feat: add recharge callback processing

apps/api/tests.py

@@ -1,6 +1,8 @@
 import uuid
 import base64
+import json
 import tempfile
+from decimal import Decimal
 from pathlib import Path
 from unittest.mock import patch
 
@@ -20,7 +22,11 @@ from apps.ai.providers import (
     ImageGenerationResult,
     TextGenerationResult,
 )
-from apps.billing.models import CallRecord, PointsLedger, PricingRule
+from apps.billing.models import CallRecord, PointsLedger, PricingRule, RechargeOrder
+from apps.billing.payment_gateways import (
+    build_mock_alipay_signature,
+    build_mock_body_signature,
+)
 from apps.users.models import ApiKey
 from apps.users.models import UserWallet
 
@@ -191,6 +197,184 @@ class BalanceApiTests(TestCase):
         self.assertEqual(response.data["error"]["code"], "unauthorized")
 
 
+@override_settings(
+    PAYMENT_CALLBACK_MODE="mock",
+    PAYMENT_MOCK_CALLBACK_SECRET="test-payment-callback-secret",
+)
+class RechargeCallbackApiTests(TestCase):
+    wechat_url = "/api/v1/recharge/callback/wechat"
+    alipay_url = "/api/v1/recharge/callback/alipay"
+
+    def setUp(self):
+        suffix = uuid.uuid4().hex[:8]
+        self.user = get_user_model().objects.create_user(
+            username=f"recharge-user-{suffix}",
+            email=f"recharge-user-{suffix}@example.com",
+            password="password",
+        )
+        self.wallet = UserWallet.objects.create(user=self.user, points_balance=100)
+        self.client = APIClient(enforce_csrf_checks=True)
+
+    def create_order(
+        self,
+        *,
+        amount="20.00",
+        points_granted=200,
+        pay_method=RechargeOrder.PayMethod.WEIXIN,
+    ) -> RechargeOrder:
+        return RechargeOrder.objects.create(
+            user=self.user,
+            order_no=f"R{uuid.uuid4().hex[:12]}",
+            amount_money=Decimal(amount),
+            pay_method=pay_method,
+            exchange_rate=Decimal("10.0000"),
+            points_granted=points_granted,
+        )
+
+    def signed_wechat_body(self, order, *, total_cents=2000):
+        payload = {
+            "event_type": "TRANSACTION.SUCCESS",
+            "resource": {
+                "trade_state": "SUCCESS",
+                "out_trade_no": order.order_no,
+                "transaction_id": "wx-txn-001",
+                "success_time": "2026-07-03T00:00:00+08:00",
+                "amount": {"total": total_cents},
+            },
+        }
+        body = json.dumps(payload, separators=(",", ":")).encode("utf-8")
+        return body, build_mock_body_signature(body)
+
+    def signed_alipay_payload(self, order, *, total_amount="20.00"):
+        payload = {
+            "trade_status": "TRADE_SUCCESS",
+            "out_trade_no": order.order_no,
+            "trade_no": "ali-txn-001",
+            "total_amount": total_amount,
+            "gmt_payment": "2026-07-03 00:00:00",
+        }
+        payload["sign"] = build_mock_alipay_signature(payload)
+        return payload
+
+    def test_wechat_callback_credits_once_and_is_csrf_exempt(self):
+        order = self.create_order(amount="20.00", points_granted=200)
+        body, signature = self.signed_wechat_body(order)
+
+        first = self.client.post(
+            self.wechat_url,
+            data=body,
+            content_type="application/json",
+            HTTP_WECHATPAY_SIGNATURE=signature,
+        )
+        second = self.client.post(
+            self.wechat_url,
+            data=body,
+            content_type="application/json",
+            HTTP_WECHATPAY_SIGNATURE=signature,
+        )
+
+        self.assertEqual(first.status_code, 200)
+        self.assertEqual(second.status_code, 200)
+        self.assertEqual(first.data["code"], "SUCCESS")
+        self.wallet.refresh_from_db()
+        order.refresh_from_db()
+        self.assertEqual(self.wallet.points_balance, 300)
+        self.assertEqual(order.status, RechargeOrder.Status.PAID)
+        self.assertEqual(order.payment_txn_no, "wx-txn-001")
+        self.assertEqual(
+            PointsLedger.objects.filter(
+                user=self.user,
+                ref_order_id=order.id,
+                change_type=PointsLedger.ChangeType.RECHARGE,
+            ).count(),
+            1,
+        )
+
+    def test_wechat_callback_rejects_bad_signature_without_crediting(self):
+        order = self.create_order(amount="20.00", points_granted=200)
+        body, _signature = self.signed_wechat_body(order)
+
+        response = self.client.post(
+            self.wechat_url,
+            data=body,
+            content_type="application/json",
+            HTTP_WECHATPAY_SIGNATURE="bad-signature",
+        )
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(response.data["error"]["code"], "signature_invalid")
+        self.wallet.refresh_from_db()
+        order.refresh_from_db()
+        self.assertEqual(self.wallet.points_balance, 100)
+        self.assertEqual(order.status, RechargeOrder.Status.PENDING)
+        self.assertFalse(PointsLedger.objects.filter(ref_order_id=order.id).exists())
+
+    def test_wechat_callback_rejects_amount_mismatch_without_crediting(self):
+        order = self.create_order(amount="20.00", points_granted=200)
+        body, signature = self.signed_wechat_body(order, total_cents=1999)
+
+        response = self.client.post(
+            self.wechat_url,
+            data=body,
+            content_type="application/json",
+            HTTP_WECHATPAY_SIGNATURE=signature,
+        )
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(response.data["error"]["code"], "amount_mismatch")
+        self.wallet.refresh_from_db()
+        order.refresh_from_db()
+        self.assertEqual(self.wallet.points_balance, 100)
+        self.assertEqual(order.status, RechargeOrder.Status.PENDING)
+        self.assertFalse(PointsLedger.objects.filter(ref_order_id=order.id).exists())
+
+    def test_alipay_callback_credits_once_returns_success_and_is_csrf_exempt(self):
+        order = self.create_order(
+            amount="20.00",
+            points_granted=200,
+            pay_method=RechargeOrder.PayMethod.ALIPAY,
+        )
+        payload = self.signed_alipay_payload(order)
+
+        first = self.client.post(self.alipay_url, data=payload)
+        second = self.client.post(self.alipay_url, data=payload)
+
+        self.assertEqual(first.status_code, 200)
+        self.assertEqual(second.status_code, 200)
+        self.assertEqual(first.content, b"success")
+        self.wallet.refresh_from_db()
+        order.refresh_from_db()
+        self.assertEqual(self.wallet.points_balance, 300)
+        self.assertEqual(order.status, RechargeOrder.Status.PAID)
+        self.assertEqual(order.payment_txn_no, "ali-txn-001")
+        self.assertEqual(
+            PointsLedger.objects.filter(
+                ref_order_id=order.id,
+                change_type=PointsLedger.ChangeType.RECHARGE,
+            ).count(),
+            1,
+        )
+
+    def test_alipay_callback_rejects_bad_signature_without_crediting(self):
+        order = self.create_order(
+            amount="20.00",
+            points_granted=200,
+            pay_method=RechargeOrder.PayMethod.ALIPAY,
+        )
+        payload = self.signed_alipay_payload(order)
+        payload["sign"] = "bad-signature"
+
+        response = self.client.post(self.alipay_url, data=payload)
+
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(response.content, b"fail")
+        self.wallet.refresh_from_db()
+        order.refresh_from_db()
+        self.assertEqual(self.wallet.points_balance, 100)
+        self.assertEqual(order.status, RechargeOrder.Status.PENDING)
+        self.assertFalse(PointsLedger.objects.filter(ref_order_id=order.id).exists())
+
+
 class FakeGenerationProvider:
     def __init__(self, *, capabilities=None):
         self._capabilities = set(capabilities or {"text", "image", "vision"})