From 1a21c05d7dd4909f7ab551a0ea7d551a2c73361f Mon Sep 17 00:00:00 2001
From: Nikita Vilunov <nikita@vilunov.me>
Date: Mon, 27 May 2024 14:24:23 +0000
Subject: [PATCH] xmpp: add support leaving MUCs via unavailable presence (#71)

Reviewed-on: https://git.vilunov.me/lavina/lavina/pulls/71
---
 crates/projection-xmpp/src/presence.rs | 110 ++++++++++++++++++-------
 1 file changed, 80 insertions(+), 30 deletions(-)

diff --git a/crates/projection-xmpp/src/presence.rs b/crates/projection-xmpp/src/presence.rs
index 5b34e5e..9e8e2e0 100644
--- a/crates/projection-xmpp/src/presence.rs
+++ b/crates/projection-xmpp/src/presence.rs
@@ -23,36 +23,17 @@ impl<'a> XmppConnection<'a> {
                 server,
                 // resources in MUCs are members' personas – not implemented (yet?)
                 resource: Some(_),
-            }) if server.0 == self.hostname_rooms => {
-                let mut muc_presence = self.retrieve_muc_presence(&name).await?;
-                muc_presence.id = p.id;
-                let subject = Message::<()> {
-                    from: Some(Jid {
-                        name: Some(name.clone()),
-                        server: Server(self.hostname_rooms.clone()),
-                        resource: None,
-                    }),
-                    id: None,
-                    to: Some(Jid {
-                        name: Some(self.user.xmpp_name.clone()),
-                        server: Server(self.hostname.clone()),
-                        resource: Some(self.user.xmpp_resource.clone()),
-                    }),
-                    r#type: MessageType::Groupchat,
-                    lang: None,
-                    subject: Some(Subject(None)),
-                    body: None,
-                    custom: vec![],
-                };
-                muc_presence.serialize(output);
-
-                let messages = self.retrieve_message_history(&name).await?;
-                for message in messages {
-                    message.serialize(output)
+            }) if server.0 == self.hostname_rooms => match p.r#type.as_deref() {
+                None => {
+                    self.join_muc(output, p.id, name).await?;
                 }
-                // The subject is the last stanza sent during a MUC join process.
-                subject.serialize(output);
-            }
+                Some("unavailable") => {
+                    self.leave_muc(output, p.id, name).await?;
+                }
+                _ => {
+                    tracing::error!("Unimplemented case")
+                }
+            },
             _ => {
                 // TODO other presence cases
                 let response = Presence::<()>::default();
@@ -62,6 +43,75 @@ impl<'a> XmppConnection<'a> {
         Ok(())
     }
 
+    async fn join_muc(&mut self, output: &mut Vec<Event<'static>>, id: Option<String>, name: Name) -> Result<()> {
+        // Response presence
+        let mut muc_presence = self.retrieve_muc_presence(&name).await?;
+        muc_presence.id = id;
+        muc_presence.serialize(output);
+
+        // N last messages from the room history before the user joined
+        let messages = self.retrieve_message_history(&name).await?;
+        for message in messages {
+            message.serialize(output)
+        }
+
+        // The subject is the last stanza sent during a MUC join process.
+        let subject = Message::<()> {
+            from: Some(Jid {
+                name: Some(name.clone()),
+                server: Server(self.hostname_rooms.clone()),
+                resource: None,
+            }),
+            id: None,
+            to: Some(Jid {
+                name: Some(self.user.xmpp_name.clone()),
+                server: Server(self.hostname.clone()),
+                resource: Some(self.user.xmpp_resource.clone()),
+            }),
+            r#type: MessageType::Groupchat,
+            lang: None,
+            subject: Some(Subject(None)),
+            body: None,
+            custom: vec![],
+        };
+        subject.serialize(output);
+        Ok(())
+    }
+
+    async fn leave_muc(&mut self, output: &mut Vec<Event<'static>>, id: Option<String>, name: Name) -> Result<()> {
+        self.user_handle.leave_room(RoomId::try_from(name.0.clone())?).await?;
+        let response = Presence {
+            id,
+            to: Some(Jid {
+                name: Some(self.user.xmpp_name.clone()),
+                server: Server(self.hostname.clone()),
+                resource: Some(self.user.xmpp_resource.clone()),
+            }),
+            from: Some(Jid {
+                name: Some(name.clone()),
+                server: Server(self.hostname_rooms.clone()),
+                resource: Some(self.user.xmpp_muc_name.clone()),
+            }),
+            r#type: Some("unavailable".into()),
+            custom: vec![XUser {
+                item: XUserItem {
+                    affiliation: Affiliation::Member,
+                    role: Role::None,
+                    jid: Jid {
+                        name: Some(self.user.xmpp_name.clone()),
+                        server: Server(self.hostname.clone()),
+                        resource: Some(self.user.xmpp_resource.clone()),
+                    },
+                },
+                self_presence: true,
+                just_created: false,
+            }],
+            ..Default::default()
+        };
+        response.serialize(output);
+        Ok(())
+    }
+
     #[tracing::instrument(skip(self, output, r#type), name = "XmppConnection::self_presence")]
     async fn self_presence(&mut self, output: &mut Vec<Event<'static>>, r#type: Option<&str>) {
         match r#type {
@@ -92,7 +142,7 @@ impl<'a> XmppConnection<'a> {
 
     #[tracing::instrument(skip(self), name = "XmppConnection::retrieve_muc_presence")]
     async fn retrieve_muc_presence(&mut self, name: &Name) -> Result<Presence<XUser>> {
-        let a = self.user_handle.join_room(RoomId::try_from(name.0.clone())?).await?;
+        let _ = self.user_handle.join_room(RoomId::try_from(name.0.clone())?).await?;
         // TODO handle bans
         let response = Presence {
             to: Some(Jid {