app.py

import os
import asyncio
import gradio as gr
from openai import AsyncOpenAI

# Fetch the API key from Hugging Face Spaces Secrets
OPENROUTER_API_KEY = os.environ.get("API_KEY")

# Initialize the ASYNC client targeting OpenRouter
client = AsyncOpenAI(
    base_url="https://openrouter.ai",
    api_key=OPENROUTER_API_KEY,
)

# Using 'async def' properly handles streaming under Python 3.13
async def predict(message, history):
    if not OPENROUTER_API_KEY:
        yield "Error: API_KEY secret is missing in Hugging Face Space settings."
        return

    # Clean up history: Modern Gradio can include system blocks or objects.
    # OpenRouter requires only raw 'user' and 'assistant' text roles.
    cleaned_messages = []
    if history:
        for msg in history:
            role = msg.get("role")
            content = msg.get("content")
            # Only append standard text conversations
            if role in ["user", "assistant"] and isinstance(content, str):
                cleaned_messages.append({"role": role, "content": content})

    # Append the new user prompt
    cleaned_messages.append({"role": "user", "content": message})

    try:
        # Request an async stream from OpenRouter
        response = await client.chat.completions.create(
            model="meta-llama/llama-3-8b-instruct:free",
            messages=cleaned_messages,
            stream=True
        )

        # Async generator prevents the StopAsyncIteration crash entirely
        partial_message = ""
        async for chunk in response:
            if chunk.choices and chunk.choices[0].delta.content:
                partial_message += chunk.choices[0].delta.content
                yield partial_message
                
    except Exception as e:
        yield f"An error occurred while connecting to OpenRouter: {str(e)}"

# Define the ChatInterface cleanly
demo = gr.ChatInterface(
    fn=predict,
    title="OpenRouter Chatbot",
    description="Running safely on the absolute latest version of Gradio and Python 3.13.",
)

if __name__ == "__main__":
    demo.launch(ssr_mode=False)