"""Middleware utilities."""

from typing import Callable

from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request
from starlette.types import Receive
from starlette.types import Scope
from starlette.types import Send


class BaseMiddleware(BaseHTTPMiddleware):
    """The base middleware, used as a foundation for other middleware."""

    async def __call__(self, scope: Scope, receive: Receive, send: Send):
        """When the middleware is called.

        Supresses no response errors if the connection was terminated.

        Args:
            scope (Scope): Scope of the request
            receive (Receive): Receive channel
            send (Send): Send channel
        """
        try:
            await super().__call__(scope, receive, send)
        except RuntimeError as exc:
            if str(exc) == 'No response returned.':
                request = Request(scope, receive=receive)
                if await request.is_disconnected():
                    return
            raise

    async def dispatch(self, request: Request, call_next: Callable):
        """Dispach function. Purposely raises a NotImplementedError.

        Args:
            request (Request): Request to process.
            call_next (Callable): Middleware function to call next.
        """
        raise NotImplementedError()