bot.py

import logging
from telegram import Update
from telegram.ext import Application, MessageHandler, filters, ContextTypes

# --- Configuration ---
# 1. Replace with your actual bot token
BOT_TOKEN = "8103639461:AAF_F1lLwqKWUWUIuR-erBVzsODz1W37DYM" 

# 2. Specify the base URL for the API server.
#    - For the official Telegram API: "https://api.telegram.org/"
#    - For a locally hosted API server: e.g., "http://localhost:8081/"
BASE_API_URL = "https://hu-c3kd.onrender.com/see/bot" # We use the official URL here as an explicit example

# Set up logging for better error visibility
logging.basicConfig(
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
    level=logging.INFO
)
logger = logging.getLogger(__name__)


# --- Handler Functions ---

async def echo(update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
    """
    Echoes the user's message back to them.
    This function is an asynchronous coroutine (`async def`).
    """
    user_text = update.message.text
    logger.info(f"Received message from {update.message.from_user.username}: {user_text}")
    
    # Send the received text back to the same chat
    await update.message.reply_text(user_text)
    

async def start(update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
    """Sends a greeting when the command /start is issued."""
    await update.message.reply_text("Hello! I am an echo bot. Send me any message and I will repeat it back to you.")


# --- Main Application Setup ---

def main() -> None:
    """Start the bot."""
    
    # 1. Build the Application using the builder pattern
    application = (
        Application.builder()
        .token(BOT_TOKEN)
        # 2. Explicitly set the base_url for the API server
        #    Note: PTB adds 'bot<token>/' automatically, so only the root is needed.
        .base_url(BASE_API_URL) 
        .build()
    )

    # 3. Add Handlers to the Application
    # A MessageHandler filters for regular messages (not commands) and passes them to the echo function.
    # filters.TEXT & ~filters.COMMAND ensures only text messages that are NOT commands are processed.
    application.add_handler(MessageHandler(filters.TEXT & ~filters.COMMAND, echo))

    # A CommandHandler filters for /start command
    from telegram.ext import CommandHandler
    application.add_handler(CommandHandler("start", start))


    # 4. Start the Bot: The bot runs indefinitely until interrupted (e.g., Ctrl+C)
    logger.info("Bot started successfully. Polling for updates...")
    application.run_polling(allowed_updates=Update.ALL_TYPES)


if __name__ == '__main__':
    main()