From 81f578de767eaa4a673a6d2444081fcfa4d33052 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Wed, 10 Jul 2024 12:27:25 +0930
Subject: [PATCH] plugins/offers: neaten fetchinvoice integration.

We already parse some fields, so hand them directly rather than
having fetchinvoice behave as if it's a raw hook.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 plugins/fetchinvoice.c | 31 +++++++++----------------------
 plugins/fetchinvoice.h | 10 +++++++---
 plugins/offers.c       | 35 +++++++++++++++++++++++------------
 3 files changed, 39 insertions(+), 37 deletions(-)

diff --git a/plugins/fetchinvoice.c b/plugins/fetchinvoice.c
index 8dafab0f1..1ddcfd224 100644
--- a/plugins/fetchinvoice.c
+++ b/plugins/fetchinvoice.c
@@ -333,34 +333,21 @@ badinv:
 	return command_hook_success(cmd);
 }
 
-struct command_result *recv_modern_onion_message(struct command *cmd,
-						 const char *buf,
-						 const jsmntok_t *params)
+struct command_result *handle_invoice_onion_message(struct command *cmd,
+						    const char *buf,
+						    const jsmntok_t *om,
+						    const struct secret *pathsecret)
 {
-	const jsmntok_t *om, *secrettok;
 	struct sent *sent;
-	struct secret pathsecret;
 	struct command_result *err;
 
-	om = json_get_member(buf, params, "onion_message");
-
-	secrettok = json_get_member(buf, om, "pathsecret");
-	if (!secrettok)
+	sent = find_sent_by_secret(pathsecret);
+	if (!sent)
 		return NULL;
 
-	json_to_secret(buf, secrettok, &pathsecret);
-	sent = find_sent_by_secret(&pathsecret);
-	if (!sent) {
-		plugin_log(cmd->plugin, LOG_DBG,
-			   "No match for modern onion %.*s",
-			   json_tok_full_len(om),
-			   json_tok_full(buf, om));
-		return NULL;
-	}
-
-	plugin_log(cmd->plugin, LOG_DBG, "Received modern onion message: %.*s",
-		   json_tok_full_len(params),
-		   json_tok_full(buf, params));
+	plugin_log(cmd->plugin, LOG_DBG, "Received onion message reply for invoice_request: %.*s",
+		   json_tok_full_len(om),
+		   json_tok_full(buf, om));
 
 	err = handle_error(cmd, sent, buf, om);
 	if (err)
diff --git a/plugins/fetchinvoice.h b/plugins/fetchinvoice.h
index 1f5ef14a3..6ab7340ce 100644
--- a/plugins/fetchinvoice.h
+++ b/plugins/fetchinvoice.h
@@ -17,9 +17,13 @@ struct command_result *json_dev_rawrequest(struct command *cmd,
 					   const char *buffer,
 					   const jsmntok_t *params);
 
-struct command_result *recv_modern_onion_message(struct command *cmd,
-						 const char *buf,
-						 const jsmntok_t *params);
+/* Returns NULL if this wasn't one of ours. */
+struct command_result *handle_invoice_onion_message(struct command *cmd,
+						    const char *buf,
+						    const jsmntok_t *om,
+						    const struct secret *pathsecret);
+
+/* invoice_payment hook */
 struct command_result *invoice_payment(struct command *cmd,
 				       const char *buf,
 				       const jsmntok_t *params);
diff --git a/plugins/offers.c b/plugins/offers.c
index 84f6f01d6..dd0eaa93f 100644
--- a/plugins/offers.c
+++ b/plugins/offers.c
@@ -157,23 +157,34 @@ send_onion_reply(struct command *cmd,
 	return send_outreq(cmd->plugin, req);
 }
 
-static struct command_result *onion_message_modern_call(struct command *cmd,
-							const char *buf,
-							const jsmntok_t *params)
+static struct command_result *onion_message_recv(struct command *cmd,
+						 const char *buf,
+						 const jsmntok_t *params)
 {
-	const jsmntok_t *om, *replytok, *invreqtok, *invtok;
+	const jsmntok_t *om, *secrettok, *replytok, *invreqtok, *invtok;
 	struct blinded_path *reply_path = NULL;
-	struct command_result *res;
+ 	struct secret *secret;
 
 	if (!offers_enabled)
 		return command_hook_success(cmd);
 
-	/* FIXME: unify parsing! */
-	res = recv_modern_onion_message(cmd, buf, params);
-	if (res)
-		return res;
-
 	om = json_get_member(buf, params, "onion_message");
+	secrettok = json_get_member(buf, om, "pathsecret");
+	if (secrettok) {
+		secret = tal(tmpctx, struct secret);
+		json_to_secret(buf, secrettok, secret);
+	} else
+		secret = NULL;
+
+	/* Might be reply for fetchinvoice (which always has a secret,
+	 * so we can tell it's a response). */
+	if (secret) {
+		struct command_result *res;
+		res = handle_invoice_onion_message(cmd, buf, om, secret);
+		if (res)
+			return res;
+	}
+
 	replytok = json_get_member(buf, om, "reply_blindedpath");
 	if (replytok) {
 		reply_path = json_to_blinded_path(cmd, buf, replytok);
@@ -208,11 +219,11 @@ static struct command_result *onion_message_modern_call(struct command *cmd,
 static const struct plugin_hook hooks[] = {
 	{
 		"onion_message_recv",
-		onion_message_modern_call
+		onion_message_recv
 	},
 	{
 		"onion_message_recv_secret",
-		onion_message_modern_call
+		onion_message_recv
 	},
 	{
 		"invoice_payment",