rateing system

backend/product/serializers.py

@@ -158,6 +158,7 @@ class DynamicProductSerializer(serializers.ModelSerializer):
     main_image = serializers.SerializerMethodField()
     customer_pickup_title = serializers.SerializerMethodField()
     customer_pickup_description = serializers.SerializerMethodField()
+    average_rating = serializers.SerializerMethodField()
     
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -174,9 +175,9 @@ class DynamicProductSerializer(serializers.ModelSerializer):
         model = ProductModel
         fields = "__all__"
         view_type = {
-            'list': ['id', 'name', 'rating', 'slug', 'category',  'colors', 'image', 'best_deal_price_before_discount', 'best_deal_price_after_discount', 'best_deal_discount', 'main_image'],
-            'slider': ['id', 'name', 'rating', 'slug', 'category', 'variants', 'colors', 'image', 'best_deal_price_before_discount', 'best_deal_price_after_discount', 'best_deal_discount', ],
-            'instance': ['id', 'name', 'description', 'rating',  'slug', 'meta_description', 'meta_keywords', 'meta_rating', 'category', 'related_products', 'in_pack_items', 'variants', 'colors', 'added_to_favorites', 'image', 'customer_pickup_title', 'customer_pickup_description'],
+            'list': ['id', 'name', 'rating', 'slug', 'category',  'colors', 'image', 'best_deal_price_before_discount', 'best_deal_price_after_discount', 'best_deal_discount', 'main_image', 'average_rating'],
+            'slider': ['id', 'name', 'rating', 'slug', 'category', 'variants', 'colors', 'image', 'best_deal_price_before_discount', 'best_deal_price_after_discount', 'best_deal_discount', 'average_rating'],
+            'instance': ['id', 'name', 'description', 'rating',  'slug', 'meta_description', 'meta_keywords', 'meta_rating', 'category', 'related_products', 'in_pack_items', 'variants', 'colors', 'added_to_favorites', 'image', 'customer_pickup_title', 'customer_pickup_description', 'average_rating'],
             'chat': ['id', 'name', 'description', 'variants', 'image']
         }
 
@@ -241,6 +242,39 @@ class DynamicProductSerializer(serializers.ModelSerializer):
         # Use exists() with filter instead of fetching all products
         return UserFavorites.objects.filter(user=request.user, products=obj).exists()
 
+    def get_average_rating(self, obj):
+        """Get cached average rating for product - optimized with prefetch"""
+        from django.core.cache import cache
+        from django.db.models import Avg
+        
+        cache_key = f'product_avg_rating_{obj.id}'
+        avg_rating = cache.get(cache_key)
+        
+        if avg_rating is None:
+            # Try to use prefetched ratings if available (no query needed)
+            try:
+                prefetched_ratings = obj._prefetched_objects_cache.get('ratings')
+                if prefetched_ratings is not None:
+                    # Use prefetched data - no database query
+                    ratings_list = [r.rating for r in prefetched_ratings]
+                    if ratings_list:
+                        avg_rating = round(sum(ratings_list) / len(ratings_list), 2)
+                    else:
+                        avg_rating = 0
+                else:
+                    # Fall back to aggregation query if not prefetched
+                    avg_rating = obj.ratings.aggregate(Avg('rating'))['rating__avg'] or 0
+                    avg_rating = round(avg_rating, 2)
+            except (AttributeError, KeyError):
+                # Fall back to aggregation query
+                avg_rating = obj.ratings.aggregate(Avg('rating'))['rating__avg'] or 0
+                avg_rating = round(avg_rating, 2)
+            
+            # Cache for 1 hour
+            cache.set(cache_key, avg_rating, 3600)
+        
+        return avg_rating
+
     def get_variants(self, obj):
         view_type = self.context.get('view_type')
         if view_type == 'slider':
@@ -292,3 +326,25 @@ class BotProductSerializer(serializers.ModelSerializer):
             'pk',
             'name'
         ]
+
+
+class ProductRatingSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ProductRating
+        fields = ['rating']
+    
+    def validate_rating(self, value):
+        if value not in [1, 2, 3, 4, 5]:
+            raise serializers.ValidationError("امتیاز باید بین 1 تا 5 باشد")
+        return value
+    
+    def create(self, validated_data):
+        product_id = self.context.get('product_id')
+        user = self.context.get('request').user
+        
+        rating = ProductRating.objects.create(
+            product_id=product_id,
+            user=user,
+            rating=validated_data['rating']
+        )
+        return rating