From 0e9ef1f97cabf0b9cdb8cbc59de5c443456891c3 Mon Sep 17 00:00:00 2001
From: Gregory Anders <greg@gpanders.com>
Date: Wed, 9 Jun 2021 13:58:27 -0600
Subject: [PATCH] Forward user mode changes in single-upstream mode

References: https://todo.sr.ht/~emersion/soju/20
---
 downstream.go | 15 +++++++++++++--
 upstream.go   | 39 ++++++++++++++++++++++++++++-----------
 2 files changed, 41 insertions(+), 13 deletions(-)

diff --git a/downstream.go b/downstream.go
index 8e94095..09dc4f5 100644
--- a/downstream.go
+++ b/downstream.go
@@ -1102,6 +1102,13 @@ func (dc *downstreamConn) welcome() error {
 	for _, msg := range generateIsupport(dc.srv.prefix(), dc.nick, isupport) {
 		dc.SendMessage(msg)
 	}
+	if uc := dc.upstream(); uc != nil {
+		dc.SendMessage(&irc.Message{
+			Prefix:  dc.srv.prefix(),
+			Command: irc.RPL_UMODEIS,
+			Params:  []string{dc.nick, string(uc.modes)},
+		})
+	}
 	dc.SendMessage(&irc.Message{
 		Prefix:  dc.srv.prefix(),
 		Command: irc.ERR_NOMOTD,
@@ -1601,11 +1608,15 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 					})
 				})
 			} else {
-				// TODO: only do this in multi-upstream mode
+				var userMode string
+				if uc := dc.upstream(); uc != nil {
+					userMode = string(uc.modes)
+				}
+
 				dc.SendMessage(&irc.Message{
 					Prefix:  dc.srv.prefix(),
 					Command: irc.RPL_UMODEIS,
-					Params:  []string{dc.nick, ""}, // TODO
+					Params:  []string{dc.nick, userMode},
 				})
 			}
 			return nil
diff --git a/upstream.go b/upstream.go
index 1f42a24..fb64b20 100644
--- a/upstream.go
+++ b/upstream.go
@@ -672,11 +672,11 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return nil
 		}
 
-		uc.forEachDownstreamByID(downstreamID, func (dc *downstreamConn) {
-			dc.SendMessage(&irc.Message {
-				Prefix: uc.srv.prefix(),
+		uc.forEachDownstreamByID(downstreamID, func(dc *downstreamConn) {
+			dc.SendMessage(&irc.Message{
+				Prefix:  uc.srv.prefix(),
 				Command: msg.Command,
-				Params: msg.Params,
+				Params:  msg.Params,
 			})
 		})
 	case "BATCH":
@@ -932,8 +932,18 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			if name != uc.nick {
 				return fmt.Errorf("received MODE message for unknown nick %q", name)
 			}
-			return uc.modes.Apply(modeStr)
-			// TODO: notify downstreams about user mode change?
+
+			if err := uc.modes.Apply(modeStr); err != nil {
+				return err
+			}
+
+			uc.forEachDownstream(func(dc *downstreamConn) {
+				if dc.upstream() == nil {
+					return
+				}
+
+				dc.SendMessage(msg)
+			})
 		} else { // channel mode change
 			ch, err := uc.getChannel(name)
 			if err != nil {
@@ -982,7 +992,14 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		if err := uc.modes.Apply(modeStr); err != nil {
 			return err
 		}
-		// TODO: send RPL_UMODEIS to downstream connections when applicable
+
+		uc.forEachDownstream(func(dc *downstreamConn) {
+			if dc.upstream() == nil {
+				return
+			}
+
+			dc.SendMessage(msg)
+		})
 	case irc.RPL_CHANNELMODEIS:
 		var channel string
 		if err := parseMessageParams(msg, nil, &channel); err != nil {
@@ -1442,11 +1459,11 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 			return nil
 		}
 
-		uc.forEachDownstreamByID(downstreamID, func (dc *downstreamConn) {
-			dc.SendMessage(&irc.Message {
-				Prefix: uc.srv.prefix(),
+		uc.forEachDownstreamByID(downstreamID, func(dc *downstreamConn) {
+			dc.SendMessage(&irc.Message{
+				Prefix:  uc.srv.prefix(),
 				Command: msg.Command,
-				Params: msg.Params,
+				Params:  msg.Params,
 			})
 		})
 	case irc.RPL_LISTSTART: