from django.contrib.auth.backends import ModelBackend

from axes.exceptions import AxesBackendPermissionDenied, AxesBackendRequestParameterRequired
from axes.handlers.proxy import AxesProxyHandler
from axes.helpers import get_credentials, get_lockout_message
from axes.request import AxesHttpRequest


class AxesBackend(ModelBackend):
    """
    Authentication backend class that forbids login attempts for locked out users.

    Use this class as the first item of ``AUTHENTICATION_BACKENDS`` to
    prevent locked out users from being logged in by the Django authentication flow.

    **Note:** this backend does not log your user in and delegates login to the
    backends that are configured after it in the ``AUTHENTICATION_BACKENDS`` list.
    """

    def authenticate(self, request: AxesHttpRequest, username: str = None, password: str = None, **kwargs: dict):
        """
        Checks user lockout status and raise a PermissionDenied if user is not allowed to log in.

        This method interrupts the login flow and inserts  error message directly to the
        ``response_context`` attribute that is supplied as a keyword argument.

        :keyword response_context: kwarg that will be have its ``error`` attribute updated with context.
        :raises AxesBackendRequestParameterRequired: if request parameter is not passed.
        :raises AxesBackendPermissionDenied: if user is already locked out.
        """

        if request is None:
            raise AxesBackendRequestParameterRequired('AxesBackend requires a request as an argument to authenticate')

        credentials = get_credentials(username=username, password=password, **kwargs)

        if AxesProxyHandler.is_allowed(request, credentials):
            return

        # Locked out, don't try to authenticate, just update response_context and return.
        # Its a bit weird to pass a context and expect a response value but its nice to get a "why" back.

        error_msg = get_lockout_message()
        response_context = kwargs.get('response_context', {})
        response_context['error'] = error_msg

        # Raise an error that stops the authentication flows at django.contrib.auth.authenticate.
        # This error stops bubbling up at the authenticate call which catches backend PermissionDenied errors.
        # After this error is caught by authenticate it emits a signal indicating user login failed,
        # which is processed by axes.signals.log_user_login_failed which logs the attempt and raises
        # a second exception which bubbles up the middleware stack and produces a HTTP 403 Forbidden reply
        # in the axes.middleware.AxesMiddleware.process_exception middleware exception handler.

        raise AxesBackendPermissionDenied('AxesBackend detected that the given user is locked out')

from django.contrib.auth.backends import ModelBackend

from axes.exceptions import AxesBackendPermissionDenied, AxesBackendRequestParameterRequired
from axes.handlers.proxy import AxesProxyHandler
from axes.helpers import get_credentials, get_lockout_message
from axes.request import AxesHttpRequest


class AxesBackend(ModelBackend):
    """
    Authentication backend class that forbids login attempts for locked out users.

    Use this class as the first item of ``AUTHENTICATION_BACKENDS`` to
    prevent locked out users from being logged in by the Django authentication flow.

    **Note:** this backend does not log your user in and delegates login to the
    backends that are configured after it in the ``AUTHENTICATION_BACKENDS`` list.
    """

    def authenticate(self, request: AxesHttpRequest, username: str = None, password: str = None, **kwargs: dict):
        """
        Checks user lockout status and raise a PermissionDenied if user is not allowed to log in.

        This method interrupts the login flow and inserts  error message directly to the
        ``response_context`` attribute that is supplied as a keyword argument.

        :keyword response_context: kwarg that will be have its ``error`` attribute updated with context.
        :raises AxesBackendRequestParameterRequired: if request parameter is not passed.
        :raises AxesBackendPermissionDenied: if user is already locked out.
        """

        if request is None:
            raise AxesBackendRequestParameterRequired('AxesBackend requires a request as an argument to authenticate')

        credentials = get_credentials(username=username, password=password, **kwargs)

        if AxesProxyHandler.is_allowed(request, credentials):
            return

        # Locked out, don't try to authenticate, just update response_context and return.
        # Its a bit weird to pass a context and expect a response value but its nice to get a "why" back.

        error_msg = get_lockout_message()
        response_context = kwargs.get('response_context', {})
        response_context['error'] = error_msg

        # Raise an error that stops the authentication flows at django.contrib.auth.authenticate.
        # This error stops bubbling up at the authenticate call which catches backend PermissionDenied errors.
        # After this error is caught by authenticate it emits a signal indicating user login failed,
        # which is processed by axes.signals.log_user_login_failed which logs the attempt and raises
        # a second exception which bubbles up the middleware stack and produces a HTTP 403 Forbidden reply
        # in the axes.middleware.AxesMiddleware.process_exception middleware exception handler.

        raise AxesBackendPermissionDenied('AxesBackend detected that the given user is locked out')


class AxesModelBackend(AxesBackend):
    """
    Backwards compatibility class for version 4 to version 5 migration.
    """

Add deprecation shim for AxesModelBackend