fix telegram streaming message boundaries

nanobot/channels/telegram.py

@@ -12,7 +12,7 @@ from typing import Any, Literal
 from loguru import logger
 from pydantic import Field
 from telegram import BotCommand, ReactionTypeEmoji, ReplyParameters, Update
-from telegram.error import TimedOut
+from telegram.error import BadRequest, TimedOut
 from telegram.ext import Application, CommandHandler, ContextTypes, MessageHandler, filters
 from telegram.request import HTTPXRequest
 
@@ -163,6 +163,7 @@ class _StreamBuf:
     text: str = ""
     message_id: int | None = None
     last_edit: float = 0.0
+    stream_id: str | None = None
 
 
 class TelegramConfig(Base):
@@ -478,17 +479,24 @@ class TelegramChannel(BaseChannel):
                 logger.error("Error sending Telegram message: {}", e2)
                 raise
 
+    @staticmethod
+    def _is_not_modified_error(exc: Exception) -> bool:
+        return isinstance(exc, BadRequest) and "message is not modified" in str(exc).lower()
+
     async def send_delta(self, chat_id: str, delta: str, metadata: dict[str, Any] | None = None) -> None:
         """Progressive message editing: send on first delta, edit on subsequent ones."""
         if not self._app:
             return
         meta = metadata or {}
         int_chat_id = int(chat_id)
+        stream_id = meta.get("_stream_id")
 
         if meta.get("_stream_end"):
             buf = self._stream_bufs.get(chat_id)
             if not buf or not buf.message_id or not buf.text:
                 return
+            if stream_id is not None and buf.stream_id is not None and buf.stream_id != stream_id:
+                return
             self._stop_typing(chat_id)
             try:
                 html = _markdown_to_telegram_html(buf.text)
@@ -498,6 +506,10 @@ class TelegramChannel(BaseChannel):
                     text=html, parse_mode="HTML",
                 )
             except Exception as e:
+                if self._is_not_modified_error(e):
+                    logger.debug("Final stream edit already applied for {}", chat_id)
+                    self._stream_bufs.pop(chat_id, None)
+                    return
                 logger.debug("Final stream edit failed (HTML), trying plain: {}", e)
                 try:
                     await self._call_with_retry(
@@ -506,15 +518,21 @@ class TelegramChannel(BaseChannel):
                         text=buf.text,
                     )
                 except Exception as e2:
+                    if self._is_not_modified_error(e2):
+                        logger.debug("Final stream plain edit already applied for {}", chat_id)
+                        self._stream_bufs.pop(chat_id, None)
+                        return
                     logger.warning("Final stream edit failed: {}", e2)
                     raise  # Let ChannelManager handle retry
             self._stream_bufs.pop(chat_id, None)
             return
 
         buf = self._stream_bufs.get(chat_id)
-        if buf is None:
-            buf = _StreamBuf()
+        if buf is None or (stream_id is not None and buf.stream_id is not None and buf.stream_id != stream_id):
+            buf = _StreamBuf(stream_id=stream_id)
             self._stream_bufs[chat_id] = buf
+        elif buf.stream_id is None:
+            buf.stream_id = stream_id
         buf.text += delta
 
         if not buf.text.strip():
@@ -541,6 +559,9 @@ class TelegramChannel(BaseChannel):
                 )
                 buf.last_edit = now
             except Exception as e:
+                if self._is_not_modified_error(e):
+                    buf.last_edit = now
+                    return
                 logger.warning("Stream edit failed: {}", e)
                 raise  # Let ChannelManager handle retry