from functools import wraps

from django.core.cache import cache
from django.http import JsonResponse
from django.contrib.auth import authenticate
from django.contrib.auth.models import User
from django.contrib.auth.backends import ModelBackend
from django.conf import settings

from rest_framework.exceptions import AuthenticationFailed

from mozilla_django_oidc.auth import OIDCAuthenticationBackend
from mozilla_django_oidc.contrib.drf import OIDCAuthentication


class CustomOIDCBackend(OIDCAuthenticationBackend):
    def get_username(self, claims):
        if 'preferred_username' in claims and not User.objects.filter(username=claims['preferred_username']).exists():
            return claims['preferred_username']
        return super().get_username(claims)

    def authenticate(self, request, **kwargs):
        """Hack to use the same auth as DRF"""
        back = OIDCAuthentication()
        try:
            u, tok = back.authenticate(request) or (None, None)
        except AuthenticationFailed:
            u = None
        return u
    
    def get_userinfo(self, access_token, id_token, payload):
        userinfo = cache.get(f'userinfo-{access_token}')
        if userinfo is None:
            userinfo = super().get_userinfo(access_token, id_token, payload)
            if userinfo:
                cache.set(f'userinfo-{access_token}', userinfo, timeout=settings.OIDC_CACHE_USERINFO)
        return userinfo

    def update_user(self, user, claims):  # TODO: update groups?
        return super().update_user(user, claims)

    def create_user(self, claims):  # TODO: add groups?
        return super().create_user(claims)


def login_required(func):
    @wraps(func)
    def wrapper(request, *args, **kwargs):
        if request.META.get("HTTP_AUTHORIZATION", "").startswith("Bearer"):
            if not hasattr(request, "user") or request.user.is_anonymous:
                user = authenticate(request=request)
                if not user:
                    return JsonResponse({"error": "Unauthorized"}, status=401)
                request.user = request._cached_user = user
        return func(request, *args, **kwargs)
    return wrapper