from os import getenv
from enum import Enum
import logging

from telegram import Update, Bot
from telegram.ext import ApplicationBuilder, CommandHandler, ChatJoinRequestHandler, ConversationHandler, MessageHandler
from telegram.ext import Updater, ContextTypes, filters

passphrase=r"I want to join the channel"

TOKEN = getenv('TELEGRAM_BOT_TOKEN')

logging.basicConfig(
        format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
        level=logging.INFO)

class States(Enum):
    WAITING_FOR_VERIFICATION = 1

async def start(update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
    await update.message.reply_text(f'I am the bot, type me something!')

# Processing user's join request
async def join_request(update: Update, context: ContextTypes.DEFAULT_TYPE):

    logging.info(f"Captured attempt of user to join the group.\n\tUser : {update.effective_user.id}\n\tGroup: {update.effective_chat.id}")

    # sending user a private message
    await context.bot.send_message(
        chat_id=update.effective_user.id,text=
        f"Dummy captcha. Just respond '{passphrase}' (without brackets) to this message"
    )

    # Store chat join request details in context for later use
    context.user_data['join_request_chat_id'] = update.effective_chat.id
    context.user_data['join_request_user_id'] = update.effective_user.id
    
    return States.WAITING_FOR_VERIFICATION

async def verify_user_response(update: Update, context: ContextTypes.DEFAULT_TYPE):
    logging.info(f"Verification state triggered")
    logging.info(f"Update details: {update}")
    logging.info(f"Context user data: {context.user_data}")

    user_response = update.message.text
    logging.info(f"Captured responce of user : {update.effective_user.id}\n\tResponce: {user_response}")
    
    if user_response == passphrase:
        # Approve join request using stored details
        await context.bot.approve_chat_join_request(
            chat_id=context.user_data['join_request_chat_id'], 
            user_id=context.user_data['join_request_user_id']
        )
        await update.message.reply_text("Verification successful! You'll be forwarded to group now.")
        logging.info(f"User passed the verification and added to group:\n\t {update.effective_user.id}")
        return ConversationHandler.END
    else:
        # Decline join request
        await context.bot.decline_chat_join_request(
            chat_id=context.user_data['join_request_chat_id'], 
            user_id=context.user_data['join_request_user_id']
        )
        await update.message.reply_text("Verification failed. You cannot join the group.")
        logging.info(f"User FAILED the verification and NOT added to group:\n\t {update.effective_user.id}")
        return ConversationHandler.END


if __name__ == '__main__':

    default_bot = Bot(TOKEN)

    logging.info("Succesfully retrieved token")

    app = ApplicationBuilder().bot(default_bot).build()
    
    logging.info("Succesfully created application")

    # Create a handler for private mesage to user

    conv_handler = ConversationHandler(
        entry_points=[ChatJoinRequestHandler(join_request)],
        states={
            States.WAITING_FOR_VERIFICATION: [
                # Only plain text, no edited messages, no commands in privat conversation
                MessageHandler( filters.TEXT & ~filters.COMMAND & ~filters.UpdateType.EDITED_MESSAGE, verify_user_response)
            ]
        },
        fallbacks=[]
    )

    # Commands    
    app.add_handler(CommandHandler("start", start))

    # Conversations
    app.add_handler(conv_handler)

    # Finally run!
    
    app.run_polling(allowed_updates=Update.ALL_TYPES)