# 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 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
        show = _coerceToFilesystemEncoding("", name) if name is not None else None
        return f"UNIXAddress({show!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