From 5ec9491e2268fb0617417f4885baa068404ca16a Mon Sep 17 00:00:00 2001
From: hexdev <me@killhexdev.ru>
Date: Sun, 31 May 2026 15:23:31 +0700
Subject: [PATCH] feat(pally): support customer-pays-fees scenario with
 BalanceAmount validation

---
 api/routes/pally.py         | 48 +++++++++++++++++++++++++++++--------
 tests/send_pally_webhook.py | 33 +++++++++++++++++++++----
 2 files changed, 67 insertions(+), 14 deletions(-)

diff --git a/api/routes/pally.py b/api/routes/pally.py
index 77bb993..084910c 100644
--- a/api/routes/pally.py
+++ b/api/routes/pally.py
@@ -51,8 +51,8 @@ async def pally_callback(
     
     logger.info(
         "Pally webhook received - InvId: %s, OutSum: %s, Commission: %s, TrsId: %s, Status: %s, "
-        "CurrencyIn: %s, custom: %s, SignatureValue: %s",
-        InvId, OutSum, Commission, TrsId, Status, CurrencyIn, custom, SignatureValue
+        "CurrencyIn: %s, custom: %s, BalanceAmount: %s, SignatureValue: %s",
+        InvId, OutSum, Commission, TrsId, Status, CurrencyIn, custom, BalanceAmount, SignatureValue
     )
     
     # Enhanced logging for failed payments
@@ -105,15 +105,43 @@ async def pally_callback(
         return "OK"
 
     try:
-        amount = int(float(OutSum))
-
-        # Validate payment amount
-        if bill.amount != amount:
-            logger.error(
-                "Amount mismatch for bill %s (TrsId: %s) - Expected: %s, Received: %s",
-                bill.id, TrsId, bill.amount, amount
+        # Handle fee scenarios: use BalanceAmount if available (net amount after fees),
+        # otherwise use OutSum (gross amount paid by customer)
+        if BalanceAmount is not None:
+            # Customer pays fees - BalanceAmount is the net amount credited to merchant
+            credited_amount = int(float(BalanceAmount))
+            gross_amount = int(float(OutSum))
+            
+            logger.info(
+                "Customer-pays-fees payment: bill_id=%s, expected=%s, gross_paid=%s, net_credited=%s",
+                bill.id, bill.amount, gross_amount, credited_amount
             )
-            return "OK"
+            
+            # Validate that the net credited amount matches our bill amount
+            if bill.amount != credited_amount:
+                logger.error(
+                    "Net amount mismatch for bill %s (TrsId: %s) - Expected: %s, Net credited: %s, Gross paid: %s",
+                    bill.id, TrsId, bill.amount, credited_amount, gross_amount
+                )
+                return "OK"
+                
+            amount = credited_amount  # Credit the net amount (without fees)
+            
+        else:
+            # Standard payment - OutSum should match bill amount exactly
+            amount = int(float(OutSum))
+            
+            logger.info(
+                "Standard payment: bill_id=%s, expected=%s, received=%s",
+                bill.id, bill.amount, amount
+            )
+            
+            if bill.amount != amount:
+                logger.error(
+                    "Amount mismatch for bill %s (TrsId: %s) - Expected: %s, Received: %s",
+                    bill.id, TrsId, bill.amount, amount
+                )
+                return "OK"
 
         logger.info("Processing payment: bill_id=%s, user_id=%s, amount=%s", 
                    bill.id, bill.creator_id, amount)
diff --git a/tests/send_pally_webhook.py b/tests/send_pally_webhook.py
index f5eb949..5fd6341 100644
--- a/tests/send_pally_webhook.py
+++ b/tests/send_pally_webhook.py
@@ -42,6 +42,11 @@ def main():
         choices=["SUCCESS", "FAIL", "UNDERPAID", "OVERPAID"],
         help="Статус платежа (по умолчанию SUCCESS)",
     )
+    parser.add_argument(
+        "--customer-pays-fees", 
+        action="store_true",
+        help="Симулировать сценарий 'клиент платит комиссию'"
+    )
     args = parser.parse_args()
 
     pally_token = os.environ["PALLY_TOKEN"]
@@ -52,24 +57,44 @@ def main():
     trs_id = f"LXZv3R{args.bill_id}"   # TrsId - уникальный идентификатор счета в Pally
     currency = "RUB"
     custom = None  # custom field не используется в production (остается None)
-    commission = "0.00"  # Комиссия
+    
+    # Симуляция комиссии
+    if args.customer_pays_fees:
+        # Симулируем комиссию ~10% (как в вашем продакшене: 50 -> 55.4)
+        commission_rate = 0.108  # ~10.8%
+        gross_amount = args.amount * (1 + commission_rate)
+        commission = gross_amount - args.amount
+        
+        print(f"🔄 Симулируется сценарий 'клиент платит комиссию':")
+        print(f"   Сумма заказа: {args.amount} RUB")
+        print(f"   Комиссия: {commission:.2f} RUB")
+        print(f"   Итого к оплате: {gross_amount:.2f} RUB")
+        print(f"   К зачислению: {args.amount} RUB")
+    else:
+        gross_amount = args.amount
+        commission = 0.00
 
     # Сигнатура рассчитывается с использованием InvId (который содержит bill ID)
     signature = calculate_signature(
-        str(args.amount), inv_id, pally_token
+        f"{gross_amount:.2f}", inv_id, pally_token
     )
 
     # Используем правильные имена полей согласно документации pally.info
     payload = {
         "InvId": inv_id,  # Содержит ID счета из БД
-        "OutSum": str(args.amount),
-        "Commission": commission,
+        "OutSum": f"{gross_amount:.2f}",  # Сумма, которую заплатил клиент (с комиссией)
+        "Commission": f"{commission:.2f}",
         "TrsId": trs_id,
         "Status": args.status,
         "CurrencyIn": currency,
         "custom": custom,  # None в production
         "SignatureValue": signature,
     }
+    
+    # Добавляем BalanceAmount только если клиент платит комиссию
+    if args.customer_pays_fees:
+        payload["BalanceAmount"] = str(args.amount)  # Сумма к зачислению (без комиссии)
+        payload["BalanceCurrency"] = currency
 
     print(f"{args.host}{ENDPOINT}")
     print(f"Отправляю вебхук: {payload}\n")