"""
peeringdb model / field validators
"""

import ipaddress

from django.conf import settings
from django.core.exceptions import ValidationError
from django.utils.translation import ugettext_lazy as _

from peeringdb_server.inet import network_is_pdb_valid


def validate_address_space(prefix):
    """
    validate an ipaddress according to peeringdb specs

    Arguments:
        - prefix: ipaddress.IPv4Network or an ipaddress.IPv6Network

    Raises:
        - ValidationError on failed validation
    """

    if isinstance(prefix, unicode):
        try:
            prefix = ipaddress.ip_network(prefix)
        except ValueError as exc:
            raise ValidationError(_("Invalid prefix: {}").format(prefix))

    if not network_is_pdb_valid(prefix):
        raise ValidationError(_("Address space invalid: {}").format(prefix))

    prefixlen_min = getattr(settings, "DATA_QUALITY_MIN_PREFIXLEN_V{}".format(prefix.version))
    prefixlen_max = getattr(settings, "DATA_QUALITY_MAX_PREFIXLEN_V{}".format(prefix.version))

    if prefix.prefixlen < prefixlen_min:
        raise ValidationError(
            _("Minimum allowed prefix length is {}").format(prefixlen_min))
    elif prefix.prefixlen > prefixlen_max:
        raise ValidationError(
            _("Maximum allowed prefix length is {}").format(prefixlen_max))

def validate_info_prefixes4(value):
    if value > settings.DATA_QUALITY_MAX_PREFIX_V4_LIMIT:
        raise ValidationError(
            _("Maximum value allowed {}").format(
                settings.DATA_QUALITY_MAX_PREFIX_V4_LIMIT))
    if value < 0:
        raise ValidationError(_("Negative value not allowed"))


def validate_info_prefixes6(value):
    if value > settings.DATA_QUALITY_MAX_PREFIX_V6_LIMIT:
        raise ValidationError(
            _("Maximum value allowed {}").format(
                settings.DATA_QUALITY_MAX_PREFIX_V6_LIMIT))

    if value < 0:
        raise ValidationError(_("Negative value not allowed"))