Improve history handling

- Try to keep at least 3 messages from each channel in the history
- Use post processed messages for the history, instead of the raw
  messages from the openai API

fjerkroa_bot/ai_responder.py

@@ -97,13 +97,12 @@ class AIResponder(object):
         system = system.replace('{date}', time.strftime('%Y-%m-%d'))\
                        .replace('{time}', time.strftime('%H:%M:%S'))
         messages.append({"role": "system", "content": system})
-        if limit is None:
-            history = self.history[:]
-        else:
-            history = self.history[-limit:]
-        history.append({"role": "user", "content": str(message)})
-        for msg in history:
+        if limit is not None:
+            while len(self.history) > limit:
+                self.shrink_history_by_one()
+        for msg in self.history:
             messages.append(msg)
+        messages.append({"role": "user", "content": str(message)})
         return messages
 
     async def draw(self, description: str) -> BytesIO:
@@ -202,11 +201,22 @@ class AIResponder(object):
             logging.warning(f"failed to execute a fix for the answer: {repr(err)}")
         return answer
 
+    def shrink_history_by_one(self, index: int = 0) -> None:
+        if index >= len(self.history):
+            del self.history[0]
+        else:
+            current = self.history[index]
+            count = sum(1 for item in self.history[index:] if item.get('channel') == current.get('channel'))
+            if count > 3:
+                del self.history[index]
+            else:
+                self.shrink_history_by_one(index + 1)
+
     def update_history(self, question: Dict[str, Any], answer: Dict[str, Any], limit: int) -> None:
         self.history.append(question)
         self.history.append(answer)
-        if len(self.history) > limit:
-            self.history = self.history[-limit:]
+        while len(self.history) > limit:
+            self.shrink_history_by_one()
         if self.history_file is not None:
             with open(self.history_file, 'wb') as fd:
                 pickle.dump(self.history, fd)
@@ -236,8 +246,9 @@ class AIResponder(object):
             if 'hack' not in response or type(response.get('picture', None)) not in (type(None), str):
                 retries -= 1
                 continue
-            self.update_history(messages[-1], answer, limit)
             answer_message = await self.post_process(message, response)
+            answer['content'] = str(answer_message)
+            self.update_history(messages[-1], answer, limit)
             logging.info(f"got this answer:\n{str(answer_message)}")
             return answer_message
         raise RuntimeError("Failed to generate answer after multiple retries")