176,9 +181,6 @@ class ProductSimpleSerializer(ModelSerializer):
     def get_rating(self, obj: Product) -> float:
         return obj.rating
 
-    def get_price(self, obj: Product) -> float:
-        return obj.price
-
     def get_feedbacks_count(self, obj: Product) -> int:
         return obj.feedbacks_count
 
@@ -188,9 +190,6 @@ class ProductSimpleSerializer(ModelSerializer):
     def get_personal_orders_only(self, obj: Product) -> bool:
         return obj.personal_orders_only
 
-    def get_discount_price(self, obj: Product) -> float | None:
-        return obj.discount_price
-
 
 class VendorSimpleSerializer(ModelSerializer):
     class Meta:
@@ -286,7 +285,9 @@ class OrderSimpleSerializer(ModelSerializer):
     billing_address = AddressSerializer(read_only=True, required=False)
     shipping_address = AddressSerializer(read_only=True, required=False)
     attributes = JSONField(required=False)
-    total_price = SerializerMethodField(read_only=True)
+    total_price = DecimalField(
+        max_digits=12, decimal_places=2, read_only=True, coerce_to_string=False
+    )
 
     class Meta:
         model = Order
@@ -305,6 +306,3 @@ class OrderSimpleSerializer(ModelSerializer):
             "created",
             "modified",
         ]
-
-    def get_total_price(self, obj: Order) -> float:
-        return obj.total_price  # ty: ignore[invalid-return-type]

engine/core/utils/seo_builders.py

@@ -56,7 +56,7 @@ def product_schema(product, images, rating=None):
         offers.append(
             {
                 "@type": "Offer",
-                "price": round(stock.price, 2),
+                "price": float(round(stock.price, 2)),
                 "priceCurrency": settings.CURRENCY_CODE,
                 "availability": "https://schema.org/InStock"
                 if stock.quantity > 0

engine/core/views.py

@@ -135,6 +135,22 @@ class CustomGraphQLView(FileUploadGraphQLView):
     def get_context(self, request):
         return request
 
+    @staticmethod
+    def json_encode(request, d, pretty=False):
+        from decimal import Decimal
+
+        import orjson
+
+        def _default(obj):
+            if isinstance(obj, Decimal):
+                return float(obj)
+            raise TypeError(f"Object of type {type(obj).__name__} is not JSON serializable")
+
+        opts = orjson.OPT_NON_STR_KEYS
+        if pretty or request.GET.get("pretty"):
+            opts |= orjson.OPT_INDENT_2 | orjson.OPT_SORT_KEYS
+        return orjson.dumps(d, default=_default, option=opts).decode("utf-8")
+
 
 @extend_schema_view(**CUSTOM_OPENAPI_SCHEMA)
 class CustomSpectacularAPIView(SpectacularAPIView):