from django.utils.encoding import force_str
from django.utils.translation import gettext_lazy as _
[docs]def ssn_check_digit(value):
"""Calculate Italian social security number check digit."""
ssn_even_chars = {
'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8,
'9': 9, 'A': 0, 'B': 1, 'C': 2, 'D': 3, 'E': 4, 'F': 5, 'G': 6, 'H': 7,
'I': 8, 'J': 9, 'K': 10, 'L': 11, 'M': 12, 'N': 13, 'O': 14, 'P': 15,
'Q': 16, 'R': 17, 'S': 18, 'T': 19, 'U': 20, 'V': 21, 'W': 22, 'X': 23,
'Y': 24, 'Z': 25
}
ssn_odd_chars = {
'0': 1, '1': 0, '2': 5, '3': 7, '4': 9, '5': 13, '6': 15, '7': 17, '8':
19, '9': 21, 'A': 1, 'B': 0, 'C': 5, 'D': 7, 'E': 9, 'F': 13, 'G': 15,
'H': 17, 'I': 19, 'J': 21, 'K': 2, 'L': 4, 'M': 18, 'N': 20, 'O': 11,
'P': 3, 'Q': 6, 'R': 8, 'S': 12, 'T': 14, 'U': 16, 'V': 10, 'W': 22,
'X': 25, 'Y': 24, 'Z': 23
}
# Chars from 'A' to 'Z'
ssn_check_digits = [chr(x) for x in range(65, 91)]
ssn = value.upper()
total = 0
for i in range(0, 15):
try:
if i % 2 == 0:
total += ssn_odd_chars[ssn[i]]
else:
total += ssn_even_chars[ssn[i]]
except KeyError:
msg = "Character '%(char)s' is not allowed." % {'char': ssn[i]}
raise ValueError(msg)
return ssn_check_digits[total % 26]
[docs]def ssn_validation(ssn_value):
"""
Validate Italian SSN for persons
``ValueError`` is raised if validation fails.
"""
check_digit = ssn_check_digit(ssn_value)
if ssn_value[15] != check_digit:
raise ValueError(_('Check digit does not match.'))
return ssn_value
[docs]def vat_number_validation(vat_number):
"""
Validate Italian VAT number. Used also for entities SSN validation.
``ValueError`` is raised if validation fails.
"""
vat_number = str(int(vat_number)).zfill(11)
check_digit = vat_number_check_digit(vat_number[0:10])
if vat_number[10] != check_digit:
raise ValueError(_('Check digit does not match.'))
return force_str(vat_number)
[docs]def vat_number_check_digit(vat_number):
"""Calculate Italian VAT number check digit."""
normalized_vat_number = force_str(vat_number).zfill(10)
total = 0
for i in range(0, 10, 2):
total += int(normalized_vat_number[i])
for i in range(1, 11, 2):
quotient, remainder = divmod(int(normalized_vat_number[i]) * 2, 10)
total += quotient + remainder
return force_str((10 - total % 10) % 10)