# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Address objects for network connections.
"""


import os
from typing import Optional, Union
from warnings import warn

from zope.interface import implementer

import attr
from typing_extensions import Literal

from twisted.internet.interfaces import IAddress
from twisted.python.filepath import _asFilesystemBytes, _coerceToFilesystemEncoding
from twisted.python.runtime import platform


@implementer(IAddress)
@attr.s(hash=True, auto_attribs=True)
class IPv4Address:
    """
    An L{IPv4Address} represents the address of an IPv4 socket endpoint.

    @ivar type: A string describing the type of transport, either 'TCP' or
        'UDP'.

    @ivar host: A string containing a dotted-quad IPv4 address; for example,
        "127.0.0.1".
    @type host: C{str}

    @ivar port: An integer representing the port number.
    @type port: C{int}
    """

    type: Union[Literal["TCP"], Literal["UDP"]] = attr.ib(
        validator=attr.validators.in_(["TCP", "UDP"])
    )
    host: str
    port: int


@implementer(IAddress)
@attr.s(hash=True, auto_attribs=True)
class IPv6Address:
    """
    An L{IPv6Address} represents the address of an IPv6 socket endpoint.

    @ivar type: A string describing the type of transport, either 'TCP' or
        'UDP'.

    @ivar host: A string containing a colon-separated, hexadecimal formatted
        IPv6 address; for example, "::1".
    @type host: C{str}

    @ivar port: An integer representing the port number.
    @type port: C{int}

    @ivar flowInfo: the IPv6 flow label.  This can be used by QoS routers to
        identify flows of traffic; you may generally safely ignore it.
    @type flowInfo: L{int}

    @ivar scopeID: the IPv6 scope identifier - roughly analagous to what
        interface traffic destined for this address must be transmitted over.
    @type scopeID: L{int} or L{str}
    """

    type: Union[Literal["TCP"], Literal["UDP"]] = attr.ib(
        validator=attr.validators.in_(["TCP", "UDP"])
    )
    host: str
    port: int
    flowInfo: int = 0
    scopeID: Union[str, int] = 0


@implementer(IAddress)
class _ProcessAddress:
    """
    An L{interfaces.IAddress} provider for process transports.
    """


@attr.s(hash=True, auto_attribs=True)
@implementer(IAddress)
class HostnameAddress:
    """
    A L{HostnameAddress} represents the address of a L{HostnameEndpoint}.

    @ivar hostname: A hostname byte string; for example, b"example.com".
    @type hostname: L{bytes}

    @ivar port: An integer representing the port number.
    @type port: L{int}
    """

    hostname: bytes
    port: int


@attr.s(hash=False, repr=False, eq=False, auto_attribs=True)
@implementer(IAddress)
class UNIXAddress:
    """
    Object representing a UNIX socket endpoint.

    @ivar name: The filename associated with this socket.
    @type name: C{bytes}
    """

    name: Optional[bytes] = attr.ib(
        converter=attr.converters.optional(_asFilesystemBytes)
    )

    if getattr(os.path, "samefile", None) is not None:

        def __eq__(self, other: object) -> bool:
            """
            Overriding C{attrs} to ensure the os level samefile
            check is done if the name attributes do not match.
            """
            if not isinstance(other, self.__class__):
                return NotImplemented
            res = self.name == other.name
            if not res and self.name and other.name:
                try:
                    return os.path.samefile(self.name, other.name)
                except OSError:
                    pass
                except (TypeError, ValueError) as e:
                    # On Linux, abstract namespace UNIX sockets start with a
                    # \0, which os.path doesn't like.
                    if not platform.isLinux():
                        raise e
            return res

    else:

        def __eq__(self, other: object) -> bool:
            if isinstance(other, self.__class__):
                return self.name == other.name
            return NotImplemented

    def __repr__(self) -> str:
        name = self.name
        if name:
            name = _coerceToFilesystemEncoding("", self.name)
        return f"UNIXAddress({name!r})"

    def __hash__(self):
        if self.name is None:
            return hash((self.__class__, None))
        try:
            s1 = os.stat(self.name)
            return hash((s1.st_ino, s1.st_dev))
        except OSError:
            return hash(self.name)


# These are for buildFactory backwards compatibility due to
# stupidity-induced inconsistency.


class _ServerFactoryIPv4Address(IPv4Address):
    """Backwards compatibility hack. Just like IPv4Address in practice."""

    def __eq__(self, other: object) -> bool:
        if isinstance(other, tuple):
            warn(
                "IPv4Address.__getitem__ is deprecated.  " "Use attributes instead.",
                category=DeprecationWarning,
                stacklevel=2,
            )
            return (self.host, self.port) == other
        elif isinstance(other, IPv4Address):
            a = (self.type, self.host, self.port)
            b = (other.type, other.host, other.port)
            return a == b
        return NotImplemented