import secrets
from typing import Union

from flask import Flask, Blueprint, Response, request


class BasicAuth:
    def __init__(self, app: Union[Flask, Blueprint], username: str, password: str):
        self.app = app
        self.username = username
        self.password = password

        self.app.before_request(self._before_request)

    def _check_auth(self, username, password):
        return secrets.compare_digest(username, self.username) and secrets.compare_digest(password, self.password)

    def _authenticate(self):
        return Response(
            'Could not verify your access level for that URL.\n'
            'You have to login with proper credentials', 401,
            {'WWW-Authenticate': 'Basic realm="Login Required"'})

    def _before_request(self):
        auth = request.authorization
        if not auth or not self._check_auth(auth.username, auth.password):
            return self._authenticate()
        return