telegram: add group chat support

- Only respond in groups when @mentioned or replied to
- Add ChatType to TelegramMessage (private/group/supergroup/channel)
- Add getMe API call to fetch bot username on startup
- Add shouldRespondInGroup helper function

2 files changed, 86 insertions, 4 deletions

diff --git a/Omni/Agent/Telegram.hs b/Omni/Agent/Telegram.hs
index c55dc5a..ffad4c7 100644
--- a/Omni/Agent/Telegram.hs
+++ b/Omni/Agent/Telegram.hs
@@ -184,6 +184,29 @@ getUpdates cfg offset = do
           _ -> pure []
         _ -> pure []
 
+getBotUsername :: Types.TelegramConfig -> IO (Maybe Text)
+getBotUsername cfg = do
+  let url =
+        Text.unpack (Types.tgApiBaseUrl cfg)
+          <> "/bot"
+          <> Text.unpack (Types.tgBotToken cfg)
+          <> "/getMe"
+  result <-
+    try <| do
+      req <- HTTP.parseRequest url
+      HTTP.httpLBS req
+  case result of
+    Left (_ :: SomeException) -> pure Nothing
+    Right response -> do
+      let body = HTTP.getResponseBody response
+      case Aeson.decode body of
+        Just (Aeson.Object obj) -> case KeyMap.lookup "result" obj of
+          Just (Aeson.Object userObj) -> case KeyMap.lookup "username" userObj of
+            Just (Aeson.String username) -> pure (Just username)
+            _ -> pure Nothing
+          _ -> pure Nothing
+        _ -> pure Nothing
+
 sendMessage :: Types.TelegramConfig -> Int -> Text -> IO ()
 sendMessage cfg chatId text = do
   let url =
@@ -231,6 +254,12 @@ runTelegramBot tgConfig provider = do
   putText "Starting Telegram bot..."
   offsetVar <- newTVarIO 0
 
+  botUsername <- getBotUsername tgConfig
+  case botUsername of
+    Nothing -> putText "Warning: could not get bot username, group mentions may not work"
+    Just name -> putText <| "Bot username: @" <> name
+  let botName = fromMaybe "bot" botUsername
+
   _ <- forkIO (reminderLoop tgConfig)
   putText "Reminder loop started (checking every 5 minutes)"
 
@@ -249,28 +278,34 @@ runTelegramBot tgConfig provider = do
     messages <- getUpdates tgConfig offset
     forM_ messages <| \msg -> do
       atomically (writeTVar offsetVar (Types.tmUpdateId msg + 1))
-      handleMessage tgConfig provider engineCfg msg
+      handleMessage tgConfig provider engineCfg botName msg
     when (null messages) <| threadDelay 1000000
 
 handleMessage ::
   Types.TelegramConfig ->
   Provider.Provider ->
   Engine.EngineConfig ->
+  Text ->
   Types.TelegramMessage ->
   IO ()
-handleMessage tgConfig provider engineCfg msg = do
+handleMessage tgConfig provider engineCfg botUsername msg = do
   let userName =
         Types.tmUserFirstName msg
           <> maybe "" (" " <>) (Types.tmUserLastName msg)
       chatId = Types.tmChatId msg
       usrId = Types.tmUserId msg
 
+  unless (Types.shouldRespondInGroup botUsername msg) <| do
+    when (Types.isGroupChat msg)
+      <| putText
+      <| "Ignoring group message (not mentioned): "
+      <> Text.take 50 (Types.tmText msg)
+
   unless (Types.isUserAllowed tgConfig usrId) <| do
     putText <| "Unauthorized user: " <> tshow usrId <> " (" <> userName <> ")"
     sendMessage tgConfig chatId "sorry, you're not authorized to use this bot."
-    pure ()
 
-  when (Types.isUserAllowed tgConfig usrId) <| do
+  when (Types.shouldRespondInGroup botUsername msg && Types.isUserAllowed tgConfig usrId) <| do
     sendTypingAction tgConfig chatId
 
     user <- Memory.getOrCreateUserByTelegramId usrId userName
diff --git a/Omni/Agent/Telegram/Types.hs b/Omni/Agent/Telegram/Types.hs
index 2db6a52..d240786 100644
--- a/Omni/Agent/Telegram/Types.hs
+++ b/Omni/Agent/Telegram/Types.hs
@@ -19,6 +19,7 @@ module Omni.Agent.Telegram.Types
     TelegramPhoto (..),
     TelegramVoice (..),
     TelegramReplyMessage (..),
+    ChatType (..),
 
     -- * Parsing
     parseUpdate,
@@ -31,6 +32,8 @@ module Omni.Agent.Telegram.Types
     -- * Utilities
     isPdf,
     isSupportedVoiceFormat,
+    isGroupChat,
+    shouldRespondInGroup,
 
     -- * Testing
     main,
@@ -81,6 +84,7 @@ test =
               TelegramMessage
                 { tmUpdateId = 123,
                   tmChatId = 456,
+                  tmChatType = Private,
                   tmUserId = 789,
                   tmUserFirstName = "Test",
                   tmUserLastName = Just "User",
@@ -319,9 +323,28 @@ instance Aeson.FromJSON TelegramReplyMessage where
         <*> (v .:? "from_last_name")
         <*> (v .:? "text" .!= "")
 
+data ChatType = Private | Group | Supergroup | Channel
+  deriving (Show, Eq, Generic)
+
+instance Aeson.ToJSON ChatType where
+  toJSON Private = Aeson.String "private"
+  toJSON Group = Aeson.String "group"
+  toJSON Supergroup = Aeson.String "supergroup"
+  toJSON Channel = Aeson.String "channel"
+
+instance Aeson.FromJSON ChatType where
+  parseJSON = Aeson.withText "ChatType" parseChatType
+    where
+      parseChatType "private" = pure Private
+      parseChatType "group" = pure Group
+      parseChatType "supergroup" = pure Supergroup
+      parseChatType "channel" = pure Channel
+      parseChatType _ = pure Private
+
 data TelegramMessage = TelegramMessage
   { tmUpdateId :: Int,
     tmChatId :: Int,
+    tmChatType :: ChatType,
     tmUserId :: Int,
     tmUserFirstName :: Text,
     tmUserLastName :: Maybe Text,
@@ -338,6 +361,7 @@ instance Aeson.ToJSON TelegramMessage where
     Aeson.object
       [ "update_id" .= tmUpdateId m,
         "chat_id" .= tmChatId m,
+        "chat_type" .= tmChatType m,
         "user_id" .= tmUserId m,
         "user_first_name" .= tmUserFirstName m,
         "user_last_name" .= tmUserLastName m,
@@ -353,6 +377,7 @@ instance Aeson.FromJSON TelegramMessage where
     Aeson.withObject "TelegramMessage" <| \v ->
       (TelegramMessage </ (v .: "update_id"))
         <*> (v .: "chat_id")
+        <*> (v .:? "chat_type" .!= Private)
         <*> (v .: "user_id")
         <*> (v .: "user_first_name")
         <*> (v .:? "user_last_name")
@@ -385,6 +410,12 @@ parseUpdate val = do
   chatId <- case KeyMap.lookup "id" chatObj of
     Just (Aeson.Number n) -> Just (round n)
     _ -> Nothing
+  let chatType = case KeyMap.lookup "type" chatObj of
+        Just (Aeson.String "private") -> Private
+        Just (Aeson.String "group") -> Group
+        Just (Aeson.String "supergroup") -> Supergroup
+        Just (Aeson.String "channel") -> Channel
+        _ -> Private
   Aeson.Object fromObj <- KeyMap.lookup "from" msgObj
   userId <- case KeyMap.lookup "id" fromObj of
     Just (Aeson.Number n) -> Just (round n)
@@ -419,6 +450,7 @@ parseUpdate val = do
     TelegramMessage
       { tmUpdateId = updateId,
         tmChatId = chatId,
+        tmChatType = chatType,
         tmUserId = userId,
         tmUserFirstName = firstName,
         tmUserLastName = lastName,
@@ -547,3 +579,18 @@ isSupportedVoiceFormat voice =
     Just "audio/x-opus+ogg" -> True
     Nothing -> True
     _ -> False
+
+isGroupChat :: TelegramMessage -> Bool
+isGroupChat msg = tmChatType msg `elem` [Group, Supergroup]
+
+shouldRespondInGroup :: Text -> TelegramMessage -> Bool
+shouldRespondInGroup botUsername msg
+  | not (isGroupChat msg) = True
+  | isMentioned = True
+  | isReplyToBot = True
+  | otherwise = False
+  where
+    msgText = Text.toLower (tmText msg)
+    mention = "@" <> Text.toLower botUsername
+    isMentioned = mention `Text.isInfixOf` msgText
+    isReplyToBot = isJust (tmReplyTo msg)