feat(telegram): add Telegram group topic support

nanobot/channels/telegram.py

@@ -232,6 +232,10 @@ class TelegramChannel(BaseChannel):
         except ValueError:
             logger.error("Invalid chat_id: {}", msg.chat_id)
             return
+        message_thread_id = msg.metadata.get("message_thread_id")
+        thread_kwargs = {}
+        if message_thread_id is not None:
+            thread_kwargs["message_thread_id"] = message_thread_id
 
         reply_params = None
         if self.config.reply_to_message:
@@ -256,7 +260,8 @@ class TelegramChannel(BaseChannel):
                     await sender(
                         chat_id=chat_id,
                         **{param: f},
-                        reply_parameters=reply_params
+                        reply_parameters=reply_params,
+                        **thread_kwargs,
                     )
             except Exception as e:
                 filename = media_path.rsplit("/", 1)[-1]
@@ -264,7 +269,8 @@ class TelegramChannel(BaseChannel):
                 await self._app.bot.send_message(
                     chat_id=chat_id,
                     text=f"[Failed to send: {filename}]",
-                    reply_parameters=reply_params
+                    reply_parameters=reply_params,
+                    **thread_kwargs,
                 )
 
         # Send text content
@@ -276,7 +282,8 @@ class TelegramChannel(BaseChannel):
                         chat_id=chat_id,
                         text=html,
                         parse_mode="HTML",
-                        reply_parameters=reply_params
+                        reply_parameters=reply_params,
+                        **thread_kwargs,
                     )
                 except Exception as e:
                     logger.warning("HTML parse failed, falling back to plain text: {}", e)
@@ -284,7 +291,8 @@ class TelegramChannel(BaseChannel):
                         await self._app.bot.send_message(
                             chat_id=chat_id,
                             text=chunk,
-                            reply_parameters=reply_params
+                            reply_parameters=reply_params,
+                            **thread_kwargs,
                         )
                     except Exception as e2:
                         logger.error("Error sending Telegram message: {}", e2)
@@ -318,14 +326,39 @@ class TelegramChannel(BaseChannel):
         sid = str(user.id)
         return f"{sid}|{user.username}" if user.username else sid
 
+    @staticmethod
+    def _derive_topic_session_key(message) -> str | None:
+        """Derive topic-scoped session key for non-private Telegram chats."""
+        message_thread_id = getattr(message, "message_thread_id", None)
+        if message.chat.type == "private" or message_thread_id is None:
+            return None
+        return f"telegram:{message.chat_id}:topic:{message_thread_id}"
+
+    @staticmethod
+    def _build_message_metadata(message, user) -> dict:
+        """Build common Telegram inbound metadata payload."""
+        return {
+            "message_id": message.message_id,
+            "user_id": user.id,
+            "username": user.username,
+            "first_name": user.first_name,
+            "is_group": message.chat.type != "private",
+            "message_thread_id": getattr(message, "message_thread_id", None),
+            "is_forum": bool(getattr(message.chat, "is_forum", False)),
+        }
+
     async def _forward_command(self, update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
         """Forward slash commands to the bus for unified handling in AgentLoop."""
         if not update.message or not update.effective_user:
             return
+        message = update.message
+        user = update.effective_user
         await self._handle_message(
-            sender_id=self._sender_id(update.effective_user),
-            chat_id=str(update.message.chat_id),
-            content=update.message.text,
+            sender_id=self._sender_id(user),
+            chat_id=str(message.chat_id),
+            content=message.text,
+            metadata=self._build_message_metadata(message, user),
+            session_key=self._derive_topic_session_key(message),
         )
 
     async def _on_message(self, update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
@@ -407,6 +440,8 @@ class TelegramChannel(BaseChannel):
         logger.debug("Telegram message from {}: {}...", sender_id, content[:50])
 
         str_chat_id = str(chat_id)
+        metadata = self._build_message_metadata(message, user)
+        session_key = self._derive_topic_session_key(message)
 
         # Telegram media groups: buffer briefly, forward as one aggregated turn.
         if media_group_id := getattr(message, "media_group_id", None):
@@ -415,11 +450,8 @@ class TelegramChannel(BaseChannel):
                 self._media_group_buffers[key] = {
                     "sender_id": sender_id, "chat_id": str_chat_id,
                     "contents": [], "media": [],
-                    "metadata": {
-                        "message_id": message.message_id, "user_id": user.id,
-                        "username": user.username, "first_name": user.first_name,
-                        "is_group": message.chat.type != "private",
-                    },
+                    "metadata": metadata,
+                    "session_key": session_key,
                 }
                 self._start_typing(str_chat_id)
             buf = self._media_group_buffers[key]
@@ -439,13 +471,8 @@ class TelegramChannel(BaseChannel):
             chat_id=str_chat_id,
             content=content,
             media=media_paths,
-            metadata={
-                "message_id": message.message_id,
-                "user_id": user.id,
-                "username": user.username,
-                "first_name": user.first_name,
-                "is_group": message.chat.type != "private"
-            }
+            metadata=metadata,
+            session_key=session_key,
         )
 
     async def _flush_media_group(self, key: str) -> None:
@@ -459,6 +486,7 @@ class TelegramChannel(BaseChannel):
                 sender_id=buf["sender_id"], chat_id=buf["chat_id"],
                 content=content, media=list(dict.fromkeys(buf["media"])),
                 metadata=buf["metadata"],
+                session_key=buf.get("session_key"),
             )
         finally:
             self._media_group_tasks.pop(key, None)