main.py

import os
from telegram.ext import Updater, MessageHandler, Filters, CallbackQueryHandler
from telegram import InlineKeyboardButton, InlineKeyboardMarkup, Bot
from pytube import YouTube
from dotenv import load_dotenv
load_dotenv()

TOKEN = os.getenv('TOKEN')


class Bot:
    url = ""
    current_streams = []
    current_itag = ""

    def __init__(self, TOKEN):
        updater = Updater(TOKEN, use_context=True)

        updater.dispatcher.add_handler(MessageHandler(Filters.text, self.main_handler))
        updater.dispatcher.add_handler(CallbackQueryHandler(self.button))

        updater.start_polling()
        updater.idle()

    def send_video(self, path, update):
        update.callback_query.message.reply_video(video=open(path, 'rb'), supports_streaming=True)

    def download_stream(self):
        path_to_download = self.current_streams.get_by_itag(self.current_itag).download(output_path="downloads/")
        return path_to_download

    def get_download_keyboard(self):
        yt = YouTube(self.url)

        keyboard = []

        self.current_streams = yt.streams.filter(progressive=True).order_by('resolution')

        for stream in self.current_streams:
            mime_type = "{} {}".format("🎵" if "audio" in stream.mime_type else "📺", stream.mime_type)

            quality = stream.resolution if stream.resolution != None else stream.abr
            quality = quality if quality != None else "❔"

            description = "{} {}".format(quality, mime_type)

            data = "{} | {}".format(stream.itag, description)
            keyboard.append([InlineKeyboardButton(description, callback_data=data)])

        return keyboard

    def button(self, update, context):
        query = update.callback_query
        query.answer()

        itag, description = query.data.split("|")
        self.current_itag = itag

        query.edit_message_text(text="Selected option: {}".format(description))

        path = self.download_stream()
        self.send_video(path, update)

    def main_handler(self, update, context):
        if (update.message.text.lower()) == "help":
            response = 'Hello {}.\n\nThis bot is incredibly simple to use. Just send a link to the YouTube video you would like to download, and it will sent to you.\n\ne.g. just send "https://youtu.be/E9oKEJ1pXPw"'.format(update.message.from_user.first_name)
        else:
            try:
                self.url = url = update.message.text[3:]
                keyboard = self.get_download_keyboard()
                reply_markup = InlineKeyboardMarkup(keyboard)

                update.message.reply_text('Please choose an option:', reply_markup=reply_markup)
                response = "Your download will begin after you select an option."

            except:
                response = "You have not entered a valid YouTube URL. Type help for assistance."

        update.message.reply_text(response)


b = Bot(TOKEN)