WIP: add batching

src/Simplex/Chat.hs

@@ -1,8 +1,11 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE GADTs #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE MultiWayIf #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedRecordDot #-}
@@ -4989,9 +4992,10 @@ processAgentMessageConn user@User {userId} corrId agentConnId agentMessage = do
             Left _ -> messageError "x.grp.mem.inv error: referenced member does not exist"
             Right reMember -> do
               GroupMemberIntro {introId} <- withStore $ \db -> saveIntroInvitation db reMember m introInv
-              void . sendGroupMessage' user [reMember] (XGrpMemFwd (memberInfo m) introInv) groupId (Just introId) $
-                withStore' $
-                  \db -> updateIntroStatus db introId GMIntroInvForwarded
+              void . runDBSuspendingChat_ $ sendGroupMessage' user [reMember] (XGrpMemFwd (memberInfo m) introInv) groupId (Just introId) $
+                -- withStore' $ \db ->
+                suspendDB $ \db ->
+                  updateIntroStatus db introId GMIntroInvForwarded
         _ -> messageError "x.grp.mem.inv can be only sent by invitee member"
 
     xGrpMemFwd :: GroupInfo -> GroupMember -> MemberInfo -> IntroInvitation -> m ()
@@ -5522,11 +5526,91 @@ deliverMessage conn@Connection {connId} cmEventTag msgBody msgId = do
   let sndMsgDelivery = SndMsgDelivery {connId, agentMsgId}
   withStore' $ \db -> createSndMsgDelivery db sndMsgDelivery msgId
 
+newtype Sus i a = Sus
+  { runSus :: ReaderT (TVar [i], ChatController) IO a
+  } deriving (Functor, Applicative, Monad, MonadIO, MonadUnliftIO)
+
+-- Recover MonadError via MonadUnliftIO
+instance MonadError ChatError (Sus i) where
+  throwError = E.throwIO
+  {-# INLINE throwError #-}
+  catchError = E.catch
+  {-# INLINE catchError #-}
+
+-- Alas, there's no MonadCont IO, and no MonadUnliftIO (ContT IO)
+-- instance MonadCont Sus where
+--   callCC a'susB_susA = Sus $ do
+--     callCC $ \a'rB ->
+--       let Sus s = a'susB_susA $ \a -> Sus (a'rB a)
+--       in s
+
+-- Hide our extra state var from ChatMonad/Reader
+instance MonadReader ChatController (Sus i) where
+  ask = Sus $ asks snd
+  {-# INLINE ask #-}
+  local f (Sus action) = Sus $ local (fmap f) action
+  {-# INLINE local #-}
+
+-- Instantiate TVar-powered MonadState, breaking atomic updates
+-- instance MonadState [IO ()] Sus where
+--   state f = Sus $ asks fst >>= \st -> atomically (stateTVar st f)
+--   get = Sus $ asks fst >>= readTVarIO
+--   put x = seq x $ Sus $ asks fst >>= \st -> atomically (writeTVar st x)
+
+-- Or not... just use our hidden state directly
+suspend :: i -> Sus i ()
+suspend action = Sus $ asks fst >>= \st -> atomically $ modifyTVar' st (action :) -- XXX: pushing actions to a stack - reverse to get original order (if needed)
+{-# INLINE suspend #-}
+
+-- Make it classy to prevent monomorphization of ChatMonad constraints
+class SuspendIO m where
+  suspendIO :: IO () -> m ()
+
+instance SuspendIO (Sus (IO ())) where
+  suspendIO = suspend
+
+suspendM :: (MonadUnliftIO m, SuspendIO m) => m () -> m ()
+suspendM action = toIO action >>= suspendIO
+
+-- Boo, does not aggregate transactions
+-- withStoreLater :: (ChatMonad m, SuspendIO m) => (DB.Connection -> IO ()) -> m ()
+-- withStoreLater action = suspendM (withStore' action)
+
+withStoreLater :: SuspendDB m => (DB.Connection -> IO ()) -> m ()
+withStoreLater = suspendDB
+
+class SuspendDB m where
+  suspendDB :: (DB.Connection -> IO ()) -> m ()
+
+instance SuspendDB (Sus (DB.Connection -> IO ())) where
+  suspendDB = suspend
+
+runSuspendingChat :: ChatMonad m => ([i] -> m r) -> Sus i  a -> m (r, a)
+runSuspendingChat animate (Sus action) = do
+  cc <- ask
+  suspended <- newTVarIO []
+  r <- E.try (liftIO $ runReaderT action (suspended, cc)) >>= liftEither
+  readTVarIO suspended >>= animate >>= \susResults -> pure (susResults, r)
+
+runIOSuspendingChat_ :: forall m a . ChatMonad m => Sus (IO ()) a -> m a
+runIOSuspendingChat_ action = snd <$> runSuspendingChat animate_ action
+  where
+    animate_ :: [IO ()] -> m ()
+    animate_ = mapM_ liftIO
+
+runDBSuspendingChat_ :: forall m a . ChatMonad m => Sus (DB.Connection -> IO ()) a -> m a
+runDBSuspendingChat_ action = snd <$> runSuspendingChat animate action
+  where
+    animate :: [DB.Connection -> IO ()] -> m ()
+    animate batch = withStore' $ \db -> mapM_ ($ db) $ reverse batch -- XXX: recover original order from consing to []
+
 sendGroupMessage :: (MsgEncodingI e, ChatMonad m) => User -> GroupInfo -> [GroupMember] -> ChatMsgEvent e -> m (SndMessage, [GroupMember])
 sendGroupMessage user GroupInfo {groupId} members chatMsgEvent =
-  sendGroupMessage' user members chatMsgEvent groupId Nothing $ pure ()
+  -- Give SuspendDB powers
+  runDBSuspendingChat_ $ sendGroupMessage' user members chatMsgEvent groupId Nothing $ pure ()
 
-sendGroupMessage' :: forall e m. (MsgEncodingI e, ChatMonad m) => User -> [GroupMember] -> ChatMsgEvent e -> Int64 -> Maybe Int64 -> m () -> m (SndMessage, [GroupMember])
+-- Require SuspendDB powers
+sendGroupMessage' :: forall e m. (MsgEncodingI e, ChatMonad m, SuspendDB m) => User -> [GroupMember] -> ChatMsgEvent e -> Int64 -> Maybe Int64 -> m () -> m (SndMessage, [GroupMember])
 sendGroupMessage' user members chatMsgEvent groupId introId_ postDeliver = do
   msg <- createSndMessage chatMsgEvent (GroupId groupId)
   -- TODO collect failed deliveries into a single error
@@ -5551,7 +5635,7 @@ sendGroupMessage' user members chatMsgEvent groupId introId_ postDeliver = do
           | forwardSupported && isForwardedGroupMsg chatMsgEvent = pure Nothing
           | isXGrpMsgForward chatMsgEvent = pure Nothing
           | otherwise = do
-              withStore' $ \db -> createPendingGroupMessage db groupMemberId msgId introId_
+              withStoreLater $ \db -> createPendingGroupMessage db groupMemberId msgId introId_
               pure $ Just m
         forwardSupported = do
           let mcvr = memberChatVRange' m