From 64d07558d97a59bf84e9e980bade2360d029f5ba Mon Sep 17 00:00:00 2001
From: Conner Fromknecht <conner@lightning.engineering>
Date: Thu, 6 May 2021 09:18:42 -0700
Subject: [PATCH] lnrpc: set either payHash or setId depending on payreq type

---
 lnrpc/routerrpc/router_backend.go | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/lnrpc/routerrpc/router_backend.go b/lnrpc/routerrpc/router_backend.go
index f6a70eba..49d60ad0 100644
--- a/lnrpc/routerrpc/router_backend.go
+++ b/lnrpc/routerrpc/router_backend.go
@@ -702,9 +702,31 @@ func (r *RouterBackend) extractIntentFromSendRequest(
 			payIntent.MaxParts = 1
 		}
 
-		err = payIntent.SetPaymentHash(*payReq.PaymentHash)
-		if err != nil {
-			return nil, err
+		if payReq.Features.HasFeature(lnwire.AMPOptional) {
+			// Generate random SetID and root share.
+			var setID [32]byte
+			_, err = rand.Read(setID[:])
+			if err != nil {
+				return nil, err
+			}
+
+			var rootShare [32]byte
+			_, err = rand.Read(rootShare[:])
+			if err != nil {
+				return nil, err
+			}
+			err := payIntent.SetAMP(&routing.AMPOptions{
+				SetID:     setID,
+				RootShare: rootShare,
+			})
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			err = payIntent.SetPaymentHash(*payReq.PaymentHash)
+			if err != nil {
+				return nil, err
+			}
 		}
 
 		destKey := payReq.Destination.SerializeCompressed()