core: support batch sending in groups, batch introductions; send recent message history to new members (#3519)

* core: batch send stubs, comments

* multiple events in ChatMessage and supporting types

* Revert "multiple events in ChatMessage and supporting types"

This reverts commit 9b239b26ba.

* schema, refactor group processing for batched messages

* encoding, refactor processing

* refactor code to work with updated schema

* encoding, remove instances

* wip

* implement batching

* batch introductions

* wip

* collect and send message history

* missing new line

* rename

* test

* rework to build history via chat items

* refactor, tests

* correctly set member version range, dont include deleted items

* tests

* fix disappearing messages

* check number of errors

* comment

* check size in encodeChatMessage

* fix - don't check msg size for binary

* use builder

* rename

* rename

* rework batching

* lazy msg body

* use withStoreBatch

* refactor

* reverse batches

* comment

* possibly fix builder for single msg

* refactor batcher

* refactor

* dont repopulate msg_deliveries on down migration

* EncodedChatMessage type

* remove type

* batcher tests

* add tests

* group history preference

* test group link

* fix tests

* fix for random update

* add test testImageFitsSingleBatch

* refactor

* rename function

* refactor

* mconcat

* rename feature

* catch error on each batch

* refactor file inv retrieval

* refactor gathering item forward events

* refactor message batching

* unite migrations

* move files

* refactor

* Revert "unite migrations"

This reverts commit 0be7a3117a.

* refactor splitFileDescr

* improve tests

* Revert "dont repopulate msg_deliveries on down migration"

This reverts commit 2944c1cc28.

* fix down migration

---------

Co-authored-by: Evgeny Poberezkin <2769109+epoberezkin@users.noreply.github.com>

src/Simplex/Chat/Util.hs

@@ -1,12 +1,18 @@
-module Simplex.Chat.Util (week, encryptFile, chunkSize) where
+{-# LANGUAGE TupleSections #-}
+
+module Simplex.Chat.Util (week, encryptFile, chunkSize, shuffle) where
 
 import Control.Monad
 import Control.Monad.Except
 import Control.Monad.IO.Class
 import qualified Data.ByteString.Lazy as LB
+import Data.List (sortBy)
+import Data.Ord (comparing)
 import Data.Time (NominalDiffTime)
+import Data.Word (Word16)
 import Simplex.Messaging.Crypto.File (CryptoFile (..), CryptoFileArgs (..))
 import qualified Simplex.Messaging.Crypto.File as CF
+import System.Random (randomRIO)
 import UnliftIO.IO (IOMode (..), withFile)
 
 week :: NominalDiffTime
@@ -30,3 +36,9 @@ encryptFile fromPath toPath cfArgs = do
 chunkSize :: Num a => a
 chunkSize = 65536
 {-# INLINE chunkSize #-}
+
+shuffle :: [a] -> IO [a]
+shuffle xs = map snd . sortBy (comparing fst) <$> mapM (\x -> (,x) <$> random) xs
+  where
+    random :: IO Word16
+    random = randomRIO (0, 65535)