import json
import base64

from django.http import JsonResponse, HttpResponse
from django.conf import settings
from django.utils.translation import ugettext_lazy as _
from django.contrib.auth import authenticate

from django_namespace_perms.util import has_perms
from ratelimit.decorators import ratelimit, is_ratelimited

from peeringdb_server import ixf
from peeringdb_server.models import IXLan

RATELIMITS = settings.RATELIMITS

def enable_basic_auth(fn):
    """
    a simple decorator to enable basic auth for a specific view
    """
    def wrapped(request, *args, **kwargs):
        if 'HTTP_AUTHORIZATION' in request.META:
            auth = request.META['HTTP_AUTHORIZATION'].split()
            if len(auth) == 2:
                if auth[0].lower() == "basic":
                    username, password = base64.b64decode(auth[1]).split(':', 1)
                    request.user = authenticate(username=username, password=password)
                    if not request.user:
                        return JsonResponse({"non_field_errors":["Invalid credentials"]}, status=401)
        return fn(request, *args, **kwargs)
    return wrapped


@ratelimit(key="ip", rate=RATELIMITS["view_import_ixlan_ixf_preview"])
@enable_basic_auth
def view_import_ixlan_ixf_preview(request, ixlan_id):

    # check if request was blocked by rate limiting
    was_limited = getattr(request, "limited", False)
    if was_limited:
        return JsonResponse({
            "non_field_errors": [
                _("Please wait a bit before requesting " \
                  "another ixf import preview.")
            ]
        }, status=400)

    try:
        ixlan = IXLan.objects.get(id=ixlan_id)
    except IXLan.DoesNotExist:
        return JsonResponse({
            "non_field_errors": [_("Ixlan not found")]
        }, status=404)

    if not has_perms(request.user, ixlan, "update"):
        return JsonResponse({
            "non_field_errors": [_("Permission denied")]
        }, status=403)

    importer = ixf.Importer()
    importer.update(ixlan, save=False)

    return HttpResponse(
        json.dumps(importer.log, indent=2), content_type="application/json")