from django.contrib.admin.filters import RelatedFieldListFilter
from django.db.models.fields.related import ForeignObjectRel
from django.db.models.query_utils import Q
from django.utils.encoding import smart_str
from django.utils.translation import gettext as _


class RelatedFieldCheckBoxFilter(RelatedFieldListFilter):
    template = 'adminfilters/checkbox.html'

    def __init__(self, field, request, params, model, model_admin, field_path):
        self.model_admin = model_admin
        super().__init__(field, request, params, model, model_admin, field_path)
        self.lookup_val = request.GET.getlist(self.lookup_kwarg, [])

    def queryset(self, request, queryset):
        filters = Q()

        for val in self.lookup_val:
            filters.add(Q(**{self.lookup_kwarg: val}), Q.OR)

        if (self.lookup_val_isnull):
            filters.add(Q(**{self.lookup_kwarg_isnull: self.lookup_val_isnull}), Q.OR)

        return queryset.filter(filters)

    def choices(self, cl):
        try:
            from django.contrib.admin.views.main import EMPTY_CHANGELIST_VALUE
        except ImportError:
            EMPTY_CHANGELIST_VALUE = self.model_admin.get_empty_value_display()

        uncheck_all = []
        uncheck_all.append("{}={}".format(self.lookup_kwarg_isnull, 1))
        for i in self.lookup_choices:
            uncheck_all.append("{}={}".format(self.lookup_kwarg, i[0]))

        yield {
            'selected': not len(self.lookup_val) and not self.lookup_val_isnull,
            'query_string': cl.get_query_string({}, [self.lookup_kwarg, self.lookup_kwarg_isnull]),
            'display': _('All'),
            'check_to_remove': "&".join(uncheck_all)

        }
        yield {
            'selected': self.lookup_val_isnull,
            'query_string': cl.get_query_string({self.lookup_kwarg_isnull: 1},
                                                [self.lookup_kwarg, self.lookup_kwarg_isnull]),
            'display': _('None'),
            'uncheck_to_remove': "{}=1".format(self.lookup_kwarg_isnull)
        }
        for pk_val, val in self.lookup_choices:
            yield {
                'selected': smart_str(pk_val) in self.lookup_val,
                'query_string': cl.get_query_string(
                    {
                        self.lookup_kwarg: pk_val,
                    },
                    [self.lookup_kwarg_isnull]),
                'display': val,
                'uncheck_to_remove': "{}={}".format(self.lookup_kwarg, pk_val) if pk_val else ""
            }
        if ((isinstance(self.field, ForeignObjectRel) and self.field.field.null or
             hasattr(self.field, 'rel') and self.field.null)):
            yield {
                'selected': bool(self.lookup_val_isnull),
                'query_string': cl.get_query_string(
                    {
                        self.lookup_kwarg_isnull: 'True',
                    },
                    [self.lookup_kwarg]),
                'uncheck_to_remove': "{}=1".format(self.lookup_kwarg_isnull),
                'display': EMPTY_CHANGELIST_VALUE,
            }
