import logging
import json
import six

from django.core.exceptions import PermissionDenied
from django.utils.functional import SimpleLazyObject
from django.http import HttpResponse

from rest_framework import status

from dockerhub import utils

logger = logging.getLogger(__name__)


def get_user(request):
    if not hasattr(request, '_cached_user'):
        request._cached_user = utils.get_user(request)
    return request._cached_user


class AuthenticationMiddleware(object):
    def process_request(self, request):
        assert hasattr(request, 'session'), "The Hub authentication middleware requires session middleware to be installed. Edit your MIDDLEWARE_CLASSES setting to insert 'django.contrib.sessions.middleware.SessionMiddleware'."

        request.user = SimpleLazyObject(lambda: get_user(request))


class UserUUIDSessionMiddleware(object):
    def process_request(self, request):
        try:
            request.session['_user_uuid'] = request.user.uuid.hex
        except AttributeError:
            logger.info('User `{}` does not have a UUID'.format(request.user))
            pass


class DockerHubAPIExceptionMiddleware(object):
    def process_exception(self, request, exception):
        if request.META.get('PATH_INFO', '').startswith('/v2/'):
            response_data = {'error': True, 'detail': str(exception)}

            if isinstance(exception, PermissionDenied):
                # Swagger is under /v2, but doesn't deal with permission error well
                status_code = status.HTTP_401_UNAUTHORIZED
            else:
                status_code = status.HTTP_500_INTERNAL_SERVER_ERROR

            return HttpResponse(
                json.dumps(response_data),
                content_type="application/json",
                status=status_code
            )