"""
This file is used by TeleBot.run_webhooks() &
AsyncTeleBot.run_webhooks() functions.

Flask/fastapi is required to run this script.
"""

# modules required for running this script
fastapi_installed = True

try:
    import fastapi
    from fastapi.responses import JSONResponse
    from fastapi.requests import Request
    import uvicorn
except ImportError:
    fastapi_installed = False


from telebot.types import Update


from typing import Optional




class SyncWebhookListener:
    def __init__(self, bot, 
                secret_token: str, host: Optional[str]="127.0.0.1", 
                port: Optional[int]=443,
                ssl_context: Optional[tuple]=None,
                url_path: Optional[str]=None,
                debug: Optional[bool]=False
                ) -> None:
        """
        Synchronous implementation of webhook listener
        for synchronous version of telebot.

        :param bot: TeleBot instance
        :param secret_token: Telegram secret token
        :param host: Webhook host
        :param port: Webhook port
        :param ssl_context: SSL context
        :param url_path: Webhook url path
        :param debug: Debug mode
        """
        self._check_dependencies()

        self.app = fastapi.FastAPI()
        self._secret_token = secret_token
        self._bot = bot
        self._port = port
        self._host = host
        self._ssl_context = ssl_context
        self._url_path = url_path
        self._debug = debug
        self._prepare_endpoint_urls()


    def _check_dependencies(self):
        if not fastapi_installed:
            raise ImportError('Fastapi or uvicorn is not installed. Please install it via pip.')
            
        import starlette
        if starlette.__version__ < '0.20.2':
            raise ImportError('Starlette version is too old. Please upgrade it: `pip3 install starlette -U`')
        return

    
    def _prepare_endpoint_urls(self):
        self.app.add_api_route(endpoint=self.process_update,path= self._url_path, methods=["POST"])


    def process_update(self, request: Request, update: dict):
        """
        Processes updates.
        """
        # header containsX-Telegram-Bot-Api-Secret-Token
        if request.headers.get('X-Telegram-Bot-Api-Secret-Token') != self._secret_token:
            # secret token didn't match
            return JSONResponse(status_code=403, content={"error": "Forbidden"})
        if request.headers.get('content-type') == 'application/json':
            self._bot.process_new_updates([Update.de_json(update)])
            return JSONResponse('', status_code=200)

        return JSONResponse(status_code=403, content={"error": "Forbidden"})


    def run_app(self):
        """
        Run app with the given parameters.
        """

        uvicorn.run(app=self.app,
            host=self._host,
            port=self._port,
            debug=self._debug,
            ssl_certfile=self._ssl_context[0],
            ssl_keyfile=self._ssl_context[1]
        )