Implement auto-renew subscription feature and enhance payment method handling

- Added a recurring billing task to automatically charge users one day before subscription expiry, improving subscription management.
- Introduced a new UserBilling model to store saved payment methods for off-session charges, enhancing user experience.
- Updated YooKassa service to support saving payment methods and capturing payments for auto-renewals.
- Enhanced subscription handling to toggle auto-renew settings and provide user feedback through localized messages.
- Improved error handling and logging for payment method persistence and subscription renewal processes.

db/dal/subscription_dal.py

@@ -53,6 +53,11 @@ async def update_subscription(
     return sub
 
 
+async def set_auto_renew(session: AsyncSession, subscription_id: int, enabled: bool) -> Optional[Subscription]:
+    """Toggle auto_renew_enabled for a subscription."""
+    return await update_subscription(session, subscription_id, {"auto_renew_enabled": enabled})
+
+
 async def set_user_subscriptions_cancelled_with_grace(
         session: AsyncSession, user_id: int, grace_days: int = 1) -> int:
     """Mark all active user subscriptions as cancelled with a short grace period.

db/dal/user_billing_dal.py

@@ -0,0 +1,41 @@
+from typing import Optional, Dict, Any
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select, update
+from sqlalchemy.sql import func
+
+from db.models import UserBilling
+
+
+async def get_user_billing(session: AsyncSession, user_id: int) -> Optional[UserBilling]:
+    stmt = select(UserBilling).where(UserBilling.user_id == user_id)
+    result = await session.execute(stmt)
+    return result.scalar_one_or_none()
+
+
+async def upsert_yk_payment_method(
+    session: AsyncSession,
+    *,
+    user_id: int,
+    payment_method_id: str,
+    card_last4: Optional[str] = None,
+    card_network: Optional[str] = None,
+) -> UserBilling:
+    existing = await get_user_billing(session, user_id)
+    if existing:
+        existing.yookassa_payment_method_id = payment_method_id
+        existing.card_last4 = card_last4
+        existing.card_network = card_network
+        existing.updated_at = func.now()
+        await session.flush()
+        await session.refresh(existing)
+        return existing
+    record = UserBilling(
+        user_id=user_id,
+        yookassa_payment_method_id=payment_method_id,
+        card_last4=card_last4,
+        card_network=card_network,
+    )
+    session.add(record)
+    await session.flush()
+    await session.refresh(record)
+    return record

db/models.py

@@ -72,6 +72,7 @@ class Subscription(Base):
     last_notification_sent = Column(DateTime(timezone=True), nullable=True)
     provider = Column(String, nullable=True)
     skip_notifications = Column(Boolean, default=False)
+    auto_renew_enabled = Column(Boolean, default=False, index=True)
 
     user = relationship("User", back_populates="subscriptions")
 
@@ -112,6 +113,19 @@ class Payment(Base):
                                    back_populates="payments_where_used")
 
 
+class UserBilling(Base):
+    __tablename__ = "user_billing"
+
+    user_id = Column(BigInteger, ForeignKey("users.user_id"), primary_key=True)
+    # Saved payment method for off-session recurring charges (YooKassa)
+    yookassa_payment_method_id = Column(String, nullable=True, unique=True)
+    card_last4 = Column(String, nullable=True)
+    card_network = Column(String, nullable=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now(), nullable=True)
+
+    user = relationship("User")
+
 class PromoCode(Base):
     __tablename__ = "promo_codes"