app.py

import os
import asyncio
import logging
from dotenv import load_dotenv
import chainlit as cl

# Set up logging
logging.basicConfig(level=logging.INFO)

# Attempt to import google.generativeai (optional dependency)
try:
    import google.generativeai as genai
except ImportError:
    genai = None
    logging.warning("google.generativeai not installed or failed to import. Gemini will be unavailable.")

# Load .env (won't override Space secrets)
load_dotenv()

# Read config
GOOGLE_API_KEY = os.getenv("GOOGLE_API_KEY")
MODEL_NAME = os.getenv("MODEL_NAME", "gemini-2.0-flash")

# Try to configure Gemini if possible
model = None
if genai is not None:
    if GOOGLE_API_KEY:
        try:
            genai.configure(api_key=GOOGLE_API_KEY)
            model = genai.GenerativeModel(MODEL_NAME)
            logging.info(f"Gemini model initialized: {MODEL_NAME}")
        except Exception as e:
            logging.error(f"Failed to initialize Gemini model '{MODEL_NAME}': {e}")
else:
    logging.error("google.generativeai is not available.")

SYSTEM_PROMPT = "You are a helpful assistant."

async def _call_gemini_generate(prompt: str):
    """Run Gemini generate_content in a background thread."""
    if model is None:
        raise RuntimeError("Gemini model not initialized")
    return await asyncio.to_thread(model.generate_content, prompt)

@cl.on_chat_start
async def on_chat_start():
    """Welcome message and session init."""
    cl.user_session.set("message_history", [{"role": "system", "content": SYSTEM_PROMPT}])
    
    if model is None:
        await cl.Message(
            content=(
                "Hello — the app is running. Gemini is not available because GOOGLE_API_KEY is not set or the model failed to init.\n\n"
                "Owner action: add a `GOOGLE_API_KEY` secret in Space Settings and rebuild the Space.\n\n"
                "You can still test the chat using the echo fallback below."
            )
        ).send()
    else:
        await cl.Message(content="Hello — Gemini bot ready. Ask me anything!").send()

@cl.on_message
async def handle_message(message: cl.Message):
    user_text = (message.content or "").strip()
    if not user_text:
        await cl.Message(content="Please type a question or prompt.").send()
        return

    # Store message in session history
    history = cl.user_session.get("message_history", [])
    history.append({"role": "user", "content": user_text})
    cl.user_session.set("message_history", history)

    # Send a progress message
    progress = cl.Message(content="(Thinking...)")
    await progress.send()

    if model is None:
        reply = (
            "Gemini not initialized (GOOGLE_API_KEY missing or model failed to init).\n\n"
            "Echoing your input:\n\n" + user_text + "\n\n"
            "To enable Gemini responses: open Space Settings → Secrets → add `GOOGLE_API_KEY` with your key, then rebuild the Space."
        )
    else:
        try:
            resp = await _call_gemini_generate(user_text)
            reply = getattr(resp, "text", None) or str(resp)
        except RuntimeError as e:
            reply = f"[Runtime Error] {e}"
        except Exception as e:
            reply = f"[Error calling Gemini API] {e}"

    # Update the progress message with final reply
    try:
        await progress.update(content=reply)
    except Exception as e:
        await cl.Message(content=reply).send()

    # Save assistant reply to history
    history.append({"role": "assistant", "content": reply})
    cl.user_session.set("message_history", history)

if __name__ == "__main__":
    logging.info("Starting the application...")