# Copyright 2007 Google Inc.
#  Licensed to PSF under a Contributor Agreement.

"""A fast, lightweight IPv4/IPv6 manipulation library in Python.

This library is used to create/poke/manipulate IPv4 and IPv6 addresses
and networks.

"""

from __future__ import unicode_literals


import itertools
import struct

__version__ = '1.0.22'

# Compatibility functions
_compat_int_types = (int,)
try:
    _compat_int_types = (int, long)
except NameError:
    pass
try:
    _compat_str = unicode
except NameError:
    _compat_str = str
    assert bytes != str
if b'\0'[0] == 0:  # Python 3 semantics
    def _compat_bytes_to_byte_vals(byt):
        return byt
else:
    def _compat_bytes_to_byte_vals(byt):
        return [struct.unpack(b'!B', b)[0] for b in byt]
try:
    _compat_int_from_byte_vals = int.from_bytes
except AttributeError:
    def _compat_int_from_byte_vals(bytvals, endianess):
        assert endianess == 'big'
        res = 0
        for bv in bytvals:
            assert isinstance(bv, _compat_int_types)
            res = (res << 8) + bv
        return res


def _compat_to_bytes(intval, length, endianess):
    assert isinstance(intval, _compat_int_types)
    assert endianess == 'big'
    if length == 4:
        if intval < 0 or intval >= 2 ** 32:
            raise struct.error("integer out of range for 'I' format code")
        return struct.pack(b'!I', intval)
    elif length == 16:
        if intval < 0 or intval >= 2 ** 128:
            raise struct.error("integer out of range for 'QQ' format code")
        return struct.pack(b'!QQ', intval >> 64, intval & 0xffffffffffffffff)
    else:
        raise NotImplementedError()


if hasattr(int, 'bit_length'):
    # Not int.bit_length , since that won't work in 2.7 where long exists
    def _compat_bit_length(i):
        return i.bit_length()
else:
    def _compat_bit_length(i):
        for res in itertools.count():
            if i >> res == 0:
                return res


def _compat_range(start, end, step=1):
    assert step > 0
    i = start
    while i < end:
        yield i
        i += step


class _TotalOrderingMixin(object):
    __slots__ = ()

    # Helper that derives the other comparison operations from
    # __lt__ and __eq__
    # We avoid functools.total_ordering because it doesn't handle
    # NotImplemented correctly yet (http://bugs.python.org/issue10042)
    def __eq__(self, other):
        raise NotImplementedError

    def __ne__(self, other):
        equal = self.__eq__(other)
        if equal is NotImplemented:
            return NotImplemented
        return not equal

    def __lt__(self, other):
        raise NotImplementedError

    def __le__(self, other):
        less = self.__lt__(other)
        if less is NotImplemented or not less:
            return self.__eq__(other)
        return less

    def __gt__(self, other):
        less = self.__lt__(other)
        if less is NotImplemented:
            return NotImplemented
        equal = self.__eq__(other)
        if equal is NotImplemented:
            return NotImplemented
        return not (less or equal)

    def __ge__(self, other):
        less = self.__lt__(other)
        if less is NotImplemented:
            return NotImplemented
        return not less


IPV4LENGTH = 32
IPV6LENGTH = 128


class AddressValueError(ValueError):
    """A Value Error related to the address."""


class NetmaskValueError(ValueError):
    """A Value Error related to the netmask."""


def ip_address(address):
    """Take an IP string/int and return an object of the correct type.

    Args:
        address: A string or integer, the IP address.  Either IPv4 or
          IPv6 addresses may be supplied; integers less than 2**32 will
          be considered to be IPv4 by default.

    Returns:
        An IPv4Address or IPv6Address object.

    Raises:
        ValueError: if the *address* passed isn't either a v4 or a v6
          address

    """
    try:
        return IPv4Address(address)
    except (AddressValueError, NetmaskValueError):
        pass

    try:
        return IPv6Address(address)
    except (AddressValueError, NetmaskValueError):
        pass

    if isinstance(address, bytes):
        raise AddressValueError(
            '%r does not appear to be an IPv4 or IPv6 address. '
            'Did you pass in a bytes (str in Python 2) instead of'
            ' a unicode object?' % address)

    raise ValueError('%r does not appear to be an IPv4 or IPv6 address' %
                     address)


def ip_network(address, strict=True):
    """Take an IP string/int and return an object of the correct type.

    Args:
        address: A string or integer, the IP network.  Either IPv4 or
          IPv6 networks may be supplied; integers less than 2**32 will
          be considered to be IPv4 by default.

    Returns:
        An IPv4Network or IPv6Network object.

    Raises:
        ValueError: if the string passed isn't either a v4 or a v6
          address. Or if the network has host bits set.

    """
    try:
        return IPv4Network(address, strict)
    except (AddressValueError, NetmaskValueError):
        pass

    try:
        return IPv6Network(address, strict)
    except (AddressValueError, NetmaskValueError):
        pass

    if isinstance(address, bytes):
        raise AddressValueError(
            '%r does not appear to be an IPv4 or IPv6 network. '
            'Did you pass in a bytes (str in Python 2) instead of'
            ' a unicode object?' % address)

    raise ValueError('%r does not appear to be an IPv4 or IPv6 network' %
                     address)


def ip_interface(address):
    """Take an IP string/int and return an object of the correct type.

    Args:
        address: A string or integer, the IP address.  Either IPv4 or
          IPv6 addresses may be supplied; integers less than 2**32 will
          be considered to be IPv4 by default.

    Returns:
        An IPv4Interface or IPv6Interface object.

    Raises:
        ValueError: if the string passed isn't either a v4 or a v6
          address.

    Notes:
        The IPv?Interface classes describe an Address on a particular
        Network, so they're basically a combination of both the Address
        and Network classes.

    """
    try:
        return IPv4Interface(address)
    except (AddressValueError, NetmaskValueError):
        pass

    try:
        return IPv6Interface(address)
    except (AddressValueError, NetmaskValueError):
        pass

    raise ValueError('%r does not appear to be an IPv4 or IPv6 interface' %
                     address)


def v4_int_to_packed(address):
    """Represent an address as 4 packed bytes in network (big-endian) order.

    Args:
        address: An integer representation of an IPv4 IP address.

    Returns:
        The integer address packed as 4 bytes in network (big-endian) order.

    Raises:
        ValueError: If the integer is negative or too large to be an
          IPv4 IP address.

    """
    try:
        return _compat_to_bytes(address, 4, 'big')
    except (struct.error, OverflowError):
        raise ValueError("Address negative or too large for IPv4")


def v6_int_to_packed(address):
    """Represent an address as 16 packed bytes in network (big-endian) order.

    Args:
        address: An integer representation of an IPv6 IP address.

    Returns:
        The integer address packed as 16 bytes in network (big-endian) order.

    """
    try:
        return _compat_to_bytes(address, 16, 'big')
    except (struct.error, OverflowError):
        raise ValueError("Address negative or too large for IPv6")


def _split_optional_netmask(address):
    """Helper to split the netmask and raise AddressValueError if needed"""
    addr = _compat_str(address).split('/')
    if len(addr) > 2:
        raise AddressValueError("Only one '/' permitted in %r" % address)
    return addr


def _find_address_range(addresses):
    """Find a sequence of sorted deduplicated IPv#Address.

    Args:
        addresses: a list of IPv#Address objects.

    Yields:
        A tuple containing the first and last IP addresses in the sequence.

    """
    it = iter(addresses)
    first = last = next(it)
    for ip in it:
        if ip._ip != last._ip + 1:
            yield first, last
            first = ip
        last = ip
    yield first, last


def _count_righthand_zero_bits(number, bits):
    """Count the number of zero bits on the right hand side.

    Args:
        number: an integer.
        bits: maximum number of bits to count.

    Returns:
        The number of zero bits on the right hand side of the number.

    """
    if number == 0:
        return bits
    return min(bits, _compat_bit_length(~number & (number - 1)))


def summarize_address_range(first, last):
    """Summarize a network range given the first and last IP addresses.

    Example:
        >>> list(summarize_address_range(IPv4Address('192.0.2.0'),
        ...                              IPv4Address('192.0.2.130')))
        ...                                #doctest: +NORMALIZE_WHITESPACE
        [IPv4Network('192.0.2.0/25'), IPv4Network('192.0.2.128/31'),
         IPv4Network('192.0.2.130/32')]

    Args:
        first: the first IPv4Address or IPv6Address in the range.
        last: the last IPv4Address or IPv6Address in the range.

    Returns:
        An iterator of the summarized IPv(4|6) network objects.

    Raise:
        TypeError:
            If the first and last objects are not IP addresses.
            If the first and last objects are not the same version.
        ValueError:
            If the last object is not greater than the first.
            If the version of the first address is not 4 or 6.