+ PriceSnapshot

* Category commission inside a commission_rub field

store/migrations/0043_pricesnapshot_checklist_price_snapshot.py

@@ -0,0 +1,29 @@
+# Generated by Django 4.2.2 on 2023-10-04 02:53
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('store', '0042_oldchecklist_checklist_split_payment_proof_and_more'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PriceSnapshot',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('yuan_rate', models.DecimalField(decimal_places=2, default=0, max_digits=10, verbose_name='Курс CNY/RUB')),
+                ('delivery_price_CN', models.DecimalField(decimal_places=2, default=0, max_digits=10, verbose_name='Цена доставки по Китаю')),
+                ('delivery_price_CN_RU', models.DecimalField(decimal_places=2, default=0, max_digits=10, verbose_name='Цена доставки Китай-РФ')),
+                ('commission_rub', models.DecimalField(decimal_places=2, default=0, max_digits=10, verbose_name='Комиссия, руб')),
+            ],
+        ),
+        migrations.AddField(
+            model_name='checklist',
+            name='price_snapshot',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='checklist', to='store.pricesnapshot', verbose_name='Сохраненные цены'),
+        ),
+    ]

store/models.py

@@ -228,17 +228,23 @@ def generate_checklist_id():
 
 class ChecklistQuerySet(models.QuerySet):
     def with_base_related(self):
-        return self.select_related('manager', 'category', 'payment_method', 'promocode')\
+        return self.select_related('manager', 'category', 'payment_method', 'promocode', 'price_snapshot')\
             .prefetch_related(Prefetch('images', to_attr='_images'))
 
     def default_ordering(self):
         return self.order_by(F('status_updated_at').desc(nulls_last=True))
 
     def annotate_price_rub(self):
+        # FIXME: implement price_rub in DB query
+        return self
+
         yuan_rate = GlobalSettings.load().yuan_rate
         return self.annotate(_price_rub=F('price_yuan') * yuan_rate)
 
     def annotate_commission_rub(self):
+        # FIXME: implement category commission in DB query
+        return self
+
         commission = GlobalSettings.load().commission_rub
         return self.annotate(_commission_rub=Case(
             When(GreaterThan(F("_price_rub"), 150_000), then=F("_price_rub") * settings.COMMISSION_OVER_150K),
@@ -247,6 +253,13 @@ class ChecklistQuerySet(models.QuerySet):
         ))
 
 
+class PriceSnapshot(models.Model):
+    yuan_rate = models.DecimalField('Курс CNY/RUB', max_digits=10, decimal_places=2, default=0)
+    delivery_price_CN = models.DecimalField('Цена доставки по Китаю', max_digits=10, decimal_places=2, default=0)
+    delivery_price_CN_RU = models.DecimalField('Цена доставки Китай-РФ', max_digits=10, decimal_places=2, default=0)
+    commission_rub = models.DecimalField('Комиссия, руб', max_digits=10, decimal_places=2, default=0)
+
+
 @cleanup.select
 class Checklist(models.Model):
     # Statuses
@@ -350,6 +363,10 @@ class Checklist(models.Model):
     cdek_tracking = models.CharField('Трек-номер СДЭК', max_length=100, null=True, blank=True)
     cdek_barcode_pdf = models.FileField('Штрих-код СДЭК в PDF', upload_to='docs', null=True, blank=True)
 
+    price_snapshot = models.ForeignKey('PriceSnapshot', verbose_name='Сохраненные цены',
+                                       related_name='checklist',
+                                       on_delete=models.SET_NULL, null=True, blank=True)
+
     objects = ChecklistQuerySet.as_manager()
 
     class Meta:
@@ -368,11 +385,18 @@ class Checklist(models.Model):
 
     @property
     def price_rub(self) -> int:
-        # Prefer annotated field
+        # FIXME: implement price_rub in DB query
-        if hasattr(self, '_price_rub'):
+        # # Prefer annotated field for calculation
-            return self._price_rub
+        # if hasattr(self, '_price_rub'):
+        #     return self._price_rub
 
-        return math.ceil(GlobalSettings.load().yuan_rate * self.price_yuan)
+        # Get saved prices
+        if self.price_snapshot_id:
+            yuan_rate = self.price_snapshot.yuan_rate
+        else:
+            yuan_rate = GlobalSettings.load().yuan_rate
+
+        return math.ceil(yuan_rate * self.price_yuan)
 
     @property
     def full_price(self) -> int:
@@ -392,32 +416,58 @@ class Checklist(models.Model):
             no_comission = promocode.no_comission
 
         if not free_delivery:
-            price += GlobalSettings.load().delivery_price_CN + self.delivery_price_CN_RU
+            price += self.delivery_price_CN + self.delivery_price_CN_RU
 
         if not no_comission:
             price += self.commission_rub
 
-            # Add commission of bottom-most category
-            if self.category:
-                category = self.category.get_ancestors(ascending=True, include_self=True).first()
-                category_commission = getattr(category, 'commission', 0)
-                price += category_commission * self.price_rub / 100
-
         return max(0, math.ceil(price))
 
+    @property
+    def yuan_rate(self) -> Decimal:
+        # Get saved value if exists
+        if self.price_snapshot_id:
+            return self.price_snapshot.yuan_rate
+        else:
+            return GlobalSettings.load().yuan_rate
+
+    @property
+    def delivery_price_CN(self) -> Decimal:
+        # Get saved value if exists
+        if self.price_snapshot_id:
+            return self.price_snapshot.delivery_price_CN
+        else:
+            return GlobalSettings.load().delivery_price_CN
+
     @property
     def delivery_price_CN_RU(self) -> Decimal:
-        return getattr(self.category, 'delivery_price_CN_RU', Decimal(0))
+        # Get saved value if exists
+        if self.price_snapshot_id:
+            return self.price_snapshot.delivery_price_CN_RU
+        else:
+            return getattr(self.category, 'delivery_price_CN_RU', Decimal(0))
 
     @property
     def commission_rub(self) -> Decimal:
-        # Prefer annotated field
+        # FIXME: implement category commission in DB query
-        if hasattr(self, '_commission_rub'):
+        # # Prefer annotated field
-            return self._commission_rub
+        # if hasattr(self, '_commission_rub'):
+        #     return self._commission_rub
 
-        return (self.price_rub * Decimal(settings.COMMISSION_OVER_150K)
+        # Prefer saved value
-                if self.price_rub > 150_000
+        if self.price_snapshot_id:
-                else GlobalSettings.load().commission_rub)
+            return self.price_snapshot.commission_rub
+
+        commission = (self.price_rub * Decimal(settings.COMMISSION_OVER_150K)
+                      if self.price_rub > 150_000
+                      else GlobalSettings.load().commission_rub)
+
+        # Add commission of bottom-most category
+        if self.category_id:
+            category_commission = getattr(self.category, 'commission', 0)
+            commission += category_commission * self.price_rub / 100
+
+        return commission
 
     @property
     def preview_image(self):
@@ -467,9 +517,27 @@ class Checklist(models.Model):
 
         self.images.add(image_obj)
 
+    def save_prices(self):
+        # Temporarily remove snapshot from object
+        self.price_snapshot = None
+
+        snapshot, _ = PriceSnapshot.objects.get_or_create(
+            checklist__id=self.price_snapshot_id,
+            defaults={
+                'yuan_rate': self.yuan_rate,
+                'delivery_price_CN': self.delivery_price_CN,
+                'delivery_price_CN_RU': self.delivery_price_CN_RU,
+                'commission_rub': self.commission_rub,
+            }
+        )
+
+        # Restore snapshot
+        self.price_snapshot = snapshot
+
     def save(self, *args, **kwargs):
         if self.id:
             old_obj = Checklist.objects.filter(id=self.id).first()
+
             # If status was updated, update status_updated_at field
             if old_obj and self.status != old_obj.status:
                 self.status_updated_at = timezone.now()
@@ -485,5 +553,15 @@ class Checklist(models.Model):
             if not self.preview_image:
                 self.generate_preview()
 
+        # Save price details to snapshot
+        if self.price_snapshot_id:
+            # Status updated from other statuses back to DRAFT
+            if self.status == Checklist.Status.DRAFT:
+                self.price_snapshot.delete()
+                self.price_snapshot = None
+
+        elif self.status != Checklist.Status.DRAFT:
+            self.save_prices()
+
         super().save(*args, **kwargs)
 

store/serializers.py

@@ -75,16 +75,16 @@ class ChecklistSerializer(serializers.ModelSerializer):
     promo = serializers.SlugRelatedField(source='promocode', slug_field='name',
                                          queryset=Promocode.objects.active(), required=False, allow_null=True)
 
-    currency = serializers.SerializerMethodField('get_yuan_rate')
+    currency = serializers.DecimalField(source='yuan_rate', read_only=True, max_digits=10, decimal_places=2)
     curencycurency2 = serializers.DecimalField(source='price_yuan', required=False, max_digits=10, decimal_places=2)
     currency3 = serializers.IntegerField(source='price_rub', read_only=True)
-    chinadelivery = serializers.SerializerMethodField('get_delivery_price_CN', read_only=True)
+    chinadelivery = serializers.DecimalField(source='delivery_price_CN', read_only=True, max_digits=10, decimal_places=2)
-    chinadelivery2 = serializers.DecimalField(source='delivery_price_CN_RU', read_only=True, max_digits=10,
+    chinadelivery2 = serializers.DecimalField(source='delivery_price_CN_RU', read_only=True,
-                                              decimal_places=2)
+                                              max_digits=10, decimal_places=2)
     fullprice = serializers.IntegerField(source='full_price', read_only=True)
     realprice = serializers.DecimalField(source='real_price', required=False, allow_null=True, max_digits=10,
                                          decimal_places=2)
-    commission = serializers.SerializerMethodField('get_commission', read_only=True)
+    commission = serializers.DecimalField(source='commission_rub', read_only=True, max_digits=10, decimal_places=2)
 
     buyername = serializers.CharField(source='buyer_name', required=False, allow_null=True)
     buyerphone = serializers.CharField(source='buyer_phone', required=False, allow_null=True)
@@ -151,22 +151,10 @@ class ChecklistSerializer(serializers.ModelSerializer):
 
         return instance
 
-    @staticmethod
-    def get_yuan_rate(obj: Checklist):
-        return GlobalSettings.load().yuan_rate
-
     @staticmethod
     def get_image(obj: Checklist):
         return obj.images.all()
 
-    @staticmethod
-    def get_delivery_price_CN(obj: Checklist):
-        return GlobalSettings.load().delivery_price_CN
-
-    @staticmethod
-    def get_commission(obj: Checklist):
-        return GlobalSettings.load().commission_rub
-
     class Meta:
         model = Checklist
         fields = ('id', 'status', 'managerid', 'link',