# -*- coding: utf-8 -*-
# Copyright (c) 2012-2013 by Pablo Martín <goinnn@gmail.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this programe.  If not, see <http://www.gnu.org/licenses/>.

from django import forms
from django.contrib.humanize.templatetags.humanize import apnumber
from django.template.defaultfilters import pluralize


class MultiSelectFormField(forms.MultipleChoiceField):
    widget = forms.CheckboxSelectMultiple

    def __init__(self, *args, **kwargs):
        self.max_choices = kwargs.pop('max_choices', 0)
        super(MultiSelectFormField, self).__init__(*args, **kwargs)

    def clean(self, value):
        if not value and self.required:
            raise forms.ValidationError(self.error_messages['required'])
        if value and self.max_choices and len(value) > self.max_choices:
            raise forms.ValidationError('You must select a maximum of %s choice%s.'
                                        % (apnumber(self.max_choices),
                                           pluralize(self.max_choices)))
        return value