class IntegerField(Field):
    empty_strings_allowed = False
    default_error_messages = {
        'invalid': _("This value must be an integer."),
    }
    description = _("Integer")

    def get_prep_value(self, value):
        if value is None:
            return None
        return int(value)

    def get_prep_lookup(self, lookup_type, value):
        if (lookup_type == 'gte' or lookup_type == 'lt') \
           and isinstance(value, float):
                value = math.ceil(value)
        return super(IntegerField, self).get_prep_lookup(lookup_type, value)

    def get_internal_type(self):
        return "IntegerField"

    def to_python(self, value):
        if value is None:
            return value
        try:
            return int(value)
        except (TypeError, ValueError):
            raise exceptions.ValidationError(self.error_messages['invalid'])

    def formfield(self, **kwargs):
        defaults = {'form_class': forms.IntegerField}
        defaults.update(kwargs)
        return super(IntegerField, self).formfield(**defaults)

class BigIntegerField(IntegerField):
    empty_strings_allowed = False
    description = _("Big (8 byte) integer")
    MAX_BIGINT = 9223372036854775807
    def get_internal_type(self):
        return "BigIntegerField"

    def formfield(self, **kwargs):
        defaults = {'min_value': -BigIntegerField.MAX_BIGINT - 1,
                    'max_value': BigIntegerField.MAX_BIGINT}
        defaults.update(kwargs)
        return super(BigIntegerField, self).formfield(**defaults)

class IPAddressField(Field):
    empty_strings_allowed = False
    description = _("IP address")
    def __init__(self, *args, **kwargs):
        kwargs['max_length'] = 15
        Field.__init__(self, *args, **kwargs)

    def get_internal_type(self):
        return "IPAddressField"

    def formfield(self, **kwargs):
        defaults = {'form_class': forms.IPAddressField}
        defaults.update(kwargs)
        return super(IPAddressField, self).formfield(**defaults)

class NullBooleanField(Field):
    empty_strings_allowed = False
    default_error_messages = {
        'invalid': _("This value must be either None, True or False."),
    }
    description = _("Boolean (Either True, False or None)")