fix

api/services/credit_pool_service.py

@@ -34,35 +34,52 @@ class CreditPoolService:
             .first()
         )
 
+    @classmethod
+    def check_credits_available(
+        cls,
+        tenant_id: str,
+        credits_required: int,
+        pool_type: str = "trial",
+    ) -> bool:
+        """check if credits are available without deducting"""
+        pool = cls.get_pool(tenant_id, pool_type)
+        if not pool:
+            return False
+        return pool.remaining_credits >= credits_required
+
     @classmethod
     def check_and_deduct_credits(
         cls,
         tenant_id: str,
         credits_required: int,
         pool_type: str = "trial",
-    ):
-        """check and deduct credits"""
+    ) -> int:
+        """check and deduct credits, returns actual credits deducted"""
 
         pool = cls.get_pool(tenant_id, pool_type)
         if not pool:
             raise QuotaExceededError("Credit pool not found")
 
-        if pool.remaining_credits < credits_required:
-            raise QuotaExceededError(
-                f"Insufficient credits. Required: {credits_required}, Available: {pool.remaining_credits}"
-            )
+        if pool.remaining_credits <= 0:
+            raise QuotaExceededError("No credits remaining")
+
+        # deduct all remaining credits if less than required
+        actual_credits = min(credits_required, pool.remaining_credits)
+
         try:
             with Session(db.engine) as session:
-                update_values = {"quota_used": pool.quota_used + credits_required}
-
-                where_conditions = [
-                    TenantCreditPool.pool_type == pool_type,
-                    TenantCreditPool.tenant_id == tenant_id,
-                    TenantCreditPool.quota_used + credits_required <= TenantCreditPool.quota_limit,
-                ]
-                stmt = update(TenantCreditPool).where(*where_conditions).values(**update_values)
+                stmt = (
+                    update(TenantCreditPool)
+                    .where(
+                        TenantCreditPool.tenant_id == tenant_id,
+                        TenantCreditPool.pool_type == pool_type,
+                    )
+                    .values(quota_used=TenantCreditPool.quota_used + actual_credits)
+                )
                 session.execute(stmt)
                 session.commit()
         except Exception:
             logger.exception("Failed to deduct credits for tenant %s", tenant_id)
             raise QuotaExceededError("Failed to deduct credits")
+
+        return actual_credits