"""
Kuwait-specific Form helpers
"""
import re
from datetime import date
from django.core.validators import EMPTY_VALUES
from django.forms import ValidationError
from django.forms.fields import Field,RegexField
from django.utils.translation import gettext
id_re = re.compile(r'^(?P<initial>\d{1})(?P<yy>\d\d)(?P<mm>\d\d)(?P<dd>\d\d)(?P<mid>\d{4})(?P<checksum>\d{1})')
class KWCivilIDNumberField(Field):
"""
Kuwaiti Civil ID numbers are 12 digits, second to seventh digits
represents the person's birthdate.
Checks the following rules to determine the validty of the number:
* The number consist of 12 digits.
* The birthdate of the person is a valid date.
* The calculated checksum equals to the last digit of the Civil ID.
"""
default_error_messages = {
'invalid': _('Enter a valid Kuwaiti Civil ID number'),
}
def has_valid_checksum(self, value):
weight = (2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2)
calculated_checksum = 0
for i in range(11):
calculated_checksum += int(value[i]) * weight[i]
remainder = calculated_checksum % 11
checkdigit = 11 - remainder
if checkdigit != int(value[11]):
return False
return True
def clean(self, value):
super(KWCivilIDNumberField, self).clean(value)
if value in EMPTY_VALUES:
return u''
if not re.match(r'^\d{12}$', value):
raise ValidationError(self.error_messages['invalid'])
match = re.match(id_re, value)
if not match:
raise ValidationError(self.error_messages['invalid'])
gd = match.groupdict()
try:
d = date(int(gd['yy']), int(gd['mm']), int(gd['dd']))
except ValueError:
raise ValidationError(self.error_messages['invalid'])
if not self.has_valid_checksum(value):
raise ValidationError(self.error_messages['invalid'])
return value
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