from django.utils.module_loading import import_string
from rest_framework import generics, status
from rest_framework.request import Request
from rest_framework.response import Response
from rest_framework.serializers import Serializer

from .authentication import AUTH_HEADER_TYPES
from .exceptions import InvalidToken, TokenError
from .settings import api_settings


class TokenViewBase(generics.GenericAPIView):
    permission_classes = ()
    authentication_classes = ()

    serializer_class = None
    _serializer_class = ""

    www_authenticate_realm = "api"

    def get_serializer_class(self) -> Serializer:
        """
        If serializer_class is set, use it directly. Otherwise get the class from settings.
        """

        if self.serializer_class:
            return self.serializer_class
        try:
            return import_string(self._serializer_class)
        except ImportError:
            msg = f"Could not import serializer '{self._serializer_class}'"
            raise ImportError(msg)

    def get_authenticate_header(self, request: Request) -> str:
        return '{} realm="{}"'.format(
            AUTH_HEADER_TYPES[0],
            self.www_authenticate_realm,
        )

    def post(self, request: Request, *args, **kwargs) -> Response:
        serializer = self.get_serializer(data=request.data)

        try:
            serializer.is_valid(raise_exception=True)
        except TokenError as e:
            raise InvalidToken(e.args[0])

        return Response(serializer.validated_data, status=status.HTTP_200_OK)


class TokenObtainPairView(TokenViewBase):
    """
    Takes a set of user credentials and returns an access and refresh JSON web
    token pair to prove the authentication of those credentials.
    """

    _serializer_class = api_settings.TOKEN_OBTAIN_SERIALIZER


token_obtain_pair = TokenObtainPairView.as_view()


class TokenRefreshView(TokenViewBase):
    """
    Takes a refresh type JSON web token and returns an access type JSON web
    token if the refresh token is valid.
    """

    _serializer_class = api_settings.TOKEN_REFRESH_SERIALIZER


token_refresh = TokenRefreshView.as_view()


class TokenObtainSlidingView(TokenViewBase):
    """
    Takes a set of user credentials and returns a sliding JSON web token to
    prove the authentication of those credentials.
    """

    _serializer_class = api_settings.SLIDING_TOKEN_OBTAIN_SERIALIZER


token_obtain_sliding = TokenObtainSlidingView.as_view()


class TokenRefreshSlidingView(TokenViewBase):
    """
    Takes a sliding JSON web token and returns a new, refreshed version if the
    token's refresh period has not expired.
    """

    _serializer_class = api_settings.SLIDING_TOKEN_REFRESH_SERIALIZER


token_refresh_sliding = TokenRefreshSlidingView.as_view()


class TokenVerifyView(TokenViewBase):
    """
    Takes a token and indicates if it is valid.  This view provides no
    information about a token's fitness for a particular use.
    """

    _serializer_class = api_settings.TOKEN_VERIFY_SERIALIZER


token_verify = TokenVerifyView.as_view()


class TokenBlacklistView(TokenViewBase):
    """
    Takes a token and blacklists it. Must be used with the
    `rest_framework_simplejwt.token_blacklist` app installed.
    """

    _serializer_class = api_settings.TOKEN_BLACKLIST_SERIALIZER


token_blacklist = TokenBlacklistView.as_view()