Dynamic bank currency (#2482)

* Add Currency model

* Bank currency rate from db

* Add currency choices

* Create currencies in migration

* Rename ue to currency_rate

conftest.py

@@ -6,6 +6,7 @@
     "apps.diplomas.factory",
     "apps.orders.factory",
     "apps.products.factory",
+    "apps.banking.factory",
     "core.factory",
 
     "apps.products.fixtures",

src/apps/banking/admin/__init__.py

@@ -0,0 +1,5 @@
+from apps.banking.admin.currency_rate import CurrencyRateAdmin
+
+__all__ = [
+    "CurrencyRateAdmin",
+]

src/apps/banking/admin/currency_rate.py

@@ -0,0 +1,32 @@
+from typing import Any
+
+from django.contrib.admin.models import CHANGE, LogEntry
+from django.http import HttpRequest
+
+from apps.banking.models import CurrencyRate
+from core.admin import ModelAdmin, admin
+from core.tasks import write_admin_log
+
+
+@admin.register(CurrencyRate)
+class CurrencyRateAdmin(ModelAdmin):
+    list_display = ["name", "rate"]
+
+    def get_object(self, request: HttpRequest, object_id: str, from_field: str | None = None) -> CurrencyRate | None:
+        obj = super().get_object(request, object_id, from_field)
+        if obj:
+            obj.__original_rate = obj.rate
+        return obj
+
+    def log_change(self, request: HttpRequest, obj: CurrencyRate, message: Any) -> LogEntry:
+        if obj.rate != obj.__original_rate:  # type: ignore[attr-defined]
+            return write_admin_log(
+                action_flag=CHANGE,
+                app="banking",
+                change_message=f"Currency rate was changed from {obj.__original_rate} to {obj.rate}",  # type: ignore[attr-defined]
+                model="CurrencyRate",
+                object_id=obj.id,
+                user_id=request.user.id,
+            )
+        else:
+            return super().log_change(request, obj, message)

src/apps/banking/base.py

@@ -7,6 +7,9 @@
 from django.conf import settings
 from django.utils.translation import gettext_lazy as _
 
+from apps.banking.exceptions import CurrencyRateDoesNotExist
+from apps.banking.models import CurrencyRate
+
 if TYPE_CHECKING:
     from django_stubs_ext import StrPromise
 
@@ -17,7 +20,6 @@
 class Bank(metaclass=ABCMeta):
     currency = "RUB"
     currency_symbol = "₽"
-    ue: Decimal = Decimal(1)  # ue stands for «условные единицы», this is some humour from 2000's
     acquiring_percent: Decimal = Decimal(0)  # we use it for analytics
     name: "StrPromise" = _("—")
 
@@ -67,6 +69,13 @@ def user(self) -> "User":
     def is_partial_refund_available(self) -> bool:
         return False
 
+    @classmethod
+    def get_currency_rate(cls) -> Decimal:
+        try:
+            return CurrencyRate.objects.get(name=cls.currency).rate
+        except CurrencyRate.DoesNotExist:
+            raise CurrencyRateDoesNotExist(f"Currency {cls.currency} is not supported")
+
     def get_formatted_amount(self, amount: Decimal) -> int:
         from apps.banking import price_calculator
 

src/apps/banking/exceptions.py

@@ -4,3 +4,7 @@ class BankException(Exception):
 
 class BankDoesNotExist(BankException):
     """Bank with given id does not exist."""
+
+
+class CurrencyRateDoesNotExist(BankException):
+    """Currency rate with given name does not exist."""

src/apps/banking/factory.py

@@ -0,0 +1,9 @@
+from typing import Any
+
+from apps.banking.models import CurrencyRate
+from core.test.factory import register
+
+
+@register
+def currency_rate(self: Any, **kwargs: dict[str, Any]) -> CurrencyRate:
+    return self.mixer.blend("banking.CurrencyRate", **kwargs)

src/apps/banking/migrations/0003_initial.py

@@ -0,0 +1,50 @@
+# Generated by Django 4.2.17 on 2024-12-24 18:15
+from decimal import Decimal
+
+from django.db import migrations, models
+
+import core.models
+
+
+def create_currencies(apps, schema_editor):
+    del schema_editor
+
+    CurrencyRate = apps.get_model("banking.CurrencyRate")
+
+    CurrencyRate.objects.create(name="RUB", rate=Decimal(1))
+    CurrencyRate.objects.create(name="USD", rate=Decimal(90))
+    CurrencyRate.objects.create(name="KZT", rate=Decimal("0.18"))
+    CurrencyRate.objects.create(name="KIS", rate=Decimal(1))
+
+
+class Migration(migrations.Migration):
+    initial = True
+
+    dependencies = [
+        ("banking", "0002_drop_recipient_model"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="CurrencyRate",
+            fields=[
+                ("id", models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name="ID")),
+                (
+                    "name",
+                    models.CharField(
+                        choices=[("RUB", "RUB"), ("USD", "USD"), ("KZT", "KZT"), ("KIS", "KIS (for zero-price orders)")],
+                        db_index=True,
+                        max_length=4,
+                        unique=True,
+                    ),
+                ),
+                ("rate", models.DecimalField(decimal_places=2, max_digits=6, verbose_name="Rate")),
+            ],
+            options={
+                "verbose_name": "Currency",
+                "verbose_name_plural": "Currencies",
+            },
+            bases=(core.models.TestUtilsMixin, models.Model),
+        ),
+        migrations.RunPython(create_currencies),
+    ]

src/apps/banking/models.py

@@ -0,0 +1,20 @@
+from django.db import models
+from django.db.models import TextChoices
+from django.utils.translation import gettext_lazy as _
+
+from core.models import DefaultModel
+
+
+class CurrencyRate(DefaultModel):
+    class Currency(TextChoices):
+        RUB = "RUB", _("RUB")
+        USD = "USD", _("USD")
+        KZT = "KZT", _("KZT")
+        KIS = "KIS", _("KIS (for zero-price orders)")
+
+    name = models.CharField(max_length=4, unique=True, choices=Currency.choices, db_index=True)
+    rate = models.DecimalField(max_digits=6, decimal_places=2, verbose_name=_("Rate"))
+
+    class Meta:
+        verbose_name = _("Currency")
+        verbose_name_plural = _("Currencies")

src/apps/banking/price_calculator.py

@@ -6,7 +6,7 @@
 
 def to_bank(bank: Type[Bank], price: Decimal) -> Decimal:
     """Get sum in bank currency"""
-    exchanged_price = Decimal(price) / Decimal(bank.ue)
+    exchanged_price = Decimal(price) / Decimal(bank.get_currency_rate())
 
     if not price % 1:  # initial price contains decimal part, e.g. kopecks
         exchanged_price = Decimal(round(exchanged_price))

src/apps/banking/tests/tests_get_currency_rate.py

@@ -0,0 +1,17 @@
+import pytest
+
+from apps.banking.base import Bank
+from apps.banking.exceptions import CurrencyRateDoesNotExist
+from apps.banking.models import CurrencyRate
+
+pytestmark = [pytest.mark.django_db]
+
+
+def test_get_currency_rate():
+    assert Bank.get_currency_rate() == 1
+
+
+def test_raise_if_no_currency_rate():
+    CurrencyRate.objects.all().delete()
+    with pytest.raises(CurrencyRateDoesNotExist):
+        Bank.get_currency_rate()

src/apps/banking/tests/tests_price_calculator.py

@@ -6,7 +6,7 @@
 
 
 @pytest.mark.parametrize(
-    ("price", "ue", "expected"),
+    ("price", "currency_rate", "expected"),
     [
         (100, 1, 100),
         (100.50, 1, 100.50),
@@ -21,9 +21,10 @@
         (100500.5, Decimal("0.17"), "591179.41"),
     ],
 )
-def test(price, ue, expected):
-    class MockBank: ...
-
-    MockBank.ue = ue
+def test(price, currency_rate, expected):
+    class MockBank:
+        @classmethod
+        def get_currency_rate(cls):
+            return currency_rate
 
     assert price_calculator.to_bank(MockBank, price) == Decimal(expected)

src/apps/orders/migrations/0039_alter_order_ue_rate.py

@@ -0,0 +1,17 @@
+# Generated by Django 4.2.17 on 2024-12-24 11:29
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("orders", "0038_alter_order_bank_id_alter_refund_bank_id"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="order",
+            name="ue_rate",
+            field=models.DecimalField(decimal_places=2, max_digits=6, verbose_name="Purchase-time UE rate"),
+        ),
+    ]

src/apps/orders/models/order.py

@@ -53,7 +53,7 @@ class Order(TimestampedModel):
     shipped = models.DateTimeField(_("Date when order was shipped"), null=True, blank=True)
 
     bank_id = models.CharField(_("User-requested bank string"), choices=BANK_CHOICES, blank=True, max_length=32)
-    ue_rate = models.IntegerField(_("Purchase-time UE rate"))
+    ue_rate = models.DecimalField(_("Purchase-time UE rate"), decimal_places=2, max_digits=6)
     acquiring_percent = models.DecimalField(default=0, max_digits=4, decimal_places=2)
 
     course = ItemField(to="products.Course", verbose_name=_("Course"), null=True, blank=True, on_delete=models.PROTECT)

src/apps/orders/services/order_creator.py

@@ -67,7 +67,7 @@ def create(self) -> Order:
             price=self.price,  # type: ignore
             promocode=self.promocode,
             bank_id=self.desired_bank,
-            ue_rate=self.bank.ue,
+            ue_rate=self.bank.get_currency_rate(),
             acquiring_percent=self.bank.acquiring_percent,
             analytics=self._parse_analytics(self.analytics),
         )

src/apps/orders/tests/orders/configurable_bank/conftest.py

@@ -51,11 +51,11 @@ def dolyame_bank(mocker):
 
 
 @pytest.fixture(autouse=True)
-def _freeze_ue_rate(mocker):
-    mocker.patch("apps.tinkoff.bank.TinkoffBank.ue", 11)
-    mocker.patch("apps.stripebank.bank.StripeBankUSD.ue", 33)
-    mocker.patch("apps.stripebank.bank.StripeBankKZT.ue", 33)
-    mocker.patch("apps.tinkoff.dolyame.Dolyame.ue", 44)
+def _freeze_currency_rate_rate(mocker):
+    mocker.patch("apps.tinkoff.bank.TinkoffBank.get_currency_rate", return_value=11)
+    mocker.patch("apps.stripebank.bank.StripeBankUSD.get_currency_rate", return_value=33)
+    mocker.patch("apps.stripebank.bank.StripeBankKZT.get_currency_rate", return_value=33)
+    mocker.patch("apps.tinkoff.dolyame.Dolyame.get_currency_rate", return_value=44)
 
 
 @pytest.fixture(autouse=True)

src/apps/orders/tests/orders/configurable_bank/tests_configurable_bank.py

@@ -60,7 +60,7 @@ def test_desired_bank_is_saved(call_purchase, bank):
         ("dolyame", 44),
     ],
 )
-def test_ue_rate_is_saved(call_purchase, bank, ue_rate):
+def test_currency_rate_rate_is_saved(call_purchase, bank, ue_rate):
     call_purchase(desired_bank=bank)
 
     order = Order.objects.last()

src/apps/orders/tests/orders/promocode/tests_price_with_promocode.py

@@ -10,12 +10,12 @@
 
 @pytest.fixture(autouse=True)
 def _freeze_stripe_course(mocker):
-    mocker.patch("apps.stripebank.bank.StripeBankUSD.ue", Decimal(70))  # let it be forever :'(
+    mocker.patch("apps.stripebank.bank.StripeBankUSD.get_currency_rate", return_value=Decimal(70))  # let it be forever :'(
 
 
 @pytest.fixture(autouse=True)
 def _freeze_stripe_kz_course(mocker):
-    mocker.patch("apps.stripebank.bank.StripeBankKZT.ue", Decimal("0.18"))
+    mocker.patch("apps.stripebank.bank.StripeBankKZT.get_currency_rate", return_value=Decimal("0.18"))
 
 
 @pytest.mark.parametrize(

src/apps/orders/tests/orders/services/tests_order_refunder.py

@@ -35,8 +35,8 @@ def _adjust_settings(settings, mocker):
         "[email protected]",
         "[email protected]",
     ]
-    mocker.patch("apps.stripebank.bank.StripeBankUSD.ue", Decimal(80))
-    mocker.patch("apps.stripebank.bank.StripeBankKZT.ue", Decimal("0.18"))
+    mocker.patch("apps.stripebank.bank.StripeBankUSD.get_currency_rate", return_value=Decimal(80))
+    mocker.patch("apps.stripebank.bank.StripeBankKZT.get_currency_rate", return_value=Decimal("0.18"))
 
 
 @pytest.fixture
@@ -66,7 +66,6 @@ def mock_stripe_refund(mocker):
 
 @pytest.fixture
 def mock_stripe_kz_refund(mocker):
-    mocker.patch("apps.stripebank.bank.StripeBankUSD.ue", 70)
     return mocker.patch("apps.stripebank.bank.StripeBankKZT.refund")
 
 

src/apps/stripebank/bank.py

@@ -63,7 +63,6 @@ def get_items(self) -> list[dict[str, Any]]:
 
 
 class StripeBankUSD(BaseStripeBank):
-    ue = Decimal(90)
     currency = "USD"
     currency_symbol = "$"
     name = _("Stripe USD")
@@ -72,7 +71,6 @@ class StripeBankUSD(BaseStripeBank):
 
 
 class StripeBankKZT(BaseStripeBank):
-    ue = Decimal("0.18")
     currency = "KZT"
     currency_symbol = "₸"
     name = _("Stripe KZT")

src/apps/stripebank/tests/stripebank/conftest.py

@@ -17,7 +17,7 @@ def stripe(order):
 
 @pytest.fixture(autouse=True)
 def _fix_stripe_course(mocker):
-    mocker.patch("apps.stripebank.bank.BaseStripeBank.ue", 70)  # let it be forever :'(
+    mocker.patch("apps.stripebank.bank.BaseStripeBank.get_currency_rate", return_value=70)  # let it be forever :'(
 
 
 @pytest.fixture

src/apps/stripebank/webhook_handler.py

@@ -77,4 +77,4 @@ def charge_refunded(self, webhook_event: stripe.Event) -> None:
         )
 
     def convert_amount(self, stripe_amount: int) -> Decimal:
-        return Decimal(stripe_amount) / 100 * self.bank.ue
+        return Decimal(stripe_amount) / 100 * self.bank.get_currency_rate()

src/apps/tinkoff/tests/tinkoff/payment_notifications/tests_tinkoff_token_validator.py

@@ -3,6 +3,10 @@
 from apps.tinkoff.exceptions import TinkoffPaymentNotificationInvalidToken, TinkoffPaymentNotificationNoTokenPassed
 from apps.tinkoff.token_validator import TinkoffNotificationsTokenValidator
 
+pytestmark = [
+    pytest.mark.django_db,
+]
+
 
 @pytest.mark.parametrize(
     "payload",

src/core/tasks/write_admin_log.py

@@ -13,12 +13,12 @@ def write_admin_log(
     model: str,
     object_id: int,
     user_id: int,
-) -> None:
+) -> LogEntry:
     content_type_id = ContentType.objects.get(app_label=app, model=model.lower()).id
 
     obj = apps.get_model(app, model).objects.get(id=object_id)
 
-    LogEntry.objects.log_action(
+    return LogEntry.objects.log_action(
         action_flag=action_flag,
         change_message=change_message,
         content_type_id=content_type_id,