impr: ignore message history in groups

bot/bot.py

@@ -196,15 +196,22 @@ async def _ask_question(
     logger.debug(f"Prepared question: {question}")
 
     user = UserData(context.user_data)
-    if is_follow_up:
-        # this is a follow-up question,
-        # so the bot should retain the previous history
-        history = user.messages.as_list()
+    if message.chat.type == Chat.PRIVATE:
+        # in private chats the bot remembers previous messages
+        if is_follow_up:
+            # this is a follow-up question,
+            # so the bot should retain the previous history
+            history = user.messages.as_list()
+        else:
+            # user is asking a question 'from scratch',
+            # so the bot should forget the previous history
+            user.messages.clear()
+            history = []
     else:
-        # user is asking a question 'from scratch',
-        # so the bot should forget the previous history
-        user.messages.clear()
-        history = []
+        # in group chats the bot only answers direct questions
+        # or follow-up questions to the bot messages
+        prev_message = questions.extract_prev(message, context)
+        history = [("", prev_message)] if prev_message else []
 
     chat = ChatData(context.chat_data)
     start = time.perf_counter_ns()

bot/questions.py

@@ -42,7 +42,9 @@ def extract_group(message: Message, context: CallbackContext) -> tuple[str, Mess
 
     # the message is mentioning the bot,
     # so remove the mention to get the question
-    question = message.text[: mention.offset] + message.text[mention.offset + mention.length :]
+    question = (
+        message.text[: mention.offset] + message.text[mention.offset + mention.length :]
+    )
     question = question.strip()
 
     # messages in topics are technically replies to the 'topic created' message
@@ -59,6 +61,19 @@ def extract_group(message: Message, context: CallbackContext) -> tuple[str, Mess
     return question, message
 
 
+def extract_prev(message: Message, context: CallbackContext) -> str:
+    """Extracts the previous message by the bot, if any."""
+    if (
+        message.reply_to_message
+        and message.reply_to_message.from_user.username == context.bot.username
+    ):
+        # treat a reply to the bot as a follow-up question
+        return message.reply_to_message.text
+
+    # otherwise, ignore previous messages
+    return ""
+
+
 def prepare(question: str) -> tuple[str, bool]:
     """
     Returns the question without the special commands