"""
Chile specific form helpers.
"""
from django.core.validators import EMPTY_VALUES
from django.forms import ValidationError
from django.forms.fields import RegexField,Select
from django.utils.translation import ugettext_lazy
from django.utils.encoding import smart_unicode
class CLRegionSelect(Select):
"""
A Select widget that uses a list of Chilean Regions (Regiones)
as its choices.
"""
def __init__(self, attrs=None):
from cl_regions import REGION_CHOICES
super(CLRegionSelect, self).__init__(attrs, choices=REGION_CHOICES)
class CLRutField(RegexField):
"""
Chilean "Rol Unico Tributario" (RUT) field. This is the Chilean national
identification number.
Samples for testing are available from
https://palena.sii.cl/cvc/dte/ee_empresas_emisoras.html
"""
default_error_messages = {
'invalid': _('Enter a valid Chilean RUT.'),
'strict': _('Enter a valid Chilean RUT. The format is XX.XXX.XXX-X.'),
'checksum': _('The Chilean RUT is not valid.'),
}
def __init__(self, *args, **kwargs):
if 'strict' in kwargs:
del kwargs['strict']
super(CLRutField, self).__init__(r'^(\d{1,2}\.)?\d{3}\.\d{3}-[\dkK]$',
error_message=self.default_error_messages['strict'], *args, **kwargs)
else:
# In non-strict mode, accept RUTs that validate but do not exist in
# the real world.
super(CLRutField, self).__init__(r'^[\d\.]{1,11}-?[\dkK]$', *args, **kwargs)
def clean(self, value):
"""
Check and clean the Chilean RUT.
"""
super(CLRutField, self).clean(value)
if value in EMPTY_VALUES:
return u''
rut, verificador = self._canonify(value)
if self._algorithm(rut) == verificador:
return self._format(rut, verificador)
else:
raise ValidationError(self.error_messages['checksum'])
def _algorithm(self, rut):
"""
Takes RUT in pure canonical form, calculates the verifier digit.
"""
suma = 0
multi = 2
for r in rut[::-1]:
suma += int(r) * multi
multi += 1
if multi == 8:
multi = 2
return u'0123456789K0'[11 - suma % 11]
def _canonify(self, rut):
"""
Turns the RUT into one normalized format. Returns a (rut, verifier)
tuple.
"""
rut = smart_unicode(rut).replace(' ', '').replace('.', '').replace('-', '')
return rut[:-1], rut[-1]
def _format(self, code, verifier=None):
"""
Formats the RUT from canonical form to the common string representation.
If verifier=None, then the last digit in 'code' is the verifier.
"""
if verifier is None:
verifier = code[-1]
code = code[:-1]
while len(code) > 3 and '.' not in code[:3]:
pos = code.find('.')
if pos == -1:
new_dot = -3
else:
new_dot = pos - 3
code = code[:new_dot] + '.' + code[new_dot:]
return u'%s-%s' % (code, verifier)
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