From 417917623637fb5eb17416a268f0279922a028bc Mon Sep 17 00:00:00 2001
From: Jesse de Wit <witdejesse@hotmail.com>
Date: Fri, 8 Sep 2023 14:35:07 +0200
Subject: [PATCH] lsps2: temporary_channel_failure on low funds

---
 cln/cln_client.go          | 5 +++++
 lsps2/intercept_handler.go | 9 ++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/cln/cln_client.go b/cln/cln_client.go
index 29098064..5c5f53e6 100644
--- a/cln/cln_client.go
+++ b/cln/cln_client.go
@@ -12,6 +12,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/elementsproject/glightning/glightning"
+	"github.com/elementsproject/glightning/jrpc2"
 	"golang.org/x/exp/slices"
 )
 
@@ -126,6 +127,10 @@ func (c *ClnClient) OpenChannel(req *lightning.OpenChannelRequest) (*wire.OutPoi
 
 	if err != nil {
 		log.Printf("CLN: client.FundChannelExt(%v, %v) error: %v", pubkey, req.CapacitySat, err)
+		rpcError, ok := err.(*jrpc2.RpcError)
+		if ok && rpcError.Code == 301 {
+			return nil, fmt.Errorf("not enough funds: %w", err)
+		}
 		return nil, err
 	}
 
diff --git a/lsps2/intercept_handler.go b/lsps2/intercept_handler.go
index 5a3ec6ed..91b9a811 100644
--- a/lsps2/intercept_handler.go
+++ b/lsps2/intercept_handler.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log"
 	"math"
+	"strings"
 	"time"
 
 	"github.com/breez/lspd/chain"
@@ -500,6 +501,12 @@ func (i *Interceptor) ensureChannelOpen(payment *paymentState) {
 				capacity,
 				err,
 			)
+
+			code := shared.FAILURE_UNKNOWN_NEXT_PEER
+			if strings.Contains(err.Error(), "not enough funds") {
+				code = shared.FAILURE_TEMPORARY_CHANNEL_FAILURE
+			}
+
 			// TODO: Verify that a client disconnect before receiving
 			// funding_signed doesn't cause the OpenChannel call to error.
 			// unknown_next_peer should only be returned if the client rejects
@@ -508,7 +515,7 @@ func (i *Interceptor) ensureChannelOpen(payment *paymentState) {
 			// temporary_channel_failure should be returned.
 			i.paymentFailure <- &paymentFailureEvent{
 				paymentId: payment.id,
-				code:      shared.FAILURE_UNKNOWN_NEXT_PEER,
+				code:      code,
 			}
 			return
 		}