app.py

import gradio as gr
import requests
import os
import time
from threading import Thread, Event

# Configuration
COLAB_URL = os.getenv("COLAB_URL", "https://7ab1-35-187-228-56.ngrok-free.app/chat")
TIMEOUT = 25
POLL_INTERVAL = 3  # Seconds between status checks

# Connection manager
class ConnectionManager:
    def __init__(self):
        self.active = False
        self.stop_event = Event()
        self.thread = Thread(target=self._monitor, daemon=True)
        self.thread.start()
    
    def _monitor(self):
        while not self.stop_event.is_set():
            try:
                response = requests.get(f"{COLAB_URL}/health", timeout=5)
                self.active = response.status_code == 200
            except:
                self.active = False
            time.sleep(POLL_INTERVAL)
    
    def stop(self):
        self.stop_event.set()

conn = ConnectionManager()

def respond(message, history):
    if not conn.active:
        return "🔴 Backend offline - keep Colab notebook running"
    
    try:
        response = requests.post(
            f"{COLAB_URL}/chat",
            json={"prompt": message},
            headers={"Content-Type": "application/json"},
            timeout=TIMEOUT
        )
        return response.json().get("response", "Empty response")
    except requests.exceptions.RequestException as e:
        return f"⚠️ Connection error: {str(e)}"

# Create interface
with gr.Blocks(title="Phi-3 Chatbot") as demo:
    gr.Markdown("## 💬 Phi-3-mini (Colab Backend)")
    
    status = gr.Textbox(
        value="🟢 Connected" if conn.active else "🔴 Connecting...",
        label="Status",
        interactive=False
    )
    
    # Manual status updates
    def update_status():
        return "🟢 Connected" if conn.active else "🔴 Backend offline"
    
    # Add dummy hidden component for polling
    dummy = gr.Textbox(visible=False)
    
    # Set up polling
    def poll_status():
        while True:
            time.sleep(POLL_INTERVAL)
            yield update_status()
    
    dummy.change(
        fn=poll_status,
        outputs=status,
        show_progress=False
    )
    
    chatbot = gr.Chatbot(height=350)
    msg = gr.Textbox(placeholder="Type message...")
    msg.submit(respond, [msg, chatbot], [msg, chatbot])

# Launch with cleanup
try:
    demo.launch(server_name="0.0.0.0", server_port=int(os.getenv("PORT", 7860)))
finally:
    conn.stop()