1import six
2
3from django.core.exceptions import ValidationError
4from django.utils.translation import ugettext_lazy as _
5from django.contrib.admin import FieldListFilter
6from django.contrib.admin.options import IncorrectLookupParameters
7
8from bitfield import Bit, BitHandler
9
10
11class BitFieldListFilter(FieldListFilter):
12    """
13    BitField list filter.
14    """
15
16    def __init__(self, field, request, params, model, model_admin, field_path):
17        self.lookup_kwarg = field_path
18        self.lookup_val = int(request.GET.get(self.lookup_kwarg, 0))
19        self.flags = field.flags
20        self.labels = field.labels
21        super(BitFieldListFilter, self).__init__(
22            field, request, params, model, model_admin, field_path)
23
24    def queryset(self, request, queryset):
25        filter_kwargs = dict(
26            (p, BitHandler(v, ()))
27            for p, v in six.iteritems(self.used_parameters)
28        )
29        if not filter_kwargs:
30            return queryset
31        try:
32            return queryset.filter(**filter_kwargs)
33        except ValidationError as e:
34            raise IncorrectLookupParameters(e)
35
36    def expected_parameters(self):
37        return [self.lookup_kwarg]
38
39    def choices(self, cl):
40        yield {
41            'selected': self.lookup_val == 0,
42            'query_string': cl.get_query_string({}, [self.lookup_kwarg]),
43            'display': _('All'),
44        }
45        for number, flag in enumerate(self.flags):
46            bit_mask = Bit(number).mask
47            yield {
48                'selected': self.lookup_val == bit_mask,
49                'query_string': cl.get_query_string({self.lookup_kwarg: bit_mask}),
50                'display': self.labels[number],
51            }
52