fix(promo): Исправлена ошибка с удалением промокода на скидку

Исправлен баг, когда промокод на скидку не мог быть удалён, если пользователь применил скидку, но не воспользовался ей.
Добавлено истечение времени действия промокода, даже если промокод на скидку уже был введён

db/dal/active_discount_dal.py

@@ -69,3 +69,20 @@ async def clear_active_discount(
     if cleared:
         logging.info(f"Active discount cleared for user {user_id}")
     return cleared
+
+
+async def clear_active_discounts_by_promo_code(
+    session: AsyncSession,
+    promo_code_id: int
+) -> int:
+    """
+    Clear all active discounts associated with a specific promo code.
+    Returns the number of discounts cleared.
+    """
+    stmt = delete(ActiveDiscount).where(ActiveDiscount.promo_code_id == promo_code_id)
+    result = await session.execute(stmt)
+    await session.flush()
+    count = result.rowcount
+    if count > 0:
+        logging.info(f"Cleared {count} active discount(s) for promo_code_id={promo_code_id}")
+    return count

db/dal/promo_code_dal.py

@@ -132,16 +132,29 @@ async def update_promo_code(session: AsyncSession, promo_id: int,
 
 
 async def delete_promo_code(session: AsyncSession, promo_id: int) -> Optional[PromoCode]:
+    from db.dal import active_discount_dal
+
     promo = await get_promo_code_by_id(session, promo_id)
     if not promo:
         return None
-    # First, delete related activations due to foreign key constraint
+
+    # 1. Clear all active discounts referencing this promo code
+    await active_discount_dal.clear_active_discounts_by_promo_code(session, promo_id)
+
+    # 2. Set promo_code_id to NULL in payments table to avoid FK violation
+    stmt = update(Payment).where(Payment.promo_code_id == promo_id).values(promo_code_id=None)
+    await session.execute(stmt)
+
+    # 3. Delete related activations
     activations = await get_promo_activations_by_code_id(session, promo_id)
     for activation in activations:
         await session.delete(activation)
-    
+
+    # 4. Delete the promo code itself
     await session.delete(promo)
     await session.flush()
+
+    logging.info(f"Promo code '{promo.code}' (ID: {promo_id}) deleted successfully")
     return promo