feat: Implement event rejection

Co-Authored-By: star <star@nexy7574.co.uk>

src/admin/user/commands.rs

@@ -763,6 +763,41 @@ pub(super) async fn force_join_room(
 		.await
 }
 
+#[admin_command]
+pub(super) async fn force_join_room_remotely(
+	&self,
+	user_id: String,
+	room_id: OwnedRoomOrAliasId,
+	via: String,
+) -> Result {
+	let via = ServerName::parse(&via)?;
+	let user_id = parse_local_user_id(self.services, &user_id)?;
+	let (room_id, mut servers) = self
+		.services
+		.rooms
+		.alias
+		.resolve_with_servers(&room_id, None)
+		.await?;
+	if servers.contains(&via) {
+		servers.retain(|n| *n != via);
+	}
+	servers.insert(0, via);
+
+	assert!(
+		self.services.globals.user_is_local(&user_id),
+		"Parsed user_id must be a local user"
+	);
+	let state_lock = self.services.rooms.state.mutex.lock(&*room_id).await;
+	self.services
+		.rooms
+		.membership
+		.join_remote_room(&user_id, &room_id, None, &servers, state_lock)
+		.await?;
+
+	self.write_str(&format!("{user_id} has been joined to {room_id}."))
+		.await
+}
+
 #[admin_command]
 pub(super) async fn force_leave_room(
 	&self,

src/admin/user/mod.rs

@@ -183,6 +183,20 @@ pub enum UserCommand {
 		room_id: OwnedRoomOrAliasId,
 	},
 
+	/// Manually join a local user to a room via a remote server, regardless of
+	/// our current residency.
+	ForceJoinRoomRemotely {
+		/// The user to join
+		user_id: String,
+		/// The room to join
+		room_id: OwnedRoomOrAliasId,
+		/// The server name to join via.
+		///
+		/// This server will always be tried first, however if more are
+		/// available, they may be tried after.
+		via: String,
+	},
+
 	/// Manually leave a local user from a room.
 	ForceLeaveRoom {
 		user_id: String,