class ProductDetailSerializer(serializers.ModelSerializer):
    group = ProductGroupSerializer()
    product_group = serializers.SerializerMethodField()
    product_characteristic = serializers.SerializerMethodField()
    gallery = GallerySerializer(many=True)
    size_variant = ProductSizeVariantSerializer(many=True)
    color = ProductColorSerializer()
    test = serializers.SerializerMethodField()

    class Meta:
        model = Product
        fields = (
            'id', 'name', 'slug', 'image', 'description', 'group', 'product_characteristic',
            'size_variant', 'gallery', 'color', 'product_group', 'test'
        )

    def get_test(self, instance):
        return ProductListSerializer(instance.recommended_product.all().with_min_price(), many=True)

    def get_product_group(self, instance):
        return ProductListGroupSerializer(
            instance.group.product.all().exclude(slug=instance.slug).select_related('color').distinct(),
            many=True,
            context=self.context
        ).data

    def get_product_characteristic(self, instance):
        all_characteristics = ProductCharacteristic.objects\
            .filter(product__id=instance.id, characteristic__isnull=False, value__isnull=False)\
            .select_related('product', 'characteristic', 'value')
        return ProductCharacteristicSerializer(all_characteristics, many=True).data