"""

NL-specific Form helpers

"""

import re

from django.forms import ValidationError

from django.forms.fields import Field, Select, EMPTY_VALUES

from django.utils.translation import ugettext_lazy as _

from django.utils.encoding import smart_unicode

pc_re = re.compile('^\d{4}[A-Z]{2}$')

sofi_re = re.compile('^\d{9}$')

numeric_re = re.compile('^\d+$')

class NLZipCodeField(Field):

    """

    A Dutch postal code field.

    """

    default_error_messages = {

        'invalid': _('Enter a valid postal code'),

    }

    def clean(self, value):

        super(NLZipCodeField, self).clean(value)

        if value in EMPTY_VALUES:

            return u''

        value = value.strip().upper().replace(' ', '')

        if not pc_re.search(value):

            raise ValidationError(self.error_messages['invalid'])

        if int(value[:4]) < 1000:

            raise ValidationError(self.error_messages['invalid'])

        return u'%s %s' % (value[:4], value[4:])

class NLProvinceSelect(Select):

    """

    A Select widget that uses a list of provinces of the Netherlands as its

    choices.

    """

    def __init__(self, attrs=None):

        from nl_provinces import PROVINCE_CHOICES

        super(NLProvinceSelect, self).__init__(attrs, choices=PROVINCE_CHOICES)

class NLPhoneNumberField(Field):

    """

    A Dutch telephone number field.

    """

    default_error_messages = {

        'invalid': _('Enter a valid phone number'),

    }

    def clean(self, value):

        super(NLPhoneNumberField, self).clean(value)

        if value in EMPTY_VALUES:

            return u''

        phone_nr = re.sub('[\-\s\(\)]', '', smart_unicode(value))

        if len(phone_nr) == 10 and numeric_re.search(phone_nr):

            return value

        if phone_nr[:3] == '+31' and len(phone_nr) == 12 and \

           numeric_re.search(phone_nr[3:]):

            return value

        raise ValidationError(self.error_messages['invalid'])

class NLSoFiNumberField(Field):

    """

    A Dutch social security number (SoFi/BSN) field.

    http://nl.wikipedia.org/wiki/Sofinummer

    """

    default_error_messages = {

        'invalid': _('Enter a valid SoFi number'),

    }

    def clean(self, value):

        super(NLSoFiNumberField, self).clean(value)

        if value in EMPTY_VALUES:

            return u''

        if not sofi_re.search(value):

            raise ValidationError(self.error_messages['invalid'])

        if int(value) == 0:

            raise ValidationError(self.error_messages['invalid'])

        checksum = 0

        for i in range(9, 1, -1):

            checksum += int(value[9-i]) * i

        checksum -= int(value[-1])

        if checksum % 11 != 0:

            raise ValidationError(self.error_messages['invalid'])

        return value