import os
import re
import base64
import hashlib
import functools
import warnings
from os.path import isabs, abspath

from zope.interface import Interface, Attribute, implementer

from twisted.internet import defer
from twisted.python import log

from txtorcon.util import find_keywords, version_at_least
from txtorcon.util import _is_non_public_numeric_address
from txtorcon.util import available_tcp_port

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization


class HiddenServiceClientAuth:
    """
    Encapsulates a single client-authorization, as parsed from a
    HiddenServiceDir's "client_keys" file if you have stealth or basic
    authentication turned on.

    :param name: the name you gave it in the HiddenServiceAuthorizeClient line
    :param cookie: random password
    :param key: RSA private key, or None if this was basic auth
    """

    def __init__(self, name, cookie, key=None):
        self.name = name
        self.cookie = cookie
        self.key = _parse_rsa_blob(key) if key else None


class IOnionService(Interface):
    """
    Encapsulates a single, ephemeral onion service.

    If this instance happens to be a filesystem-based service (instead
    of ephemeral), it shall implement IFilesystemOnionService as well
    (which is a subclass of this).

    If this object happens to represent an authenticated service, it
    shall implement IAuthenticatedOnionClients ONLY (not this
    interface too; IAuthenticatedOnionClients returns *lists* of
    IOnionClient instances which are a subclass of
    IOnionService; see :class:`txtorcon.IAuthenticatedOnionClients`).

    For non-authenticated services, there will be one of these per
    directory (i.e. HiddenServiceDir) if using non-ephemeral services,
    or one per ADD_ONION for ephemeral hidden services.

    For authenticated services, there is an instance implementing this
    interface for each "client" of the authenticated service. In the
    "basic" case, the .onion URI happens to be the same for each one
    (with a different authethentication token) whereas for a "stealth"
    sevice the .onion URI is different.
    """
    hostname = Attribute("hostname, including .onion")  # XXX *with* .onion? or not?
    private_key = Attribute("Private key blob (bytes)")
    ports = Attribute("list of str; the ports lines like 'public_port host:local_port'")


class IFilesystemOnionService(IOnionService):
    """
    Encapsulates a single filesystem-based service.

    Note this is a subclass of IOnionService; it just adds two
    attributes that ephemeral services lack: hidden_service_directory
    and group_readable.
    """
    hidden_service_directory = Attribute('The directory where private data is kept')
    group_readable = Attribute("set HiddenServiceGroupReadable if true")


class IAuthenticatedOnionClients(Interface):
    """
    This encapsulates both 'stealth' and 'basic' authenticated Onion
    services, whether ephemeral or not.

    Each client has an arbitrary (ASCII, no spaces) name. You may
    access the clients with `get_client`, which will all be
    :class:`txtorcon.IOnionClient` instances.
    """

    def get_permanent_id(self):
        """
        :return: the service's permanent id, in hex

        (For authenticated services, this is not the same as the
        .onion URI of any of the clients). The Permanent ID is the
        base32 encoding of the first 10 bytes of the SHA1 hash of the
        public-key of the service.
        """

    def client_names(self):
        """
        :return: list of str instances, one for each client
        """

    def get_client(self, name):
        """
        :return: object implementing IOnionClient for the named client
        """

    def add_client(self, name):
        """
        probably should return a Deferred?
        """

    def del_client(self, name):
        """
        probably should return a Deferred?
        """


class IOnionClient(IOnionService):
    """
    A single client from a 'parent' IAuthenticatedOnionClients. We do
    this because hidden services can have different URLs and/or
    auth_tokens on a per-client basis. So, the only way to access
    *anything* from an authenticated onion service is to list the
    cleints -- which gives you one IOnionClient per client.

    Note that this inherits from :class:`txtorcon.IOnionService` and
    adds only those attributes required for authentication. For
    'stealth' authentication, the hostnames of each client will be
    unique; for 'basic' authentication the hostname is the same. The
    auth_tokens are always unique -- these are given to clients to
    include using the Tor option `HidServAuth`
    """
    auth_token = Attribute('Some secret bytes')
    name = Attribute('str')  # XXX required? probably.
    parent = Attribute('the IAuthenticatedOnionClients instance who owns me')
    # from the IOnionService base interface, inherits:
    #    hostname
    #    private_key
    #    ports


def _canonical_hsdir(hsdir):
    """
    Internal helper.

    :return: the absolute path for 'hsdir' (and issue a warning)
        issuing a warning) if it was relative. Otherwise, returns the path
        unmodified.
    """
    if not isabs(hsdir):
        abs_hsdir = abspath(hsdir)
        warnings.warn(
            "Onions service directory ({}) is relative and has"
            " been resolved to '{}'".format(hsdir, abs_hsdir)
        )
        hsdir = abs_hsdir
    return hsdir


@implementer(IOnionService)
@implementer(IFilesystemOnionService)
class FilesystemOnionService(object):
    """
    An Onion service whose keys are stored on disk.
    """

    @staticmethod
    @defer.inlineCallbacks
    def create(reactor, config, hsdir, ports,
               version=3,
               group_readable=False,
               progress=None,
               await_all_uploads=None):
        """
        returns a new FilesystemOnionService after adding it to the
        provided config and ensuring at least one of its descriptors
        is uploaded.

        :param config: a :class:`txtorcon.TorConfig` instance

        :param ports: a list of ports to make available; any of these
            can be 2-tuples of (remote, local) if you want to expose a
            particular port locally (otherwise, an available one is
            chosen)

        :param hsdir: the directory in which to store private keys

        :param version: 2 or 3, which kind of service to create

        :param group_readable: if True, the Tor option
            `HiddenServiceDirGroupReadable` is set to 1 for this service

        :param progress: a callable taking (percent, tag, description)
            that is called periodically to report progress.

        :param await_all_uploads: if True, the Deferred only fires
            after ALL descriptor uploads have completed (otherwise, it
            fires when at least one has completed).

        See also :meth:`txtorcon.Tor.create_onion_service` (which
        ultimately calls this).
        """

        # if hsdir is relative, it's "least surprising" (IMO) to make
        # it into a absolute path here -- otherwise, it's relative to
        # whatever Tor's cwd is.
        hsdir = _canonical_hsdir(hsdir)
        processed_ports = yield _validate_ports(reactor, ports)

        fhs = FilesystemOnionService(config, hsdir, processed_ports, version=version, group_readable=group_readable)
        config.HiddenServices.append(fhs)
        # we .save() down below, after setting HS_DESC listener

        # XXX I *hate* this version checking crap. Can we discover a
        # different way if this Tor supports proper HS_DESC stuff? I
        # think part of the problem here is that "some" Tors have
        # HS_DESC event, but it's not .. sufficient?
        uploaded = [None]
        if not version_at_least(config.tor_protocol.version, 0, 2, 7, 2):
            if progress:
                progress(
                    102, "wait_desctiptor",
                    "Adding an onion service to Tor requires at least version"
                )
                progress(
                    103, "wait_desctiptor",
                    "0.2.7.2 so that HS_DESC events work properly and we can"
                )
                progress(
                    104, "wait_desctiptor",
                    "detect our desctiptor being uploaded."
                )
                progress(
                    105, "wait_desctiptor",
                    "Your version is '{}'".format(config.tor_protocol.version),
                )
                progress(
                    106, "wait_desctiptor",
                    "So, we'll just declare it done right now..."
                )
                uploaded[0] = defer.succeed(None)
        else:
            # XXX actually, there's some versions of Tor when v3
            # filesystem services could be added but they didn't send
            # HS_DESC updates -- did any of these actually get
            # released?!
            uploaded[0] = _await_descriptor_upload(config.tor_protocol, fhs, progress, await_all_uploads)

        yield config.save()
        yield uploaded[0]
        return fhs

    def __init__(self, config, thedir, ports, version=3, group_readable=0):
        """
        Do not instantiate directly; use
        :func:`txtorcon.onion.FilesystemOnionService.create`
        """
        self._config = config
        self._dir = os.path.realpath(thedir)

        _validate_ports_low_level(ports)
        from .torconfig import _ListWrapper
        self._ports = _ListWrapper(
            ports,
            functools.partial(config.mark_unsaved, 'HiddenServices'),
        )
        self._version = version
        self._group_readable = group_readable
        self._hostname = None
        self._private_key = None

    @property
    def hostname(self):
        if self._hostname is None:
            try:
                with open(os.path.join(self._dir, 'hostname'), 'r') as f:
                    self._hostname = f.read().strip()
            except IOError:
                # not clear under what circumstances this happens
                # (i.e. we can create a new onion, but somehow not
                # read the hostname file) but ... safety?
                self._hostname = None
        return self._hostname

    @property
    def private_key(self):
        # XXX there's also a file called 'hs_ed25519_public_key' but I
        # think we can just ignore that? .. or do we need a v3-only
        # accessor for .public_key() as well?
        if self._private_key is None:
            if self.version == 2:
                try:
                    with open(os.path.join(self._dir, 'private_key'), 'r') as f:
                        self._private_key = f.read().strip()
                except IOError:
                    # not clear under what circumstances this happens
                    # (i.e. we can create a new onion, but somehow not
                    # read the private_key file) but ... safety?
                    self._private_key = None
            elif self.version == 3:
                # XXX see tor bug #20699 -- would be Really Nice to
                # not have to deal with binary data here (well, more
                # for ADD_ONION, but still)
                try:
                    with open(os.path.join(self._dir, 'hs_ed25519_secret_key'), 'rb') as f:
                        self._private_key = f.read().strip()
                except IOError:
                    # not clear under what circumstances this happens
                    # (i.e. we can create a new onion, but somehow not
                    # read the private key file) but ... safety?
                    self._private_key = None
            else:
                raise RuntimeError(
                    "Don't know how to load private_key for version={} "
                    "Onion service".format(self.version)
                )
        return self._private_key

    @property
    def ports(self):
        return self._ports

    @ports.setter
    def ports(self, ports):
        # XXX FIXME need to update Tor's notion of config and/or
        # reject this request after we *have* updated Tor..."or
        # something"
        from .torconfig import _ListWrapper
        self._ports = _ListWrapper(
            ports,
            functools.partial(self._config.mark_unsaved, 'HiddenServices'),
        )
        self._config.mark_unsaved('HiddenServices')

    @property
    def directory(self):
        return self._dir

    @directory.setter
    def directory(self, d):
        self._dir = d
        self._config.mark_unsaved('HiddenServices')

    @property
    def dir(self):
        # deprecated
        return self.directory

    @dir.setter
    def dir(self, d):
        # deprecated
        self.directory = d

    @property
    def group_readable(self):
        return self._group_readable

    @property
    def version(self):
        return self._version

    @version.setter
    def version(self, v):
        self._version = v
        self._config.mark_unsaved('HiddenServices')

    def config_attributes(self):
        """
        Helper method used by TorConfig when generating a torrc file and
        SETCONF commands
        """

        rtn = [('HiddenServiceDir', str(self._dir))]
        if self._config._supports['HiddenServiceDirGroupReadable'] \
           and self.group_readable:
            rtn.append(('HiddenServiceDirGroupReadable', str(1)))
        for x in self.ports:
            rtn.append(('HiddenServicePort', str(x)))
        if self.version:
            rtn.append(('HiddenServiceVersion', str(self.version)))
        return rtn


@defer.inlineCallbacks
def _await_descriptor_upload(tor_protocol, onion, progress, await_all_uploads):
    """
    Internal helper.

    :param tor_protocol: ITorControlProtocol instance

    :param onion: IOnionService instance

    :param progress: a progess callback, or None

    :returns: a Deferred that fires once we've detected at least one
        descriptor upload for the service (as detected by listening for
        HS_DESC events)
    """
    # For v3 services, Tor attempts to upload to 16 services; we'll
    # assume that for now but also cap it (we want to show some
    # progress for "attempting uploads" but we need to decide how
    # much) .. so we leave 50% of the "progress" for attempts, and the
    # other 50% for "are we done" (which is either "one thing
    # uploaded" or "all the things uploaded")
    attempted_uploads = set()
    confirmed_uploads = set()
    failed_uploads = set()
    uploaded = defer.Deferred()
    await_all = False if await_all_uploads is None else await_all_uploads

    def translate_progress(tag, description):
        if progress:
            done = len(confirmed_uploads) + len(failed_uploads)
            done_endpoint = float(len(attempted_uploads)) if await_all else 1.0
            done_pct = 0 if not attempted_uploads else float(done) / done_endpoint
            started_pct = float(min(16, len(attempted_uploads))) / 16.0
            try:
                progress(
                    (done_pct * 50.0) + (started_pct * 50.0),
                    tag,
                    description,
                )
            except Exception:
                log.err()

    def hostname_matches(hostname):
        if IAuthenticatedOnionClients.providedBy(onion):
            return hostname[:-6] == onion.get_permanent_id()
        else:
            # provides IOnionService
            return onion.hostname == hostname

    def hs_desc(evt):
        """
        From control-spec:
        "650" SP "HS_DESC" SP Action SP HSAddress SP AuthType SP HsDir
        [SP DescriptorID] [SP "REASON=" Reason] [SP "REPLICA=" Replica]
        """
        args = evt.split()
        subtype = args[0]
        if subtype == 'UPLOAD':
            if hostname_matches('{}.onion'.format(args[1])):
                attempted_uploads.add(args[3])
                translate_progress(
                    "wait_descriptor",
                    "Upload to {} started".format(args[3])
                )

        elif subtype == 'UPLOADED':
            # we only need ONE successful upload to happen for the
            # HS to be reachable.
            # unused? addr = args[1]

            # XXX FIXME I think tor is sending the onion-address
            # properly with these now, so we can use those
            # (i.e. instead of matching to "attempted_uploads")
            if args[3] in attempted_uploads:
                confirmed_uploads.add(args[3])
                log.msg("Uploaded '{}' to '{}'".format(args[1], args[3]))
                translate_progress(
                    "wait_descriptor",
                    "Successful upload to {}".format(args[3])
                )
                if not uploaded.called:
                    if await_all:
                        if (len(failed_uploads) + len(confirmed_uploads)) == len(attempted_uploads):
                            uploaded.callback(onion)
                    else:
                        uploaded.callback(onion)

        elif subtype == 'FAILED':
            if hostname_matches('{}.onion'.format(args[1])):
                failed_uploads.add(args[3])
                translate_progress(
                    "wait_descriptor",
                    "Failed upload to {}".format(args[3])
                )
                if failed_uploads == attempted_uploads:
                    msg = "Failed to upload '{}' to: {}".format(
                        args[1],
                        ', '.join(failed_uploads),
                    )
                    uploaded.errback(RuntimeError(msg))

    # the first 'yield' should be the add_event_listener so that a
    # caller can do "d = _await_descriptor_upload()", then add the
    # service.
    yield tor_protocol.add_event_listener('HS_DESC', hs_desc)
    yield uploaded
    yield tor_protocol.remove_event_listener('HS_DESC', hs_desc)
    # ensure we show "100%" at the end
    if progress:
        if await_all_uploads:
            msg = "Completed descriptor uploads"
        else:
            msg = "At least one descriptor uploaded"
        try:
            progress(100.0, "wait_descriptor", msg)
        except Exception:
            log.err()


@defer.inlineCallbacks
def _add_ephemeral_service(config, onion, progress, version, auth=None, await_all_uploads=None):
    """
    Internal Helper.

    This uses ADD_ONION to add the given service to Tor. The Deferred
    this returns will callback when the ADD_ONION call has succeed,
    *and* when at least one descriptor has been uploaded to a Hidden
    Service Directory.

    :param config: a TorConfig instance

    :param onion: an EphemeralOnionService instance

    :param progress: a callable taking 3 arguments (percent, tag,
        description) that is called some number of times to tell you of
        progress.

    :param version: 2 or 3, which kind of service to create

    :param auth: if not None, create an authenticated service ("basic"
        is the only kind supported currently so a AuthBasic instance
        should be passed)
    """
    if onion not in config.EphemeralOnionServices:
        config.EphemeralOnionServices.append(onion)

    # we have to keep this as a Deferred for now so that HS_DESC
    # listener gets added before we issue ADD_ONION
    assert version in (2, 3)
    uploaded_d = _await_descriptor_upload(config.tor_protocol, onion, progress, await_all_uploads)

    # we allow a key to be passed that *doestn'* start with
    # "RSA1024:" because having to escape the ":" for endpoint
    # string syntax (which uses ":" as delimeters) is annoying
    # XXX rethink ^^? what do we do when the type is upgraded?
    # maybe just a magic-character that's different from ":", or
    # force people to escape them?
    if onion.private_key:
        if onion.private_key is not DISCARD and ':' not in onion.private_key:
            if version == 2:
                if not onion.private_key.startswith("RSA1024:"):
                    onion._private_key = "RSA1024:" + onion.private_key
            elif version == 3:
                if not onion.private_key.startswith("ED25519-V3:"):
                    onion._private_key = "ED25519-V3:" + onion.private_key

    # okay, we're set up to listen, and now we issue the ADD_ONION
    # command. this will set ._hostname and ._private_key properly
    keystring = 'NEW:BEST'
    if onion.private_key not in (None, DISCARD):
        keystring = onion.private_key
    elif version == 3:
        keystring = 'NEW:ED25519-V3'
    if version == 3:
        if 'V3' not in keystring:
            raise ValueError(
                "version=3 but private key isn't 'ED25519-V3'"
            )

    # hmm, is it better to validate keyblob args in the create
    # methods? "Feels nicer" to see it here when building ADD_ONION
    # though?
    if '\r' in keystring or '\n' in keystring:
        raise ValueError(
            "No newline or return characters allowed in key blobs"
        )

    cmd = 'ADD_ONION {}'.format(keystring)
    for port in onion._ports:
        cmd += ' Port={},{}'.format(*port.split(' ', 1))
    flags = []
    if onion._detach:
        flags.append('Detach')
    if onion.private_key is DISCARD:
        flags.append('DiscardPK')
    if auth is not None:
        assert isinstance(auth, AuthBasic)  # don't support AuthStealth yet
        if isinstance(auth, AuthBasic):
            flags.append('BasicAuth')
    if onion._single_hop:
        flags.append('NonAnonymous')  # depends on some Tor options, too
    if flags:
        cmd += ' Flags={}'.format(','.join(flags))

    if auth is not None:
        for client_name in auth.client_names():
            keyblob = auth.keyblob_for(client_name)
            if keyblob is None:
                cmd += ' ClientAuth={}'.format(client_name)
            else:
                cmd += ' ClientAuth={}:{}'.format(client_name, keyblob)
                onion._add_client(client_name, keyblob)

    raw_res = yield config.tor_protocol.queue_command(cmd)
    res = find_keywords(raw_res.split('\n'))
    try:
        onion._hostname = res['ServiceID'] + '.onion'
        if onion.private_key is DISCARD:
            onion._private_key = None
        else:
            # if we specified a private key, it's not echoed back
            if not onion.private_key:
                onion._private_key = res['PrivateKey'].strip()
    except KeyError:
        raise RuntimeError(
            "Expected ADD_ONION to return ServiceID= and PrivateKey= args."
            "Got: {}".format(res)
        )

    if auth is not None:
        for line in raw_res.split('\n'):
            if line.startswith("ClientAuth="):
                name, blob = line[11:].split(':', 1)
                onion._add_client(name, blob)

    log.msg("{}: waiting for descriptor uploads.".format(onion.hostname))
    yield uploaded_d


class _AuthCommon(object):
    """
    Common code for all types of authentication
    """

    def __init__(self, clients):
        self._clients = dict()
        for client in clients:
            if isinstance(client, tuple):
                client_name, keyblob = client
                self._clients[client_name] = keyblob
            else:
                self._clients[client] = None
        if any(' ' in client for client in self._clients.keys()):
            raise ValueError("Client names can't have spaces")

    def client_names(self):
        return self._clients.keys()

    def keyblob_for(self, client_name):
        return self._clients[client_name]


class AuthBasic(_AuthCommon):
    """
    Authentication details for 'basic' auth.
    """
    auth_type = 'basic'
    # note that _AuthCommon.__init__ takes 'clients'


class AuthStealth(_AuthCommon):
    """
    Authentication details for 'stealth' auth.
    """
    auth_type = 'stealth'
    # note that _AuthCommon.__init__ takes 'clients'


DISCARD = object()


@implementer(IAuthenticatedOnionClients)
class EphemeralAuthenticatedOnionService(object):
    """
    An onion service with either 'stealth' or 'basic' authentication
    and keys stored in memory only (Tor doesn't store the private keys
    anywhere and erases them when shutting down).

    Use the async class-method ``create`` to make instances of this.
    """

    @staticmethod
    @defer.inlineCallbacks
    def create(reactor, config, ports,
               detach=False,
               private_key=None,  # or DISCARD or a key
               version=None,
               progress=None,
               auth=None,
               await_all_uploads=None,   # AuthBasic, or AuthStealth instance
               single_hop=False):

        """
        returns a new EphemeralAuthenticatedOnionService after adding it
        to the provided config and ensuring at least one of its
        descriptors is uploaded.

        :param config: a :class:`txtorcon.TorConfig` instance

        :param ports: a list of ports to make available; any of these
            can be 2-tuples of (remote, local) if you want to expose a
            particular port locally (otherwise, an available one is
            chosen)

        :param private_key: None, `DISCARD`, or a private key blob

        :param detach: if True, tell Tor to NOT associate this control
            connection with the lifetime of the created service

        :param version: 2 or 3, which kind of service to create

        :param progress: a callable taking (percent, tag, description)
            that is called periodically to report progress.

        :param await_all_uploads: if True, the Deferred only fires
            after ALL descriptor uploads have completed (otherwise, it
            fires when at least one has completed).

        :param single_hop: if True, pass the `NonAnonymous` flag. Note
            that Tor options `HiddenServiceSingleHopMode`,
            `HiddenServiceNonAnonymousMode` must be set to `1` and there
            must be no `SOCKSPort` configured for this to actually work.

        See also :meth:`txtorcon.Tor.create_onion_service` (which
        ultimately calls this).
        """
        if not isinstance(auth, (AuthBasic, AuthStealth)):
            raise ValueError(
                "'auth' should be an AuthBasic or AuthStealth instance"
            )

        if isinstance(auth, AuthStealth):
            raise ValueError(
                "Tor does not yet support ephemeral stealth-auth"
            )

        version = 2 if version is None else version
        assert version in (2, 3)

        processed_ports = yield _validate_ports(reactor, ports)

        onion = EphemeralAuthenticatedOnionService(
            config, processed_ports,
            private_key=private_key,
            detach=detach,
            version=version,
            single_hop=single_hop,
        )
        yield _add_ephemeral_service(config, onion, progress, version, auth, await_all_uploads)

        return onion

    def __init__(self, config, ports, hostname=None, private_key=None, auth=[], version=3,
                 detach=False, single_hop=None):
        """
        Users should create instances of this class by using the async
        method :meth:`txtorcon.EphemeralAuthenticatedOnionService.create`
        """

        _validate_ports_low_level(ports)

        self._config = config
        self._ports = ports
        self._hostname = hostname
        self._private_key = private_key
        self._version = version
        self._detach = detach
        self._clients = dict()
        self._single_hop = single_hop

    def get_permanent_id(self):
        """
        IAuthenticatedOnionClients API
        """
        assert '\n' not in self._private_key
        # why are we sometimes putting e.g. "RSA1024:xxxx" and
        # sometimes not? Should be one or the other
        if ':' in self._private_key:
            blob = self._private_key.split(':')[1].encode('ascii')
        else:
            blob = self._private_key.encode('ascii')
        keydata = b'-----BEGIN RSA PRIVATE KEY-----\n' + blob + b'\n-----END RSA PRIVATE KEY-----\n'
        # keydata = b'-----BEGIN PRIVATE KEY-----\n' + blob + b'\n-----END PRIVATE KEY-----\n'

        # XXX Hmm, it seems PyPy 5.8.0 *on travis* fails this (on my
        # system it works fine). Only relevant difference I can see is
        # openssl version 1.0.1f vs 1.0.1t
        private_key = serialization.load_pem_private_key(
            keydata,
            password=None,
            backend=default_backend(),
        )
        return _compute_permanent_id(private_key)

    def client_names(self):
        return self._clients.keys()

    def get_client(self, name):
        return self._clients[name]

    def _add_client(self, name, auth_token):
        self._clients[name] = EphemeralAuthenticatedOnionServiceClient(
            parent=self,
            name=name,
            token=auth_token,
        )

    @property
    def hostname(self):
        return self._hostname

    @property
    def ports(self):
        return set(self._ports)

    @property
    def version(self):
        return self._version

    @property
    def private_key(self):
        return self._private_key

    @defer.inlineCallbacks
    def remove(self):
        """
        Issues a DEL_ONION call to our tor, removing this service.
        """
        cmd = 'DEL_ONION {}'.format(self._hostname[:-len('.onion')])
        res = yield self._config.tor_protocol.queue_command(cmd)
        if res.strip() != "OK":
            raise RuntimeError("Failed to remove service")


@implementer(IOnionService)
class EphemeralOnionService(object):
    """
    An Onion service whose keys live in memory and are not persisted
    by Tor.

    It is up to the application developer to retrieve and store the
    private key if this service is ever to be brought online again.
    """

    @staticmethod
    @defer.inlineCallbacks
    def create(reactor, config, ports,
               detach=False,
               private_key=None,  # or DISCARD
               version=None,
               progress=None,
               await_all_uploads=None,
               single_hop=False):
        """
        returns a new EphemeralOnionService after adding it to the
        provided config and ensuring at least one of its descriptors
        is uploaded.

        :param config: a :class:`txtorcon.TorConfig` instance

        :param ports: a list of ports to make available; any of these
            can be 2-tuples of (remote, local) if you want to expose a
            particular port locally (otherwise, an available one is
            chosen)

        :param private_key: None, `DISCARD`, or a private key blob

        :param detach: if True, tell Tor to NOT associate this control
            connection with the lifetime of the created service

        :param version: 2 or 3, which kind of service to create

        :param progress: a callable taking (percent, tag, description)
            that is called periodically to report progress.

        :param await_all_uploads: if True, the Deferred only fires
            after ALL descriptor uploads have completed (otherwise, it
            fires when at least one has completed).

        :param single_hop: if True, pass the `NonAnonymous` flag. Note
            that Tor options `HiddenServiceSingleHopMode`,
            `HiddenServiceNonAnonymousMode` must be set to `1` and there
            must be no `SOCKSPort` configured for this to actually work.

        See also :meth:`txtorcon.Tor.create_onion_service` (which
        ultimately calls this).
        """
        version = 2 if version is None else version
        assert version in (2, 3)

        processed_ports = yield _validate_ports(reactor, ports)

        onion = EphemeralOnionService(
            config, processed_ports,
            hostname=None,
            private_key=private_key,
            detach=detach,
            version=version,
            await_all_uploads=await_all_uploads,
            single_hop=single_hop,
        )

        yield _add_ephemeral_service(config, onion, progress, version, None, await_all_uploads)

        return onion

    def __init__(self, config, ports, hostname=None, private_key=None, version=3,
                 detach=False, await_all_uploads=None, single_hop=None, **kwarg):
        """
        Users should create instances of this class by using the async
        method :meth:`txtorcon.EphemeralOnionService.create`
        """

        # prior to 17.0.0, this took an argument called "ver" instead
        # of "version". So, we will silently upgrade that.
        if "ver" in kwarg:
            version = int(kwarg.pop("ver"))
        # any other kwargs are illegal
        if len(kwarg):
            raise ValueError(
                "Unknown kwargs: {}".format(", ".join(kwarg.keys()))
            )

        _validate_ports_low_level(ports)

        self._config = config
        self._ports = ports
        self._hostname = hostname
        self._private_key = private_key
        self._version = version
        self._detach = detach
        self._single_hop = single_hop

    # not putting an "add_to_tor" method here; that class is now
    # deprecated and you add one of these by using .create()

    @defer.inlineCallbacks
    def remove(self):
        """
        Issues a DEL_ONION call to our tor, removing this service.
        """
        cmd = 'DEL_ONION {}'.format(self._hostname[:-len('.onion')])
        res = yield self._config.tor_protocol.queue_command(cmd)
        if res.strip() != "OK":
            raise RuntimeError("Failed to remove service")

    @property
    def ports(self):
        return set(self._ports)

    @property
    def version(self):
        return self._version

    @property
    def hostname(self):
        return self._hostname

    @property
    def private_key(self):
        return self._private_key


@implementer(IOnionClient)
class EphemeralAuthenticatedOnionServiceClient(object):
    """
    A single client of an EphemeralAuthenticatedOnionService

    These are only created by and returned from the .clients property
    of an AuthenticatedOnionService instance.
    """

    def __init__(self, parent, name, token):
        self._parent = parent
        self._name = name
        self._auth_token = token

    @property
    def name(self):
        return self._name

    @property
    def ports(self):
        return set(self._parent.ports)

    @property
    def hostname(self):
        return self._parent.hostname

    @property
    def auth_token(self):
        return self._auth_token

    @property
    def parent(self):
        return self._parent

    @property
    def version(self):
        return self._parent.version


@implementer(IOnionClient)
class FilesystemAuthenticatedOnionServiceClient(object):
    """
    A single client of an FilesystemAuthenticatedOnionService

    These are only created by and returned from the .clients property
    of an FilesystemAuthenticatedOnionService instance.
    """

    def __init__(self, parent, name, hostname, ports, token):
        self._parent = parent
        self._name = name
        self.hostname = hostname
        self.auth_token = token
        self.ephemeral = False
        self._ports = ports
        # XXX private_key?
        # XXX group_readable

    @property
    def name(self):
        return self._name

    @property
    def parent(self):
        return self._parent

    @property
    def ports(self):
        return self._ports

    @property
    def private_key(self):
        # yes, needs to come from "clients" file i think?
        return self._parent._private_key(self._name).key

    @property
    def group_readable(self):
        return self._parent.group_readable

    @property
    def authorize_client(self):
        return '{} {}'.format(self._name, self.auth_token)

    @property
    def hidden_service_directory(self):
        return self._parent.hidden_service_directory

    @property
    def version(self):
        return self._parent.version


def _compute_permanent_id(private_key):
    """
    Internal helper. Return an authenticated service's permanent ID
    given an RSA private key object.

    The permanent ID is the base32 encoding of the SHA1 hash of the
    first 10 bytes (80 bits) of the public key.
    """
    pub = private_key.public_key()
    p = pub.public_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PublicFormat.PKCS1
    )
    z = ''.join(p.decode('ascii').strip().split('\n')[1:-1])
    b = base64.b64decode(z)
    h1 = hashlib.new('sha1')
    h1.update(b)
    permanent_id = h1.digest()[:10]
    return base64.b32encode(permanent_id).lower().decode('ascii')


@implementer(IAuthenticatedOnionClients)
class FilesystemAuthenticatedOnionService(object):
    """
    An Onion service whose keys are stored on disk by Tor and which
    does authentication.
    """

    @staticmethod
    @defer.inlineCallbacks
    def create(reactor, config, hsdir, ports,
               auth=None,
               version=3,
               group_readable=False,
               progress=None,
               await_all_uploads=None):
        """
        returns a new FilesystemAuthenticatedOnionService after adding it
        to the provided config and ensureing at least one of its
        descriptors is uploaded.

        :param config: a :class:`txtorcon.TorConfig` instance

        :param ports: a list of ports to make available; any of these
            can be 2-tuples of (remote, local) if you want to expose a
            particular port locally (otherwise, an available one is
            chosen)

        :param auth: an instance of :class:`txtorcon.AuthBasic` or
            :class:`txtorcon.AuthStealth`

        :param version: 2 or 3, which kind of service to create

        :param group_readable: if True, the Tor option
            `HiddenServiceDirGroupReadable` is set to 1 for this service

        :param progress: a callable taking (percent, tag, description)
            that is called periodically to report progress.

        :param await_all_uploads: if True, the Deferred only fires
            after ALL descriptor uploads have completed (otherwise, it
            fires when at least one has completed).
        """
        # if hsdir is relative, it's "least surprising" (IMO) to make
        # it into a relative path here -- otherwise, it's relative to
        # whatever Tor's cwd is. Issue similar warning to Tor?
        hsdir = _canonical_hsdir(hsdir)
        processed_ports = yield _validate_ports(reactor, ports)

        fhs = FilesystemAuthenticatedOnionService(
            config, hsdir, processed_ports, auth,
            version=version,
            group_readable=group_readable,
        )
        config.HiddenServices.append(fhs)

        def translate_progress(pct, tag, description):
            # XXX fixme actually translate..
            if progress:
                progress(pct, tag, description)

        # most of this code same as non-authenticated version; can we share?
        # we .save() down below, after setting HS_DESC listener
        uploaded = [None]
        if not version_at_least(config.tor_protocol.version, 0, 2, 7, 2):
            translate_progress(
                102, "wait_desctiptor",
                "Adding an onion service to Tor requires at least version"
            )
            translate_progress(
                103, "wait_desctiptor",
                "0.2.7.2 so that HS_DESC events work properly and we can"
            )
            translate_progress(
                104, "wait_desctiptor",
                "detect our desctiptor being uploaded."
            )
            translate_progress(
                105, "wait_desctiptor",
                "Your version is '{}'".format(config.tor_protocol.version),
            )
            translate_progress(
                106, "wait_desctiptor",
                "So, we'll just declare it done right now..."
            )
            uploaded[0] = defer.succeed(None)
        else:
            # XXX actually, there's some versions of Tor when v3
            # filesystem services could be added but they didn't send
            # HS_DESC updates -- did any of these actually get
            # released?!
            uploaded[0] = _await_descriptor_upload(config.tor_protocol, fhs, progress, await_all_uploads)

        yield config.save()
        yield uploaded[0]
        return fhs

    def __init__(self, config, thedir, ports, auth, version=3, group_readable=0):
        # XXX do we need version here? probably...
        self._config = config
        self._dir = thedir
        self._ports = ports
        assert auth is not None, "Must provide an auth= instance"
        if not isinstance(auth, (AuthBasic, AuthStealth)):
            raise ValueError("auth= must be one of AuthBasic or AuthStealth")
        self._auth = auth
        # dict: name -> IAuthenticatedOnionClient
        self._clients = None
        self._expected_clients = auth.client_names()
        self._version = version
        self._group_readable = group_readable
        self._client_keys = None

    @property
    def hidden_service_directory(self):
        return self._dir

    @property
    def group_readable(self):
        return self._group_readable

    @property
    def ports(self):
        return self._ports

    @property
    def version(self):
        return self._version

    # basically everything in HiddenService, except the only API we
    # provide is "clients" because there's a separate .onion hostname
    # and authentication token per client.

    def get_permanent_id(self):
        """
        IAuthenticatedOnionClients API
        """
        with open(os.path.join(self._dir, "private_key"), "rb") as f:
            private_key = serialization.load_pem_private_key(
                f.read(),
                password=None,
                backend=default_backend(),
            )
        return _compute_permanent_id(private_key)

    def client_names(self):
        """
        IAuthenticatedOnionClients API
        """
        if self._clients is None:
            self._parse_hostname()
        return self._clients.keys()

    def get_client(self, name):
        """
        IAuthenticatedOnionClients API
        """
        if self._clients is None:
            self._parse_hostname()
        try:
            return self._clients[name]
        except KeyError:
            raise KeyError("No such client '{}'".format(name))

    def add_client(self, name, hostname, ports, token):
        if self._clients is None:
            self._parse_hostname()
        client = FilesystemAuthenticatedOnionServiceClient(
            parent=self,
            name=name,
            hostname=hostname,
            ports=ports, token=token,
        )
        self._clients[client.name] = client
        self._config.HiddenServices.append(client)

    def _private_key(self, name):
        if self._client_keys is None:
            self._parse_client_keys()
        return self._client_keys[name]

    def _parse_client_keys(self):
        try:
            with open(os.path.join(self._dir, 'client_keys'), 'r') as f:
                keys = _parse_client_keys(f)
        except IOError:
            keys = []
        self._client_keys = {}
        for auth in keys:
            self._client_keys[auth.name] = auth

    def _parse_hostname(self):
        clients = {}
        try:
            with open(os.path.join(self._dir, 'hostname')) as f:
                for idx, line in enumerate(f.readlines()):
                    # lines are like: hex.onion hex # client: name
                    m = re.match("(.*) (.*) # client: (.*)", line)
                    hostname, cookie, name = m.groups()
                    # -> for auth'd services we end up with multiple
                    # -> HiddenService instances now (because different
                    # -> hostnames)
                    clients[name] = FilesystemAuthenticatedOnionServiceClient(
                        self, name, hostname,
                        ports=self._ports,
                        token=cookie,
                    )
        except IOError:
            self._clients = dict()
            return

        self._clients = clients
        if self._expected_clients:
            for expected in self._expected_clients:
                if expected not in self._clients:
                    raise RuntimeError(
                        "Didn't find expected client '{}'".format(expected)
                    )

    def config_attributes(self):
        """
        Helper method used by TorConfig when generating a torrc file and
        SETCONF commands
        """

        rtn = [('HiddenServiceDir', str(self._dir))]
        if self._config._supports['HiddenServiceDirGroupReadable'] \
           and self.group_readable:
            rtn.append(('HiddenServiceDirGroupReadable', str(1)))
        for port in self.ports:
            rtn.append(('HiddenServicePort', str(port)))
        if self._version:
            rtn.append(('HiddenServiceVersion', str(self._version)))
        if self._clients:
            rtn.append((
                'HiddenServiceAuthorizeClient',
                "{} {}".format(self._auth.auth_type, ','.join(self.client_names()))
            ))
        else:
            rtn.append((
                'HiddenServiceAuthorizeClient',
                "{} {}".format(self._auth.auth_type, ','.join(self._expected_clients))
            ))
        return rtn


@defer.inlineCallbacks
def _validate_ports(reactor, ports):
    """
    Internal helper for Onion services. Validates an incoming list of
    port mappings and returns a list of strings suitable for passing
    to other onion-services functions.

    Accepts 3 different ways of specifying ports:

      - list of ints: each int is the public port, local port random
      - list of 2-tuples of ints: (pubic, local) ports.
      - list of strings like "80 127.0.0.1:1234"

    This is async in case it needs to ask for a random, unallocated
    local port.
    """
    if not isinstance(ports, (list, tuple)):
        raise ValueError("'ports' must be a list of strings, ints or 2-tuples")

    processed_ports = []
    for port in ports:
        if isinstance(port, (set, list, tuple)):
            if len(port) != 2:
                raise ValueError(
                    "'ports' must contain a single int or a 2-tuple of ints"
                )
            remote, local = port
            try:
                remote = int(remote)
            except ValueError:
                raise ValueError(
                    "'ports' has a tuple with a non-integer "
                    "component: {}".format(port)
                )
            try:
                local = int(local)
            except ValueError:
                if local.startswith('unix:/'):
                    pass
                else:
                    if ':' not in local:
                        raise ValueError(
                            "local port must be either an integer"
                            " or start with unix:/ or be an IP:port"
                        )
                    ip, port = local.split(':')
                    if not _is_non_public_numeric_address(ip):
                        log.msg(
                            "'{}' used as onion port doesn't appear to be a "
                            "local, numeric address".format(ip)
                        )
                processed_ports.append(
                    "{} {}".format(remote, local)
                )
            else:
                processed_ports.append(
                    "{} 127.0.0.1:{}".format(remote, local)
                )

        elif isinstance(port, str):
            _validate_single_port_string(port)
            processed_ports.append(port)

        else:
            try:
                remote = int(port)
            except (ValueError, TypeError):
                raise ValueError(
                    "'ports' has a non-integer entry: {}".format(port)
                )
            local = yield available_tcp_port(reactor)
            processed_ports.append(
                "{} 127.0.0.1:{}".format(remote, local)
            )
    return processed_ports


def _validate_ports_low_level(ports):
    """
    Internal helper.

    Validates the 'ports' argument to EphemeralOnionService or
    EphemeralAuthenticatedOnionService returning None on success or
    raising ValueError otherwise.

    This only accepts the "list of strings" variants; some
    higher-level APIs also allow lists of ints or lists of 2-tuples,
    but those must be converted to strings before they get here.
    """
    if not isinstance(ports, (list, tuple)):
        raise ValueError("'ports' must be a list of strings")
    if any([not isinstance(x, str) for x in ports]):
        raise ValueError("'ports' must be a list of strings")
    for port in ports:
        _validate_single_port_string(port)


def _validate_single_port_string(port):
    """
    Validate a single string specifying ports for Onion
    services. These look like: "80 127.0.0.1:4321"
    """
    if ' ' not in port or len(port.split(' ')) != 2:
        raise ValueError(
            "Port '{}' should have exactly one space in it".format(port)
        )
    (external, internal) = port.split(' ')
    try:
        external = int(external)
    except ValueError:
        raise ValueError(
            "Port '{}' external port isn't an int".format(port)
        )
    if ':' not in internal:
        raise ValueError(
            "Port '{}' local address should be 'IP:port'".format(port)
        )
    if not internal.startswith('unix:'):
        ip, localport = internal.split(':')
        if ip != 'localhost' and not _is_non_public_numeric_address(ip):
            raise ValueError(
                "Port '{}' internal IP '{}' should be a local "
                "address".format(port, ip)
            )


def _parse_rsa_blob(lines):
    '''
    Internal helper.
    '''
    return 'RSA1024:' + ''.join(lines[1:-1])


def _parse_client_keys(stream):
    '''
    This parses a hidden-service "client_keys" file, either stealth or
    basic (they're the same, except "stealth" includes a
    "client-key"). Returns a list of HiddenServiceClientAuth() instances.

    Note that the key does NOT include the "----BEGIN ---" markers,
    nor *any* embedded whitespace. It is *just* the key blob.

    '''

    def parse_error(data):
        raise RuntimeError("Parse error at: " + data)

    class ParserState(object):
        def __init__(self):
            self.keys = []
            self.reset()

        def reset(self):
            self.name = None
            self.cookie = None
            self.key = []

        def create_key(self):
            if self.name is not None:
                self.keys.append(HiddenServiceClientAuth(self.name, self.cookie, self.key))
            self.reset()

        def set_name(self, name):
            self.create_key()
            self.name = name.split()[1]

        def set_cookie(self, cookie):
            self.cookie = cookie.split()[1]
            if self.cookie.endswith('=='):
                self.cookie = self.cookie[:-2]

        def add_key_line(self, line):
            self.key.append(line)

    from txtorcon.spaghetti import FSM, State, Transition
    init = State('init')
    got_name = State('got_name')
    got_cookie = State('got_cookie')
    reading_key = State('got_key')

    parser_state = ParserState()

    # initial state; we want "client-name" or it's an error
    init.add_transitions([
        Transition(got_name, lambda line: line.startswith('client-name '), parser_state.set_name),
        Transition(init, lambda line: not line.startswith('client-name '), parse_error),
    ])

    # next up is "descriptor-cookie" or it's an error
    got_name.add_transitions([
        Transition(got_cookie, lambda line: line.startswith('descriptor-cookie '), parser_state.set_cookie),
        Transition(init, lambda line: not line.startswith('descriptor-cookie '), parse_error),
    ])

    # the "interesting bit": there's either a client-name if we're a
    # "basic" file, or an RSA key (with "client-key" before it)
    got_cookie.add_transitions([
        Transition(reading_key, lambda line: line.startswith('client-key'), None),
        Transition(got_name, lambda line: line.startswith('client-name '), parser_state.set_name),
    ])

    # if we're reading an RSA key, we accumulate it in current_key.key
    # until we hit a line starting with "client-name"
    reading_key.add_transitions([
        Transition(reading_key, lambda line: not line.startswith('client-name'), parser_state.add_key_line),
        Transition(got_name, lambda line: line.startswith('client-name '), parser_state.set_name),
    ])

    # create our FSM and parse the data
    fsm = FSM([init, got_name, got_cookie, reading_key])
    for line in stream.readlines():
        fsm.process(line.strip())

    parser_state.create_key()  # make sure we get the "last" one
    return parser_state.keys
