From 9854caca331f6c85f4d76db47f8eb3d205fa7eee Mon Sep 17 00:00:00 2001
From: Evgeny <evgeny@poberezkin.com>
Date: Tue, 30 Sep 2025 12:34:42 +0100
Subject: [PATCH] agent: optimize subscriptions (#1645)

* agent: optimize subscriptions

* simplify

* clean up
---
 src/Simplex/Messaging/Agent.hs | 59 +++++++++++++++++++++-------------
 1 file changed, 37 insertions(+), 22 deletions(-)

diff --git a/src/Simplex/Messaging/Agent.hs b/src/Simplex/Messaging/Agent.hs
index 7193cb53d..c3f349b1d 100644
--- a/src/Simplex/Messaging/Agent.hs
+++ b/src/Simplex/Messaging/Agent.hs
@@ -1264,32 +1264,43 @@ type QSubResult = QCmdResult (Maybe SMP.ServiceId)
 subscribeConnections' :: AgentClient -> [ConnId] -> AM (Map ConnId (Either AgentErrorType (Maybe ClientServiceId)))
 subscribeConnections' _ [] = pure M.empty
 subscribeConnections' c connIds = do
-  conns :: Map ConnId (Either StoreError SomeConn) <- M.fromList . zip connIds <$> withStore' c (`getConns` connIds)
-  let (errs, cs) = M.mapEither id conns
-      errs' = M.map (Left . storeError) errs
-      (subRs, rcvQs) = M.mapEither rcvQueueOrResult cs
+  conns <- withStore' c (`getConns` connIds)
+  let (subRs, cs) = foldr partitionResultsConns ([], []) $ zip connIds conns
   resumeDelivery cs
-  resumeConnCmds c $ M.keys cs
-  rcvRs <- lift $ connResults . fst <$> subscribeQueues c (concat $ M.elems rcvQs)
+  resumeConnCmds c $ map fst cs
+  rcvRs <- lift $ connResults . fst <$> subscribeQueues c (concatMap rcvQueues cs)
   rcvRs' <- storeClientServiceAssocs rcvRs
   ns <- asks ntfSupervisor
   lift $ whenM (liftIO $ hasInstantNotifications ns) . void . forkIO . void $ sendNtfCreate ns rcvRs' cs
-  let rs = M.unions ([errs', subRs, rcvRs'] :: [Map ConnId (Either AgentErrorType (Maybe ClientServiceId))])
+  let rs = M.fromList subRs `M.union` rcvRs'
   notifyResultError rs
   pure rs
   where
-    rcvQueueOrResult :: SomeConn -> Either (Either AgentErrorType (Maybe ClientServiceId)) [RcvQueue]
-    rcvQueueOrResult (SomeConn _ conn) = case conn of
-      DuplexConnection _ rqs _ -> Right $ L.toList rqs
-      SndConnection _ sq -> Left $ sndSubResult sq
-      RcvConnection _ rq -> Right [rq]
-      ContactConnection _ rq -> Right [rq]
-      NewConnection _ -> Left (Right Nothing)
+    partitionResultsConns :: (ConnId, Either StoreError SomeConn) ->
+      ([(ConnId, Either AgentErrorType (Maybe ClientServiceId))], [(ConnId, SomeConn)]) ->
+      ([(ConnId, Either AgentErrorType (Maybe ClientServiceId))], [(ConnId, SomeConn)])
+    partitionResultsConns (connId, conn_) (rs, cs) = case conn_ of
+      Left e -> ((connId, Left (storeError e)) : rs, cs)
+      Right c'@(SomeConn _ conn) -> case conn of
+        DuplexConnection {} -> (rs, cs')
+        SndConnection _ sq -> ((connId, sndSubResult sq) : rs, cs')
+        RcvConnection _ _ -> (rs, cs')
+        ContactConnection _ _ -> (rs, cs')
+        NewConnection _ -> ((connId, Right Nothing) : rs, cs')
+        where
+          cs' = (connId, c') : cs
     sndSubResult :: SndQueue -> Either AgentErrorType (Maybe ClientServiceId)
     sndSubResult SndQueue {status} = case status of
       Confirmed -> Right Nothing
       Active -> Left $ CONN SIMPLEX "subscribeConnections"
       _ -> Left $ INTERNAL "unexpected queue status"
+    rcvQueues :: (ConnId, SomeConn) -> [RcvQueue]
+    rcvQueues (_, SomeConn _ conn) = case conn of
+      DuplexConnection _ rqs _ -> L.toList rqs
+      SndConnection {} -> []
+      RcvConnection _ rq -> [rq]
+      ContactConnection _ rq -> [rq]
+      NewConnection _ -> []
     connResults :: [(RcvQueue, Either AgentErrorType (Maybe SMP.ServiceId))] -> Map ConnId (Either AgentErrorType (Maybe SMP.ServiceId))
     connResults = M.map snd . foldl' addResult M.empty
       where
@@ -1308,21 +1319,25 @@ subscribeConnections' c connIds = do
     -- TODO [certs rcv] store associations of queues with client service ID
     storeClientServiceAssocs :: Map ConnId (Either AgentErrorType (Maybe SMP.ServiceId)) -> AM (Map ConnId (Either AgentErrorType (Maybe ClientServiceId)))
     storeClientServiceAssocs = pure . M.map (Nothing <$)
-    sendNtfCreate :: NtfSupervisor -> Map ConnId (Either AgentErrorType (Maybe ClientServiceId)) -> Map ConnId SomeConn -> AM' ()
+    sendNtfCreate :: NtfSupervisor -> Map ConnId (Either AgentErrorType (Maybe ClientServiceId)) -> [(ConnId, SomeConn)] -> AM' ()
     sendNtfCreate ns rcvRs cs = do
       let oks = M.keysSet $ M.filter (either temporaryAgentError $ const True) rcvRs
-          cs' = M.restrictKeys cs oks
-          (csCreate, csDelete) = M.partition (\(SomeConn _ conn) -> enableNtfs $ toConnData conn) cs'
+          (csCreate, csDelete) = foldr (groupConnIds oks) ([], []) cs
       sendNtfCmd NSCCreate csCreate
       sendNtfCmd NSCSmpDelete csDelete
       where
-        sendNtfCmd cmd cs' = forM_ (L.nonEmpty $ M.keys cs') $ \cids -> atomically $ writeTBQueue (ntfSubQ ns) (cmd, cids)
-    resumeDelivery :: Map ConnId SomeConn -> AM ()
+        groupConnIds oks (connId, SomeConn _ conn) acc@(csCreate, csDelete)
+          | connId `S.notMember` oks = acc
+          | enableNtfs (toConnData conn) = (connId : csCreate, csDelete)
+          | otherwise = (csCreate, connId : csDelete)
+        sendNtfCmd cmd = mapM_ (\cids -> atomically $ writeTBQueue (ntfSubQ ns) (cmd, cids)) . L.nonEmpty
+    resumeDelivery :: [(ConnId, SomeConn)] -> AM ()
     resumeDelivery conns = do
-      conns' <- M.restrictKeys conns . S.fromList <$> withStore' c getConnectionsForDelivery
+      deliverTo <- S.fromList <$> withStore' c getConnectionsForDelivery
+      let conns' = filter ((`S.member` deliverTo) . fst) conns
       lift $ mapM_ (mapM_ (\(cData, sqs) -> mapM_ (resumeMsgDelivery c cData) sqs) . sndQueue) conns'
-    sndQueue :: SomeConn -> Maybe (ConnData, NonEmpty SndQueue)
-    sndQueue (SomeConn _ conn) = case conn of
+    sndQueue :: (ConnId, SomeConn) -> Maybe (ConnData, NonEmpty SndQueue)
+    sndQueue (_, SomeConn _ conn) = case conn of
       DuplexConnection cData _ sqs -> Just (cData, sqs)
       SndConnection cData sq -> Just (cData, [sq])
       _ -> Nothing