From 29a76e342e5fe34ab73d4b9958c3526b578df990 Mon Sep 17 00:00:00 2001
From: Bohdan Horbeshko <bodqhrohro@gmail.com>
Date: Fri, 23 May 2025 13:56:12 -0400
Subject: [PATCH] Handle MUC exits

---
 telegram/utils.go | 19 ++++++++++++++++++
 xmpp/handlers.go  | 51 ++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 61 insertions(+), 9 deletions(-)

diff --git a/telegram/utils.go b/telegram/utils.go
index ae66953..d10810d 100644
--- a/telegram/utils.go
+++ b/telegram/utils.go
@@ -539,6 +539,8 @@ func (c *Client) JoinMUC(chatId int64, resource string, limit *MessageLimit) {
 	}
 	c.locks.mucCacheLock.Unlock()
 
+	log.Debugf("Resources in MUC %v: %v", chatId, mucState.Resources)
+
 	c.sendMUCStatuses(chatId)
 
 	messages, err := c.getNLastMessages(chatId, limit)
@@ -549,6 +551,23 @@ func (c *Client) JoinMUC(chatId int64, resource string, limit *MessageLimit) {
 	c.sendMUCSubject(chatId, resource)
 }
 
+// LeaveMUC removes MUC date from the cache
+func (c *Client) LeaveMUC(chatId int64, resource string) {
+	c.locks.mucCacheLock.Lock()
+	defer c.locks.mucCacheLock.Unlock()
+
+	mucState, ok := c.mucCache[chatId]
+	if !ok || mucState == nil {
+		return
+	}
+	delete(mucState.Resources, resource)
+	log.Debugf("Resources in MUC %v: %v", chatId, mucState.Resources)
+
+	if len(mucState.Resources) == 0 {
+		delete(c.mucCache, chatId)
+	}
+}
+
 func (c *Client) getFullName(user *client.User) string {
 	fullName := user.FirstName
 	if user.LastName != "" {
diff --git a/xmpp/handlers.go b/xmpp/handlers.go
index 1991d78..a914214 100644
--- a/xmpp/handlers.go
+++ b/xmpp/handlers.go
@@ -379,7 +379,7 @@ func HandlePresence(s xmpp.Sender, p stanza.Packet) {
 		handleMUCPresence(s, prs, mucExt)
 		return
 	}
-	tryHandleMUCNicknameChange(s, prs)
+	tryHandleMUCPresence(s, prs)
 }
 
 func handleSubscription(s xmpp.Sender, p stanza.Presence) {
@@ -567,11 +567,7 @@ func handleMUCPresence(s xmpp.Sender, p stanza.Presence, mucExt stanza.MucPresen
 	}
 }
 
-func tryHandleMUCNicknameChange(s xmpp.Sender, p stanza.Presence) {
-	if p.Type != "" {
-		return
-	}
-
+func tryHandleMUCPresence(s xmpp.Sender, p stanza.Presence) {
 	toBare, nickname, ok := gateway.SplitJID(p.To)
 	if !ok || nickname == "" {
 		return
@@ -608,16 +604,25 @@ func tryHandleMUCNicknameChange(s xmpp.Sender, p stanza.Presence) {
 		return
 	}
 
-	log.Warn("🗿 Yes")
-
 	component, ok := s.(*xmpp.Component)
 	if !ok {
 		log.Error("Not a component")
 		return
 	}
 
+	switch p.Type {
+	case "":
+		handleMUCNicknameChange(component, p, session, chatId, toBare)
+	case stanza.PresenceTypeUnavailable:
+		handleMUCUnavailable(component, p, session, chatId, fromResource)
+	}
+}
+
+func handleMUCNicknameChange(component *xmpp.Component, p stanza.Presence, session *telegram.Client, chatId int64, toBare string) {
+	log.Warn("🗿 Yes")
+
 	from := toBare
-	nickname, ok = session.GetMyMUCNickname(chatId)
+	nickname, ok := session.GetMyMUCNickname(chatId)
 	if ok {
 		from = from+"/"+nickname
 	}
@@ -638,6 +643,34 @@ func tryHandleMUCNicknameChange(s xmpp.Sender, p stanza.Presence) {
 	gateway.ResumableSend(component, reply)
 }
 
+func handleMUCUnavailable(component *xmpp.Component, p stanza.Presence, session *telegram.Client, chatId int64, resource string) {
+	log.Warn("No, it's a MUC exit")
+
+	session.LeaveMUC(chatId, resource)
+
+	reply := &stanza.Presence{
+		Attrs: stanza.Attrs{
+			From:  p.To,
+			To:    p.From,
+			Id:    p.Id,
+			Type:  stanza.PresenceTypeUnavailable,
+		},
+		Extensions: []stanza.PresExtension{
+			extensions.PresenceXMucUserExtension{
+				Item: extensions.PresenceXMucUserItem{
+					Affiliation: "member",
+					Jid:         p.From,
+					Role:        "none",
+				},
+				Statuses: []extensions.PresenceXMucUserStatus{
+					extensions.PresenceXMucUserStatus{Code: 110},
+				},
+			},
+		},
+	}
+	gateway.ResumableSend(component, reply)
+}
+
 func handleGetVcardIq(s xmpp.Sender, iq *stanza.IQ, typ byte) {
 	log.WithFields(log.Fields{
 		"from": iq.From,