From 85814d9c295e995299d15a3e588f9a4ac27aceb7 Mon Sep 17 00:00:00 2001
From: Val Lorentz <progval+git@progval.net>
Date: Sat, 29 Mar 2025 21:17:09 +0100
Subject: [PATCH] Automatically attach preclients to an existing session of the
 account, if any

---
 sable_ircd/src/client.rs                      |  5 ++-
 sable_ircd/src/server/update_handler.rs       | 35 +++++++++++++++++++
 .../src/policy/standard_user_policy.rs        |  4 +++
 sable_network/src/policy/user_policy.rs       |  6 ++++
 4 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/sable_ircd/src/client.rs b/sable_ircd/src/client.rs
index ffee7450..5ad18f0d 100644
--- a/sable_ircd/src/client.rs
+++ b/sable_ircd/src/client.rs
@@ -253,14 +253,17 @@ impl PreClient {
     pub fn can_register(&self) -> bool {
         let can_register_new = self.can_register_new_user();
         let can_attach = self.can_attach_to_user().is_some();
+        let is_negotiating_caps =
+            self.progress_flags.load(Ordering::Relaxed) & ProgressFlag::CapNegotiation as u32 != 0;
 
         tracing::trace!(
             ?self,
             can_register_new,
             can_attach,
+            is_negotiating_caps,
             "PreClient::can_register"
         );
-        can_register_new || can_attach
+        (can_register_new || can_attach) && !is_negotiating_caps
     }
 
     /// Determine whether this connection is ready to register as a new user
diff --git a/sable_ircd/src/server/update_handler.rs b/sable_ircd/src/server/update_handler.rs
index a0ac7c79..37c9543d 100644
--- a/sable_ircd/src/server/update_handler.rs
+++ b/sable_ircd/src/server/update_handler.rs
@@ -4,6 +4,7 @@ use sable_network::prelude::state::{HistoricMessageSourceId, HistoricMessageTarg
 use super::*;
 use crate::errors::HandleResult;
 use crate::monitor::MonitoredItem;
+use sable_network::network::update::UserAwayChange;
 
 impl ClientServer {
     pub(super) fn handle_history_update(&self, update: NetworkHistoryUpdate) -> HandleResult {
@@ -169,6 +170,40 @@ impl ClientServer {
 
             connection.send(message::Notice::new(&self.node.name().to_string(), &user,
                     "The network is currently running in debug mode. Do not send any sensitive information such as passwords."));
+
+            if let Some(&away_reason) = user.away_reason() {
+                let fake_log_entry = NetworkHistoryUpdate {
+                    timestamp: 0,                                                       // XXX
+                    event: EventId::new(Snowflake::from_parts(self.node().id(), 0, 0)), // XXX
+                    change: NetworkStateChange::UserAwayChange(UserAwayChange {
+                        user: user.historic_id(),
+                        old_reason: None,
+                        new_reason: Some(away_reason),
+                    }),
+                    users_to_notify: vec![],
+                };
+
+                // Set away status if user has away-notify capability
+                // FIXME: suffers from https://github.com/Libera-Chat/sable/issues/155
+                self.send_now(&fake_log_entry, &connection, &fake_log_entry)?;
+            }
+
+            for membership in user.channels() {
+                let fake_join = update::ChannelJoin {
+                    membership: membership.id(),
+                    user: user.historic_id(),
+                };
+
+                let fake_log_entry = NetworkHistoryUpdate {
+                    timestamp: 0,                                                       // XXX
+                    event: EventId::new(Snowflake::from_parts(self.node().id(), 0, 0)), // XXX
+                    change: NetworkStateChange::ChannelJoin(fake_join),
+                    users_to_notify: vec![],
+                };
+
+                // Send join + topic + names
+                self.send_now(&fake_log_entry, &connection, &fake_log_entry)?;
+            }
         }
         Ok(())
     }
diff --git a/sable_network/src/policy/standard_user_policy.rs b/sable_network/src/policy/standard_user_policy.rs
index 09f033b0..34785b28 100644
--- a/sable_network/src/policy/standard_user_policy.rs
+++ b/sable_network/src/policy/standard_user_policy.rs
@@ -52,4 +52,8 @@ impl UserPolicyService for StandardUserPolicy {
 
         Err(PermissionError::User(Invisible))
     }
+
+    fn auto_attach_session(&self, _user: &wrapper::User) -> bool {
+        true
+    }
 }
diff --git a/sable_network/src/policy/user_policy.rs b/sable_network/src/policy/user_policy.rs
index bd76243f..eaa17bdc 100644
--- a/sable_network/src/policy/user_policy.rs
+++ b/sable_network/src/policy/user_policy.rs
@@ -5,9 +5,15 @@ use super::*;
 pub trait UserPolicyService {
     /// Determine whether a given user can set a given user mode on themselves
     fn can_set_umode(&self, user: &wrapper::User, mode: UserModeFlag) -> PermissionResult;
+
     /// Determine whether a given user can unset a given user mode on themselves
     fn can_unset_umode(&self, user: &wrapper::User, mode: UserModeFlag) -> PermissionResult;
+
     /// Determine whether one user can discover another without knowing their nick
     /// (eg. with `WHO *`)
     fn can_list_user(&self, touser: &User, user: &User) -> PermissionResult;
+
+    /// Determine whether a new connection of the given `user` will join an existing
+    /// session if there is any
+    fn auto_attach_session(&self, user: &wrapper::User) -> bool;
 }