from django.contrib.auth.mixins import AccessMixin
from django.contrib.messages import error
from django.views.decorators.cache import never_cache
from django.contrib.auth.views import redirect_to_login

from core.models.profiles import AdminProfile
from core.exceptions.auth import InsufficientPermissionsException

class AdminMixin(AccessMixin):
    permissions = []

    @never_cache
    def dispatch(self, request, *args, **kwargs):
        if not request.user.is_authenticated:
            self.permission_denied_message = "You must be logged in to access this area."
        else:
            try:
                user_permissions = AdminProfile.objects.get(user=request.user).permissions
                for permission in self.permissions:
                    if not permission in user_permissions:
                        raise InsufficientPermissionsException(f"Missing permission: {permission}")
                return super().dispatch(request, *args, **kwargs)
            except AdminProfile.DoesNotExist:
                self.permission_denied_message = "You must be an administrator to access this area."
            except InsufficientPermissionsException:
                self.permission_denied_message = "You do not have the necessary permissions to access this page."

        return self.handle_no_permission()

    def handle_no_permission(self):
        if self.raise_exception:
            raise PermissionDenied(self.get_permission_denied_message())

        error(self.request, self.permission_denied_message)
        
        return redirect_to_login(self.request.get_full_path(), self.get_login_url(), self.get_redirect_field_name())