from __future__ import unicode_literals

import contextlib

from auditlog.compat import is_authenticated
from auditlog.context import set_actor


@contextlib.contextmanager
def nullcontext():
    """Equivalent to contextlib.nullcontext(None) from Python 3.7."""
    yield


class AuditlogMiddleware(object):
    """
    Middleware to couple the request's user to log items. This is accomplished by currying the signal receiver with the
    user from the request (or None if the user is not authenticated).
    """

    def __init__(self, get_response=None):
        self.get_response = get_response

    def __call__(self, request):

        if request.META.get('HTTP_X_FORWARDED_FOR'):
            # In case of proxy, set 'original' address
            remote_addr = request.META.get('HTTP_X_FORWARDED_FOR').split(',')[0]
        else:
            remote_addr = request.META.get('REMOTE_ADDR')

        if hasattr(request, 'user') and is_authenticated(request.user):
            context = set_actor(actor=request.user, remote_addr=remote_addr)
        else:
            context = nullcontext()

        with context:
            return self.get_response(request)