# This file is part of k4ever, a point-of-sale system
#   Contact............  <k4ever@lists.someserver.de>
#   Website............  http://k4ever.someserver.de/
#   Bug tracker........  http://k4ever.someserver.de/report
#
# Licensed under GNU Affero General Public License v3 or later

# FIXME: this needs to be reimplemented (not compatible with django 1.10+)
# https://docs.djangoproject.com/en/dev/ref/contrib/admin/#django.contrib.admin.ModelAdmin.list_filter
# http://stackoverflow.com/a/10644089

#from django.contrib.admin.filterspecs import FilterSpec, BooleanFieldFilterSpec
#
#class IsNegativeFilterSpec(FilterSpec):
#	""" Custom filter to display only users with negative balance """
#	def __init__(self, f, request, *args, **kwargs):
#		super(IsNegativeFilterSpec, self).__init__(f, request, *args, **kwargs)
#		self.lookup_kwarg = '%s__lt' % f.name
#		self.lookup_val = request.GET.get(self.lookup_kwarg, None) # Check if current request already has a filter
#
#	def title(self):
#		return 'Kontostand'
#
#	def choices(self, cl):
#		yield {
#				'selected': self.lookup_val == None,
#				'query_string': "?",
#				'display': 'Alle'}
#		yield {
#				'selected': self.lookup_val == '0',
#				'query_string': cl.get_query_string(
#								{self.lookup_kwarg: 0},
#								['balance__isnull']),
#				'display': 'Nur Negative'}
#
#FilterSpec.filter_specs.insert(0, (lambda f: getattr(f, 'has_negative_filter', False), IsNegativeFilterSpec))