From 8e75ebf5dcda31fcea9a9db58253893a0a124b03 Mon Sep 17 00:00:00 2001
From: Marshal <marshal@example.com>
Date: Thu, 6 Aug 2026 18:18:02 +0000
Subject: [PATCH] fix(cbe): update response for settled transactions to
 indicate Already paid

---
 .../src/modules/cbe-bill/cbe-bill.service.ts  | 24 +++++--------------
 integration/src/cbe-bill.it.ts                | 14 +++++------
 2 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/apps/edr-payment-api/src/modules/cbe-bill/cbe-bill.service.ts b/apps/edr-payment-api/src/modules/cbe-bill/cbe-bill.service.ts
index 8a915ece7..1c6926b8a 100644
--- a/apps/edr-payment-api/src/modules/cbe-bill/cbe-bill.service.ts
+++ b/apps/edr-payment-api/src/modules/cbe-bill/cbe-bill.service.ts
@@ -184,24 +184,12 @@ export class CbeBillService {
     );
     if (prior) {
       if (prior.tradeStatus === "SUCCESS") {
-        // A replay must be the SAME attempt. A reused id with different money details is
-        // not a retry — echoing the stored success would fake a settlement that never ran.
-        const orig = prior.requestPayload as unknown as
-          | CbePaymentRequestDto
-          | undefined;
-        if (
-          orig &&
-          (orig.Bill_Id !== dto.Bill_Id ||
-            orig.Cbe_Txn_Ref !== dto.Cbe_Txn_Ref ||
-            Number(orig.Amount) !== Number(dto.Amount))
-        ) {
-          return mapPaymentFailure(
-            dto,
-            "Duplicate End_To_End_Txn_Id",
-          );
-        }
-        // Replay the stored body verbatim. Never re-settle.
-        return prior.responsePayload as unknown as CbePaymentResponseDto;
+        // Per CBE integration request: a settled End_To_End_Txn_Id never replays the stored
+        // success — every repeat answers "Already paid". Money moved exactly once (the first
+        // call); this only changes what a duplicate hears back. NOTE this diverges from the
+        // original §6.5 replay design: if CBE retries because our SUCCESS response was lost
+        // in transit, it now sees FAILED for a debit we kept — reconcile such cases manually.
+        return mapPaymentFailure(dto, "Already paid");
       }
       if (prior.tradeStatus === "PENDING") {
         return mapPaymentFailure(dto, "Payment in progress");
diff --git a/integration/src/cbe-bill.it.ts b/integration/src/cbe-bill.it.ts
index f630e9a88..0d1fc7e0e 100644
--- a/integration/src/cbe-bill.it.ts
+++ b/integration/src/cbe-bill.it.ts
@@ -129,7 +129,6 @@ describe("CBE Unified Bill (payment service as biller)", () => {
   });
 
   let settleBody: Record<string, string>;
-  let settledTxnRef: string;
 
   it("settles the freight invoice when CBE reports the debit", async () => {
     const invoice = await currentInvoice(invoiceId);
@@ -147,7 +146,6 @@ describe("CBE Unified Bill (payment service as biller)", () => {
     const res = await cbe(token, "/cbe/payment", settleBody);
     expect(res.status).toBe(200);
     expect(res.body.Response_Code).toBe("0");
-    settledTxnRef = res.body.Destination_Txn_Ref;
 
     const paid = await poll<{ status: string }>(
       "invoice PAID via CBE bill",
@@ -159,22 +157,22 @@ describe("CBE Unified Bill (payment service as biller)", () => {
     expect(paid.status).toBe("PAID");
   });
 
-  it("replays the stored success when CBE retries the same attempt verbatim", async () => {
+  it("answers 'Already paid' when the settled attempt is sent again verbatim", async () => {
     const res = await cbe(token, "/cbe/payment", settleBody);
     expect(res.status).toBe(200);
-    expect(res.body.Response_Code).toBe("0");
-    // The stored body, not a re-settlement — same order id as the first answer.
-    expect(res.body.Destination_Txn_Ref).toBe(settledTxnRef);
+    expect(res.body.Status).toBe("FAILED");
+    expect(res.body.Response_Code).toBe("2");
+    expect(res.body.Response_Description).toBe("Already paid");
   });
 
-  it("rejects a settled End_To_End_Txn_Id reused with a different amount", async () => {
+  it("answers 'Already paid' when the settled End_To_End_Txn_Id is reused with a different amount", async () => {
     const res = await cbe(token, "/cbe/payment", {
       ...settleBody,
       Amount: "1.00",
     });
     expect(res.status).toBe(200);
     expect(res.body.Response_Code).toBe("2");
-    expect(res.body.Response_Description).toBe("Duplicate End_To_End_Txn_Id");
+    expect(res.body.Response_Description).toBe("Already paid");
   });
 
   it("rejects a second debit on the same bill", async () => {