From 4e7adbc290ad0a0ac3d40cfdff39bae7df7c7b8b Mon Sep 17 00:00:00 2001
From: Ximon Eighteen <3304436+ximon18@users.noreply.github.com>
Date: Thu, 27 Feb 2025 10:52:12 +0100
Subject: [PATCH] Return more information about the fake server response entry
 matched by Stelline.

---
 src/stelline/connection.rs |  5 ++---
 src/stelline/dgram.rs      |  5 ++---
 src/stelline/server.rs     | 19 +++++++++++++++----
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/stelline/connection.rs b/src/stelline/connection.rs
index 9c057bc1..3724b44e 100644
--- a/src/stelline/connection.rs
+++ b/src/stelline/connection.rs
@@ -104,10 +104,9 @@ impl AsyncWrite for Connection {
             (),
         );
 
-        let opt_reply = do_server(&req, &self.stelline, &self.step_value);
-        if opt_reply.is_some() {
+        if let Some((opt_reply, _indices)) = do_server(&req, &self.stelline, &self.step_value) {
             // Do we need to support more than one reply?
-            self.reply = opt_reply;
+            self.reply = Some(opt_reply);
             let opt_waker = self.waker.take();
             if let Some(waker) = opt_waker {
                 waker.wake();
diff --git a/src/stelline/dgram.rs b/src/stelline/dgram.rs
index 4594568a..c4966c43 100644
--- a/src/stelline/dgram.rs
+++ b/src/stelline/dgram.rs
@@ -114,12 +114,11 @@ impl AsyncDgramSend for DgramConnection {
             mock_transport_ctx.clone(),
             (),
         );
-        let opt_reply = do_server(&req, &self.stelline, &self.step_value);
         let len = buf.len();
-        if opt_reply.is_some() {
+        if let Some((opt_reply, _indices)) = do_server(&req, &self.stelline, &self.step_value) {
             // Do we need to support more than one reply?
             let mut reply = self.reply.lock().unwrap();
-            *reply = opt_reply;
+            *reply = Some(opt_reply);
             drop(reply);
             let mut waker = self.waker.lock().unwrap();
             let opt_waker = (*waker).take();
diff --git a/src/stelline/server.rs b/src/stelline/server.rs
index 0f8a316c..84c1f097 100644
--- a/src/stelline/server.rs
+++ b/src/stelline/server.rs
@@ -16,11 +16,20 @@ use super::matches::match_msg;
 use super::parse_stelline;
 use super::parse_stelline::{Adjust, Reply, Stelline};
 
+/// Gets a matching Stelline range entry.
+/// 
+/// Entries inside a RANGE_BEGIN/RANGE_END block within a Stelline file define
+/// queries to match and if matched the response to serve to that query.
+/// 
+/// The _last_ matching entry is returned, as apparently that "works better if
+/// the (Stelline) RPL is written with a recursive resolver in mind", along
+/// with the zero based index of the range the entry was found in, and the
+/// zero based index of the entry within that range.
 pub fn do_server<'a, Oct, Target>(
     req: &'a Request<Oct>,
     stelline: &Stelline,
     step_value: &CurrStepValue,
-) -> Option<AdditionalBuilder<Target>>
+) -> Option<(AdditionalBuilder<Target>, (usize, usize))>
 where
     <Oct as Octets>::Range<'a>: Clone,
     Oct: Clone + Octets + 'a + Send + Sync,
@@ -30,6 +39,7 @@ where
     let ranges = &stelline.scenario.ranges;
     let step = step_value.get();
     let mut opt_entry = None;
+    let mut last_found_indices: Option<(usize, usize)> = None;
     let msg = req.message();
 
     // Take the last entry. That works better if the RPL is written with
@@ -39,7 +49,7 @@ where
         msg.header().opcode(),
         msg.first_question().unwrap().qtype()
     );
-    for range in ranges {
+    for (range_idx, range) in ranges.iter().enumerate() {
         trace!(
             "Checking against range {} <= {}",
             range.start_value,
@@ -48,10 +58,11 @@ where
         if step < range.start_value || step > range.end_value {
             continue;
         }
-        for entry in &range.entry {
+        for (entry_idx, entry) in range.entry.iter().enumerate() {
             if match_msg(entry, req, true) {
                 trace!("Match found");
                 opt_entry = Some(entry);
+                last_found_indices = Some((range_idx, entry_idx))
             }
         }
     }
@@ -59,7 +70,7 @@ where
     match opt_entry {
         Some(entry) => {
             let reply = do_adjust(entry, msg);
-            Some(reply)
+            Some((reply, last_found_indices.unwrap()))
         }
         None => {
             trace!("No matching reply found");