From aedf66c73dea867f4ee84241daede72cc85f53f9 Mon Sep 17 00:00:00 2001
From: delthas <delthas@dille.cc>
Date: Fri, 20 Mar 2020 03:05:14 +0100
Subject: [PATCH] Fix MODE downstream support

- Fix replies without client as first argument
- Replace wrong prefix check with a proper entity type check
---
 downstream.go | 34 +++++++++++++---------------------
 upstream.go   | 21 +++++++++++++++------
 2 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/downstream.go b/downstream.go
index b39464b..f8af419 100644
--- a/downstream.go
+++ b/downstream.go
@@ -150,16 +150,11 @@ func (dc *downstreamConn) upstream() *upstreamConn {
 	return upstream
 }
 
-func (dc *downstreamConn) marshalEntity(uc *upstreamConn, name string) string {
-	for _, r := range name {
-		switch r {
-		// TODO: support upstream ISUPPORT channel prefixes
-		case '#', '&', '+', '!':
-			return dc.marshalChannel(uc, name)
-		}
-		break
+func (dc *downstreamConn) marshalEntity(uc *upstreamConn, entity string) string {
+	if uc.isChannel(entity) {
+		return dc.marshalChannel(uc, entity)
 	}
-	return dc.marshalNick(uc, name)
+	return dc.marshalNick(uc, entity)
 }
 
 func (dc *downstreamConn) marshalChannel(uc *upstreamConn, name string) string {
@@ -852,10 +847,6 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			}
 		}
 	case "MODE":
-		if msg.Prefix == nil {
-			return fmt.Errorf("missing prefix")
-		}
-
 		var name string
 		if err := parseMessageParams(msg, &name); err != nil {
 			return err
@@ -866,12 +857,13 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 			modeStr = msg.Params[1]
 		}
 
-		if msg.Prefix.Name != name {
-			uc, upstreamName, err := dc.unmarshalEntity(name)
-			if err != nil {
-				return err
-			}
+		uc, upstreamName, err := dc.unmarshalEntity(name)
+		if err != nil {
+			return err
+		}
 
+		if uc.isChannel(upstreamName) {
+			// TODO: handle MODE channel mode arguments
 			if modeStr != "" {
 				uc.SendMessage(&irc.Message{
 					Command: "MODE",
@@ -882,14 +874,14 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				if !ok {
 					return ircError{&irc.Message{
 						Command: irc.ERR_NOSUCHCHANNEL,
-						Params:  []string{name, "No such channel"},
+						Params:  []string{dc.nick, name, "No such channel"},
 					}}
 				}
 
 				dc.SendMessage(&irc.Message{
 					Prefix:  dc.srv.prefix(),
 					Command: irc.RPL_CHANNELMODEIS,
-					Params:  []string{name, string(ch.modes)},
+					Params:  []string{dc.nick, name, string(ch.modes)},
 				})
 			}
 		} else {
@@ -911,7 +903,7 @@ func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
 				dc.SendMessage(&irc.Message{
 					Prefix:  dc.srv.prefix(),
 					Command: irc.RPL_UMODEIS,
-					Params:  []string{""}, // TODO
+					Params:  []string{dc.nick, ""}, // TODO
 				})
 			}
 		}
diff --git a/upstream.go b/upstream.go
index bef66e2..f6be1f4 100644
--- a/upstream.go
+++ b/upstream.go
@@ -134,6 +134,18 @@ func (uc *upstreamConn) getChannel(name string) (*upstreamChannel, error) {
 	return ch, nil
 }
 
+func (uc *upstreamConn) isChannel(entity string) bool {
+	for _, r := range entity {
+		switch r {
+		// TODO: support upstream ISUPPORT channel prefixes
+		case '#', '&', '+', '!':
+			return true
+		}
+		break
+	}
+	return false
+}
+
 func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 	switch msg.Command {
 	case "PING":
@@ -143,21 +155,18 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		})
 		return nil
 	case "MODE":
-		if msg.Prefix == nil {
-			return fmt.Errorf("missing prefix")
-		}
-
 		var name, modeStr string
 		if err := parseMessageParams(msg, &name, &modeStr); err != nil {
 			return err
 		}
 
-		if name == msg.Prefix.Name { // user mode change
+		if !uc.isChannel(name) { // user mode change
 			if name != uc.nick {
-				return fmt.Errorf("received MODE message for unknow nick %q", name)
+				return fmt.Errorf("received MODE message for unknown nick %q", name)
 			}
 			return uc.modes.Apply(modeStr)
 		} else { // channel mode change
+			// TODO: handle MODE channel mode arguments
 			ch, err := uc.getChannel(name)
 			if err != nil {
 				return err