fix the async generator issue and improve the chat interface:

app.py

@@ -364,7 +364,7 @@ def convert_to_messages_format(chat_history):
     
     return messages
 
-async def stream_agent_response(question: str, chat_history: List) -> tuple:
+async def stream_agent_response(question: str, chat_history: List) -> List[Dict]:
     """Procesa la pregunta del usuario y devuelve la respuesta del agente."""
     # Initialize response
     response_text = ""
@@ -375,7 +375,8 @@ async def stream_agent_response(question: str, chat_history: List) -> tuple:
         messages.extend(chat_history)
     
     # Add user's question
-    messages.append({"role": "user", "content": question})
+    user_message = {"role": "user", "content": question}
+    messages.append(user_message)
     
     if not agent:
         error_msg = (
@@ -386,16 +387,20 @@ async def stream_agent_response(question: str, chat_history: List) -> tuple:
             f"3. El modelo de lenguaje esté disponible\n\n"
             f"Error: {agent_error}"
         )
-        messages.append({"role": "assistant", "content": error_msg})
-        yield messages
-        return
+        assistant_message = {"role": "assistant", "content": error_msg}
+        messages.append(assistant_message)
+        return [assistant_message]
     
     try:
+        # Add empty assistant message that will be updated
+        assistant_message = {"role": "assistant", "content": ""}
+        messages.append(assistant_message)
+        
         # Execute the agent
         response = await agent.ainvoke({"input": question, "chat_history": chat_history})
         
         # Process the response
-        if hasattr(response, 'output'):
+        if hasattr(response, 'output') and response.output:
             response_text = response.output
             
             # Check if the response contains an SQL query
@@ -408,19 +413,25 @@ async def stream_agent_response(question: str, chat_history: List) -> tuple:
                     response_text += f"\n\n### 🔍 Resultado de la consulta:\n```sql\n{sql_query}\n```\n\n{query_result}"
                 else:
                     response_text += "\n\n⚠️ No se pudo conectar a la base de datos para ejecutar la consulta."
+            
+            # Update the assistant's message with the response
+            assistant_message["content"] = response_text
+            
         else:
-            response_text = "Error: No se recibió respuesta del agente."
-        
-        # Add assistant's response to the chat history
-        messages.append({"role": "assistant", "content": response_text})
+            assistant_message["content"] = "Error: No se recibió respuesta del agente."
         
-        # Yield the updated messages
-        yield messages
+        # Return the assistant's message
+        return [assistant_message]
         
     except Exception as e:
         error_msg = f"## ❌ Error\n\nOcurrió un error al procesar tu solicitud:\n\n```\n{str(e)}\n```"
-        messages.append({"role": "assistant", "content": error_msg})
-        yield messages
+        if "assistant_message" in locals():
+            assistant_message["content"] = error_msg
+        else:
+            assistant_message = {"role": "assistant", "content": error_msg}
+        
+        logger.error(f"Error in stream_agent_response: {str(e)}", exc_info=True)
+        return [assistant_message]
 
 # Custom CSS for the app
 custom_css = """
@@ -643,24 +654,26 @@ def create_application():
     async def bot_response(chat_history: List[Dict]) -> List[Dict]:
         """Get bot response and update chat history."""
         if not chat_history or chat_history[-1]["role"] != "assistant":
-            return chat_history
+            yield chat_history
+            return
         
         try:
             # Get the user's question (second to last message)
             if len(chat_history) < 2:
-                return chat_history
+                yield chat_history
+                return
                 
             question = chat_history[-2]["content"]
             logger.info(f"Processing question: {question}")
             
             # Call the agent and stream the response
             async for response in stream_agent_response(question, chat_history[:-2]):
-                if isinstance(response, tuple) and len(response) > 0 and isinstance(response[0], list):
-                    messages = response[0]
-                    if messages and messages[-1]["role"] == "assistant":
-                        # Update the assistant's response
-                        chat_history[-1] = messages[-1]
-                        yield chat_history
+                if isinstance(response, list):
+                    for msg in response:
+                        if msg["role"] == "assistant":
+                            # Update the assistant's response
+                            chat_history[-1] = msg
+                            yield chat_history
             
             logger.info("Response generation complete")