#!/usr/bin/env python3


# SAT plugin for Ad-Hoc Commands (XEP-0050)
# Copyright (C) 2009-2020 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


from collections import namedtuple
from uuid import uuid4
from typing import List, Optional

from zope.interface import implementer
from twisted.words.protocols.jabber import jid
from twisted.words.protocols import jabber
from twisted.words.protocols.jabber.xmlstream import XMPPHandler
from twisted.words.xish import domish
from twisted.internet import defer
from wokkel import disco, iwokkel, data_form
from sat.core.i18n import _, D_
from sat.core.constants import Const as C
from sat.core.log import getLogger
from sat.core.xmpp import SatXMPPEntity
from sat.core import exceptions
from sat.memory.memory import Sessions
from sat.tools import xml_tools
from sat.tools.common import data_format


log = getLogger(__name__)


IQ_SET = '/iq[@type="set"]'
NS_COMMANDS = "http://jabber.org/protocol/commands"
ID_CMD_LIST = disco.DiscoIdentity("automation", "command-list")
ID_CMD_NODE = disco.DiscoIdentity("automation", "command-node")
CMD_REQUEST = IQ_SET + '/command[@xmlns="' + NS_COMMANDS + '"]'

SHOWS = {
    "default": _("Online"),
    "away": _("Away"),
    "chat": _("Free for chat"),
    "dnd": _("Do not disturb"),
    "xa": _("Left"),
    "disconnect": _("Disconnect"),
}

PLUGIN_INFO = {
    C.PI_NAME: "Ad-Hoc Commands",
    C.PI_IMPORT_NAME: "XEP-0050",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_TYPE: "XEP",
    C.PI_PROTOCOLS: ["XEP-0050"],
    C.PI_MAIN: "XEP_0050",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation of Ad-Hoc Commands"""),
}


class AdHocError(Exception):
    def __init__(self, error_const):
        """ Error to be used from callback
        @param error_const: one of XEP_0050.ERROR
        """
        assert error_const in XEP_0050.ERROR
        self.callback_error = error_const


@implementer(iwokkel.IDisco)
class AdHocCommand(XMPPHandler):

    def __init__(self, callback, label, node, features, timeout,
                 allowed_jids, allowed_groups, allowed_magics, forbidden_jids,
                forbidden_groups):
        XMPPHandler.__init__(self)
        self.callback = callback
        self.label = label
        self.node = node
        self.features = [disco.DiscoFeature(feature) for feature in features]
        (
            self.allowed_jids,
            self.allowed_groups,
            self.allowed_magics,
            self.forbidden_jids,
            self.forbidden_groups,
        ) = (
            allowed_jids,
            allowed_groups,
            allowed_magics,
            forbidden_jids,
            forbidden_groups,
        )
        self.sessions = Sessions(timeout=timeout)

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

    def getName(self, xml_lang=None):
        return self.label

    def isAuthorised(self, requestor):
        if "@ALL@" in self.allowed_magics:
            return True
        forbidden = set(self.forbidden_jids)
        for group in self.forbidden_groups:
            forbidden.update(self.client.roster.getJidsFromGroup(group))
        if requestor.userhostJID() in forbidden:
            return False
        allowed = set(self.allowed_jids)
        for group in self.allowed_groups:
            try:
                allowed.update(self.client.roster.getJidsFromGroup(group))
            except exceptions.UnknownGroupError:
                log.warning(_("The groups [{group}] is unknown for profile [{profile}])")
                            .format(group=group, profile=self.client.profile))
        if requestor.userhostJID() in allowed:
            return True
        return False

    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
        if (
            nodeIdentifier != NS_COMMANDS
        ):  # FIXME: we should manage other disco nodes here
            return []
        # identities = [ID_CMD_LIST if self.node == NS_COMMANDS else ID_CMD_NODE] # FIXME
        return [disco.DiscoFeature(NS_COMMANDS)] + self.features

    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
        return []

    def _sendAnswer(self, callback_data, session_id, request):
        """ Send result of the command

        @param callback_data: tuple (payload, status, actions, note) with:
            - payload (domish.Element, None) usualy containing data form
            - status: current status, see XEP_0050.STATUS
            - actions(list[str], None): list of allowed actions (see XEP_0050.ACTION).
                       First action is the default one. Default to EXECUTE
            - note(tuple[str, unicode]): optional additional note: either None or a
                tuple with (note type, human readable string), "note type" being in
                XEP_0050.NOTE
        @param session_id: current session id
        @param request: original request (domish.Element)
        @return: deferred
        """
        payload, status, actions, note = callback_data
        assert isinstance(payload, domish.Element) or payload is None
        assert status in XEP_0050.STATUS
        if not actions:
            actions = [XEP_0050.ACTION.EXECUTE]
        result = domish.Element((None, "iq"))
        result["type"] = "result"
        result["id"] = request["id"]
        result["to"] = request["from"]
        command_elt = result.addElement("command", NS_COMMANDS)
        command_elt["sessionid"] = session_id
        command_elt["node"] = self.node
        command_elt["status"] = status

        if status != XEP_0050.STATUS.CANCELED:
            if status != XEP_0050.STATUS.COMPLETED:
                actions_elt = command_elt.addElement("actions")
                actions_elt["execute"] = actions[0]
                for action in actions:
                    actions_elt.addElement(action)

            if note is not None:
                note_type, note_mess = note
                note_elt = command_elt.addElement("note", content=note_mess)
                note_elt["type"] = note_type

            if payload is not None:
                command_elt.addChild(payload)

        self.client.send(result)
        if status in (XEP_0050.STATUS.COMPLETED, XEP_0050.STATUS.CANCELED):
            del self.sessions[session_id]

    def _sendError(self, error_constant, session_id, request):
        """ Send error stanza

        @param error_constant: one of XEP_OO50.ERROR
        @param request: original request (domish.Element)
        """
        xmpp_condition, cmd_condition = error_constant
        iq_elt = jabber.error.StanzaError(xmpp_condition).toResponse(request)
        if cmd_condition:
            error_elt = next(iq_elt.elements(None, "error"))
            error_elt.addElement(cmd_condition, NS_COMMANDS)
        self.client.send(iq_elt)
        del self.sessions[session_id]

    def _requestEb(self, failure_, request, session_id):
        if failure_.check(AdHocError):
            error_constant = failure.value.callback_error
        else:
            log.error(f"unexpected error while handling request: {failure_}")
            error_constant = XEP_0050.ERROR.INTERNAL

        self._sendError(error_constant, session_id, request)

    def onRequest(self, command_elt, requestor, action, session_id):
        if not self.isAuthorised(requestor):
            return self._sendError(
                XEP_0050.ERROR.FORBIDDEN, session_id, command_elt.parent
            )
        if session_id:
            try:
                session_data = self.sessions[session_id]
            except KeyError:
                return self._sendError(
                    XEP_0050.ERROR.SESSION_EXPIRED, session_id, command_elt.parent
                )
            if session_data["requestor"] != requestor:
                return self._sendError(
                    XEP_0050.ERROR.FORBIDDEN, session_id, command_elt.parent
                )
        else:
            session_id, session_data = self.sessions.newSession()
            session_data["requestor"] = requestor
        if action == XEP_0050.ACTION.CANCEL:
            d = defer.succeed((None, XEP_0050.STATUS.CANCELED, None, None))
        else:
            d = defer.maybeDeferred(
                self.callback,
                self.client,
                command_elt,
                session_data,
                action,
                self.node,
            )
        d.addCallback(self._sendAnswer, session_id, command_elt.parent)
        d.addErrback(self._requestEb, command_elt.parent, session_id)


class XEP_0050(object):
    STATUS = namedtuple("Status", ("EXECUTING", "COMPLETED", "CANCELED"))(
        "executing", "completed", "canceled"
    )
    ACTION = namedtuple("Action", ("EXECUTE", "CANCEL", "NEXT", "PREV"))(
        "execute", "cancel", "next", "prev"
    )
    NOTE = namedtuple("Note", ("INFO", "WARN", "ERROR"))("info", "warn", "error")
    ERROR = namedtuple(
        "Error",
        (
            "MALFORMED_ACTION",
            "BAD_ACTION",
            "BAD_LOCALE",
            "BAD_PAYLOAD",
            "BAD_SESSIONID",
            "SESSION_EXPIRED",
            "FORBIDDEN",
            "ITEM_NOT_FOUND",
            "FEATURE_NOT_IMPLEMENTED",
            "INTERNAL",
        ),
    )(
        ("bad-request", "malformed-action"),
        ("bad-request", "bad-action"),
        ("bad-request", "bad-locale"),
        ("bad-request", "bad-payload"),
        ("bad-request", "bad-sessionid"),
        ("not-allowed", "session-expired"),
        ("forbidden", None),
        ("item-not-found", None),
        ("feature-not-implemented", None),
        ("internal-server-error", None),
    )  # XEP-0050 §4.4 Table 5

    def __init__(self, host):
        log.info(_("plugin XEP-0050 initialization"))
        self.host = host
        self.requesting = Sessions()
        host.bridge.addMethod(
            "adHocRun",
            ".plugin",
            in_sign="sss",
            out_sign="s",
            method=self._run,
            async_=True,
        )
        host.bridge.addMethod(
            "adHocList",
            ".plugin",
            in_sign="ss",
            out_sign="s",
            method=self._listUI,
            async_=True,
        )
        host.bridge.addMethod(
            "adHocSequence",
            ".plugin",
            in_sign="ssss",
            out_sign="s",
            method=self._sequence,
            async_=True,
        )
        self.__requesting_id = host.registerCallback(
            self._requestingEntity, with_data=True
        )
        host.importMenu(
            (D_("Service"), D_("Commands")),
            self._commandsMenu,
            security_limit=2,
            help_string=D_("Execute ad-hoc commands"),
        )
        host.registerNamespace('commands', NS_COMMANDS)

    def getHandler(self, client):
        return XEP_0050_handler(self)

    def profileConnected(self, client):
        # map from node to AdHocCommand instance
        client._XEP_0050_commands = {}
        if not client.is_component:
            self.addAdHocCommand(client, self._statusCallback, _("Status"))

    def do(self, client, entity, node, action=ACTION.EXECUTE, session_id=None,
           form_values=None, timeout=30):
        """Do an Ad-Hoc Command

        @param entity(jid.JID): entity which will execture the command
        @param node(unicode): node of the command
        @param action(unicode): one of XEP_0050.ACTION
        @param session_id(unicode, None): id of the ad-hoc session
            None if no session is involved
        @param form_values(dict, None): values to use to create command form
            values will be passed to data_form.Form.makeFields
        @return: iq result element
        """
        iq_elt = client.IQ(timeout=timeout)
        iq_elt["to"] = entity.full()
        command_elt = iq_elt.addElement("command", NS_COMMANDS)
        command_elt["node"] = node
        command_elt["action"] = action
        if session_id is not None:
            command_elt["sessionid"] = session_id

        if form_values:
            # We add the XMLUI result to the command payload
            form = data_form.Form("submit")
            form.makeFields(form_values)
            command_elt.addChild(form.toElement())
        d = iq_elt.send()
        return d

    def getCommandElt(self, iq_elt):
        try:
            return next(iq_elt.elements(NS_COMMANDS, "command"))
        except StopIteration:
            raise exceptions.NotFound(_("Missing command element"))

    def adHocError(self, error_type):
        """Shortcut to raise an AdHocError

        @param error_type(unicode): one of XEP_0050.ERROR
        """
        raise AdHocError(error_type)

    def _items2XMLUI(self, items, no_instructions):
        """Convert discovery items to XMLUI dialog """
        # TODO: manage items on different jids
        form_ui = xml_tools.XMLUI("form", submit_id=self.__requesting_id)

        if not no_instructions:
            form_ui.addText(_("Please select a command"), "instructions")

        options = [(item.nodeIdentifier, item.name) for item in items]
        form_ui.addList("node", options)
        return form_ui

    def _getDataLvl(self, type_):
        """Return the constant corresponding to <note/> type attribute value

        @param type_: note type (see XEP-0050 §4.3)
        @return: a C.XMLUI_DATA_LVL_* constant
        """
        if type_ == "error":
            return C.XMLUI_DATA_LVL_ERROR
        elif type_ == "warn":
            return C.XMLUI_DATA_LVL_WARNING
        else:
            if type_ != "info":
                log.warning(_("Invalid note type [%s], using info") % type_)
            return C.XMLUI_DATA_LVL_INFO

    def _mergeNotes(self, notes):
        """Merge notes with level prefix (e.g. "ERROR: the message")

        @param notes (list): list of tuple (level, message)
        @return: list of messages
        """
        lvl_map = {
            C.XMLUI_DATA_LVL_INFO: "",
            C.XMLUI_DATA_LVL_WARNING: "%s: " % _("WARNING"),
            C.XMLUI_DATA_LVL_ERROR: "%s: " % _("ERROR"),
        }
        return ["%s%s" % (lvl_map[lvl], msg) for lvl, msg in notes]

    def parseCommandAnswer(self, iq_elt):
        command_elt = self.getCommandElt(iq_elt)
        data = {}
        data["status"] = command_elt.getAttribute("status", XEP_0050.STATUS.EXECUTING)
        data["session_id"] = command_elt.getAttribute("sessionid")
        data["notes"] = notes = []
        for note_elt in command_elt.elements(NS_COMMANDS, "note"):
            notes.append(
                (
                    self._getDataLvl(note_elt.getAttribute("type", "info")),
                    str(note_elt),
                )
            )

        return command_elt, data


    def _commandsAnswer2XMLUI(self, iq_elt, session_id, session_data):
        """Convert command answer to an ui for frontend

        @param iq_elt: command result
        @param session_id: id of the session used with the frontend
        @param profile_key: %(doc_profile_key)s
        """
        command_elt, answer_data = self.parseCommandAnswer(iq_elt)
        status = answer_data["status"]
        if status in [XEP_0050.STATUS.COMPLETED, XEP_0050.STATUS.CANCELED]:
            # the command session is finished, we purge our session
            del self.requesting[session_id]
            if status == XEP_0050.STATUS.COMPLETED:
                session_id = None
            else:
                return None
        remote_session_id = answer_data["session_id"]
        if remote_session_id:
            session_data["remote_id"] = remote_session_id
        notes = answer_data["notes"]
        for data_elt in command_elt.elements(data_form.NS_X_DATA, "x"):
            if data_elt["type"] in ("form", "result"):
                break
        else:
            # no matching data element found
            if status != XEP_0050.STATUS.COMPLETED:
                log.warning(
                    _("No known payload found in ad-hoc command result, aborting")
                )
                del self.requesting[session_id]
                return xml_tools.XMLUI(
                    C.XMLUI_DIALOG,
                    dialog_opt={
                        C.XMLUI_DATA_TYPE: C.XMLUI_DIALOG_NOTE,
                        C.XMLUI_DATA_MESS: _("No payload found"),
                        C.XMLUI_DATA_LVL: C.XMLUI_DATA_LVL_ERROR,
                    },
                )
            if not notes:
                # the status is completed, and we have no note to show
                return None

            # if we have only one note, we show a dialog with the level of the note
            # if we have more, we show a dialog with "info" level, and all notes merged
            dlg_level = notes[0][0] if len(notes) == 1 else C.XMLUI_DATA_LVL_INFO
            return xml_tools.XMLUI(
                C.XMLUI_DIALOG,
                dialog_opt={
                    C.XMLUI_DATA_TYPE: C.XMLUI_DIALOG_NOTE,
                    C.XMLUI_DATA_MESS: "\n".join(self._mergeNotes(notes)),
                    C.XMLUI_DATA_LVL: dlg_level,
                },
                session_id=session_id,
            )

        if session_id is None:
            return xml_tools.dataFormEltResult2XMLUI(data_elt)
        form = data_form.Form.fromElement(data_elt)
        # we add any present note to the instructions
        form.instructions.extend(self._mergeNotes(notes))
        return xml_tools.dataForm2XMLUI(form, self.__requesting_id, session_id=session_id)

    def _requestingEntity(self, data, profile):
        def serialise(ret_data):
            if "xmlui" in ret_data:
                ret_data["xmlui"] = ret_data["xmlui"].toXml()
            return ret_data

        d = self.requestingEntity(data, profile)
        d.addCallback(serialise)
        return d

    def requestingEntity(self, data, profile):
        """Request and entity and create XMLUI accordingly.

        @param data: data returned by previous XMLUI (first one must come from
                     self._commandsMenu)
        @param profile: %(doc_profile)s
        @return: callback dict result (with "xmlui" corresponding to the answering
                 dialog, or empty if it's finished without error)
        """
        if C.bool(data.get("cancelled", C.BOOL_FALSE)):
            return defer.succeed({})
        data_form_values = xml_tools.XMLUIResult2DataFormResult(data)
        client = self.host.getClient(profile)
        # TODO: cancel, prev and next are not managed
        # TODO: managed answerer errors
        # TODO: manage nodes with a non data form payload
        if "session_id" not in data:
            # we just had the jid, we now request it for the available commands
            session_id, session_data = self.requesting.newSession(profile=client.profile)
            entity = jid.JID(data[xml_tools.SAT_FORM_PREFIX + "jid"])
            session_data["jid"] = entity
            d = self.listUI(client, entity)

            def sendItems(xmlui):
                xmlui.session_id = session_id  # we need to keep track of the session
                return {"xmlui": xmlui}

            d.addCallback(sendItems)
        else:
            # we have started a several forms sessions
            try:
                session_data = self.requesting.profileGet(
                    data["session_id"], client.profile
                )
            except KeyError:
                log.warning("session id doesn't exist, session has probably expired")
                # TODO: send error dialog
                return defer.succeed({})
            session_id = data["session_id"]
            entity = session_data["jid"]
            try:
                session_data["node"]
                # node has already been received
            except KeyError:
                # it's the first time we know the node, we save it in session data
                session_data["node"] = data_form_values.pop("node")

            # remote_id is the XEP_0050 sessionid used by answering command
            # while session_id is our own session id used with the frontend
            remote_id = session_data.get("remote_id")

            # we request execute node's command
            d = self.do(client, entity, session_data["node"], action=XEP_0050.ACTION.EXECUTE,
                        session_id=remote_id, form_values=data_form_values)
            d.addCallback(self._commandsAnswer2XMLUI, session_id, session_data)
            d.addCallback(lambda xmlui: {"xmlui": xmlui} if xmlui is not None else {})

        return d

    def _commandsMenu(self, menu_data, profile):
        """First XMLUI activated by menu: ask for target jid

        @param profile: %(doc_profile)s
        """
        form_ui = xml_tools.XMLUI("form", submit_id=self.__requesting_id)
        form_ui.addText(_("Please enter target jid"), "instructions")
        form_ui.changeContainer("pairs")
        form_ui.addLabel("jid")
        form_ui.addString("jid", value=self.host.getClient(profile).jid.host)
        return {"xmlui": form_ui.toXml()}

    def _statusCallback(self, client, command_elt, session_data, action, node):
        """Ad-hoc command used to change the "show" part of status"""
        actions = session_data.setdefault("actions", [])
        actions.append(action)

        if len(actions) == 1:
            # it's our first request, we ask the desired new status
            status = XEP_0050.STATUS.EXECUTING
            form = data_form.Form("form", title=_("status selection"))
            show_options = [
                data_form.Option(name, label) for name, label in list(SHOWS.items())
            ]
            field = data_form.Field(
                "list-single", "show", options=show_options, required=True
            )
            form.addField(field)

            payload = form.toElement()
            note = None

        elif len(actions) == 2:
            # we should have the answer here
            try:
                x_elt = next(command_elt.elements(data_form.NS_X_DATA, "x"))
                answer_form = data_form.Form.fromElement(x_elt)
                show = answer_form["show"]
            except (KeyError, StopIteration):
                self.adHocError(XEP_0050.ERROR.BAD_PAYLOAD)
            if show not in SHOWS:
                self.adHocError(XEP_0050.ERROR.BAD_PAYLOAD)
            if show == "disconnect":
                self.host.disconnect(client.profile)
            else:
                self.host.setPresence(show=show, profile_key=client.profile)

            # job done, we can end the session
            status = XEP_0050.STATUS.COMPLETED
            payload = None
            note = (self.NOTE.INFO, _("Status updated"))
        else:
            self.adHocError(XEP_0050.ERROR.INTERNAL)

        return (payload, status, None, note)

    def _run(self, service_jid_s="", node="", profile_key=C.PROF_KEY_NONE):
        client = self.host.getClient(profile_key)
        service_jid = jid.JID(service_jid_s) if service_jid_s else None
        d = self.run(client, service_jid, node or None)
        d.addCallback(lambda xmlui: xmlui.toXml())
        return d

    @defer.inlineCallbacks
    def run(self, client, service_jid=None, node=None):
        """Run an ad-hoc command

        @param service_jid(jid.JID, None): jid of the ad-hoc service
            None to use profile's server
        @param node(unicode, None): node of the ad-hoc commnad
            None to get initial list
        @return(unicode): command page XMLUI
        """
        if service_jid is None:
            service_jid = jid.JID(client.jid.host)
        session_id, session_data = self.requesting.newSession(profile=client.profile)
        session_data["jid"] = service_jid
        if node is None:
            xmlui = yield self.listUI(client, service_jid)
        else:
            session_data["node"] = node
            cb_data = yield self.requestingEntity(
                {"session_id": session_id}, client.profile
            )
            xmlui = cb_data["xmlui"]

        xmlui.session_id = session_id
        defer.returnValue(xmlui)

    def list(self, client, to_jid):
        """Request available commands

        @param to_jid(jid.JID, None): the entity answering the commands
            None to use profile's server
        @return D(disco.DiscoItems): found commands
        """
        d = self.host.getDiscoItems(client, to_jid, NS_COMMANDS)
        return d

    def _listUI(self, to_jid_s, profile_key):
        client = self.host.getClient(profile_key)
        to_jid = jid.JID(to_jid_s) if to_jid_s else None
        d = self.listUI(client, to_jid, no_instructions=True)
        d.addCallback(lambda xmlui: xmlui.toXml())
        return d

    def listUI(self, client, to_jid, no_instructions=False):
        """Request available commands and generate XMLUI

        @param to_jid(jid.JID, None): the entity answering the commands
            None to use profile's server
        @param no_instructions(bool): if True, don't add instructions widget
        @return D(xml_tools.XMLUI): UI with the commands
        """
        d = self.list(client, to_jid)
        d.addCallback(self._items2XMLUI, no_instructions)
        return d

    def _sequence(self, sequence, node, service_jid_s="", profile_key=C.PROF_KEY_NONE):
        sequence = data_format.deserialise(sequence, type_check=list)
        client = self.host.getClient(profile_key)
        service_jid = jid.JID(service_jid_s) if service_jid_s else None
        d = defer.ensureDeferred(self.sequence(client, sequence, node, service_jid))
        d.addCallback(lambda data: data_format.serialise(data))
        return d

    async def sequence(
        self,
        client: SatXMPPEntity,
        sequence: List[dict],
        node: str,
        service_jid: Optional[jid.JID] = None,
    ) -> dict:
        """Send a series of data to an ad-hoc service

        @param sequence: list of
        @param node: node of the ad-hoc commnad
        @param service_jid: jid of the ad-hoc service
            None to use profile's server
        @return: data received in final answer
        """
        if service_jid is None:
            service_jid = jid.JID(client.jid.host)

        session_id = None

        for data_to_send in sequence:
            iq_result_elt = await self.do(
                client,
                service_jid,
                node,
                session_id=session_id,
                form_values=data_to_send,
            )
            __, answer_data = self.parseCommandAnswer(iq_result_elt)
            session_id = answer_data.pop("session_id")

        return answer_data

    def addAdHocCommand(self, client, callback, label, node=None, features=None,
                        timeout=600, allowed_jids=None, allowed_groups=None,
                        allowed_magics=None, forbidden_jids=None, forbidden_groups=None,
                        ):
        """Add an ad-hoc command for the current profile

        @param callback: method associated with this ad-hoc command which return the
                         payload data (see AdHocCommand._sendAnswer), can return a
                         deferred
        @param label: label associated with this command on the main menu
        @param node: disco item node associated with this command. None to use
                     autogenerated node
        @param features: features associated with the payload (list of strings), usualy
                         data form
        @param timeout: delay between two requests before canceling the session (in
                        seconds)
        @param allowed_jids: list of allowed entities
        @param allowed_groups: list of allowed roster groups
        @param allowed_magics: list of allowed magic keys, can be:
                               @ALL@: allow everybody
                               @PROFILE_BAREJID@: allow only the jid of the profile
        @param forbidden_jids: black list of entities which can't access this command
        @param forbidden_groups: black list of groups which can't access this command
        @return: node of the added command, useful to remove the command later
        """
        # FIXME: "@ALL@" for profile_key seems useless and dangerous

        if node is None:
            node = "%s_%s" % ("COMMANDS", uuid4())

        if features is None:
            features = [data_form.NS_X_DATA]

        if allowed_jids is None:
            allowed_jids = []
        if allowed_groups is None:
            allowed_groups = []
        if allowed_magics is None:
            allowed_magics = ["@PROFILE_BAREJID@"]
        if forbidden_jids is None:
            forbidden_jids = []
        if forbidden_groups is None:
            forbidden_groups = []

        # TODO: manage newly created/removed profiles
        _allowed_jids = (
            (allowed_jids + [client.jid.userhostJID()])
            if "@PROFILE_BAREJID@" in allowed_magics
            else allowed_jids
        )
        ad_hoc_command = AdHocCommand(
            callback,
            label,
            node,
            features,
            timeout,
            _allowed_jids,
            allowed_groups,
            allowed_magics,
            forbidden_jids,
            forbidden_groups,
        )
        ad_hoc_command.setHandlerParent(client)
        commands = client._XEP_0050_commands
        commands[node] = ad_hoc_command

    def onCmdRequest(self, request, client):
        request.handled = True
        requestor = jid.JID(request["from"])
        command_elt = next(request.elements(NS_COMMANDS, "command"))
        action = command_elt.getAttribute("action", self.ACTION.EXECUTE)
        node = command_elt.getAttribute("node")
        if not node:
            client.sendError(request, "bad-request")
            return
        sessionid = command_elt.getAttribute("sessionid")
        commands = client._XEP_0050_commands
        try:
            command = commands[node]
        except KeyError:
            client.sendError(request, "item-not-found")
            return
        command.onRequest(command_elt, requestor, action, sessionid)


@implementer(iwokkel.IDisco)
class XEP_0050_handler(XMPPHandler):

    def __init__(self, plugin_parent):
        self.plugin_parent = plugin_parent

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

    def connectionInitialized(self):
        self.xmlstream.addObserver(
            CMD_REQUEST, self.plugin_parent.onCmdRequest, client=self.parent
        )

    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
        identities = []
        if nodeIdentifier == NS_COMMANDS and self.client._XEP_0050_commands:
            # we only add the identity if we have registred commands
            identities.append(ID_CMD_LIST)
        return [disco.DiscoFeature(NS_COMMANDS)] + identities

    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
        ret = []
        if nodeIdentifier == NS_COMMANDS:
            commands = self.client._XEP_0050_commands
            for command in list(commands.values()):
                if command.isAuthorised(requestor):
                    ret.append(
                        disco.DiscoItem(self.parent.jid, command.node, command.getName())
                    )  # TODO: manage name language
        return ret