#!/usr/bin/env python3


# SAT plugin for Message Archive Management (XEP-0313)
# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)
# Copyright (C) 2013-2016 Adrien Cossa (souliane@mailoo.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 datetime import datetime
import uuid

from dateutil import tz
from twisted.internet import defer
from twisted.words.protocols.jabber import jid
from twisted.words.protocols.jabber.error import StanzaError
from wokkel import disco
from wokkel import data_form
from wokkel import rsm
from wokkel import mam
from zope.interface import implementer

from libervia.backend.core import exceptions
from libervia.backend.core.constants import Const as C
from libervia.backend.core.i18n import _
from libervia.backend.core.log import getLogger
from libervia.backend.tools import xml_tools
from libervia.backend.tools.common import data_format


log = getLogger(__name__)

PLUGIN_INFO = {
    C.PI_NAME: "Message Archive Management",
    C.PI_IMPORT_NAME: "XEP-0313",
    C.PI_TYPE: "XEP",
    # XEP-0431 only defines a namespace, so we register it here
    C.PI_PROTOCOLS: ["XEP-0313", "XEP-0431"],
    C.PI_DEPENDENCIES: ["XEP-0059", "XEP-0359"],
    C.PI_MAIN: "XEP_0313",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation of Message Archive Management"""),
}

MAM_PREFIX = "mam_"
FILTER_PREFIX = MAM_PREFIX + "filter_"
KEY_LAST_STANZA_ID = "last_stanza_id"
MESSAGE_RESULT = "/message/result[@xmlns='{mam_ns}' and @queryid='{query_id}']"
MESSAGE_STANZA_ID = '/message/stanza-id[@xmlns="{ns_stanza_id}"]'
NS_FTS = "urn:xmpp:fulltext:0"


class XEP_0313(object):
    def __init__(self, host):
        log.info(_("Message Archive Management plugin initialization"))
        self.host = host
        self.host.register_namespace("mam", mam.NS_MAM)
        host.register_namespace("fulltextmam", NS_FTS)
        self._rsm = host.plugins["XEP-0059"]
        self._sid = host.plugins["XEP-0359"]
        # Deferred used to store last stanza id in order of reception
        self._last_stanza_id_d = defer.Deferred()
        self._last_stanza_id_d.callback(None)
        host.bridge.add_method(
            "mam_get", ".plugin", in_sign='sss',
            out_sign='(a(sdssa{ss}a{ss}ss)ss)', method=self._get_archives,
            async_=True)

    async def resume(self, client):
        """Retrieve one2one messages received since the last we have in local storage"""
        stanza_id_data = await self.host.memory.storage.get_privates(
            mam.NS_MAM, [KEY_LAST_STANZA_ID], profile=client.profile)
        stanza_id = stanza_id_data.get(KEY_LAST_STANZA_ID)
        rsm_req = None
        if stanza_id is None:
            log.info("can't retrieve last stanza ID, checking history")
            last_mess = await self.host.memory.history_get(
                None, None, limit=1, filters={'not_types': C.MESS_TYPE_GROUPCHAT,
                                              'last_stanza_id': True},
                profile=client.profile)
            if not last_mess:
                log.info(_("It seems that we have no MAM history yet"))
                stanza_id = None
                rsm_req = rsm.RSMRequest(max_=50, before="")
            else:
                stanza_id = last_mess[0][-1]['stanza_id']
        if rsm_req is None:
            rsm_req = rsm.RSMRequest(max_=100, after=stanza_id)
        mam_req = mam.MAMRequest(rsm_=rsm_req)
        complete = False
        count = 0
        while not complete:
            try:
                mam_data = await self.get_archives(client, mam_req,
                                                  service=client.jid.userhostJID())
            except StanzaError as e:
                log.warning(
                    f"Can't retrieve MAM archives: {e}\n"
                    f"{xml_tools.pp_elt(mam_req.toElement())}\n"
                    f"{xml_tools.pp_elt(e.stanza)}"
                )
                return
            except Exception as e:
                log.exception(
                    f"Can't retrieve retrieve MAM archive"
                )
                return
            elt_list, rsm_response, mam_response = mam_data
            complete = mam_response["complete"]
            # we update MAM request for next iteration
            mam_req.rsm.after = rsm_response.last
            # before may be set if we had no previous history
            mam_req.rsm.before = None
            if not elt_list:
                break
            else:
                count += len(elt_list)

            for idx, mess_elt in enumerate(elt_list):
                try:
                    fwd_message_elt = self.get_message_from_result(
                        client, mess_elt, mam_req)
                except exceptions.DataError:
                    continue

                try:
                    destinee = jid.JID(fwd_message_elt['to'])
                except KeyError:
                    log.warning(_('missing "to" attribute in forwarded message'))
                    destinee = client.jid
                if destinee.userhostJID() == client.jid.userhostJID():
                    # message to use, we insert the forwarded message in the normal
                    # workflow
                    client.xmlstream.dispatch(fwd_message_elt)
                else:
                    # this message should be from us, we just add it to history
                    try:
                        from_jid = jid.JID(fwd_message_elt['from'])
                    except KeyError:
                        log.warning(_('missing "from" attribute in forwarded message'))
                        from_jid = client.jid
                    if from_jid.userhostJID() != client.jid.userhostJID():
                        log.warning(_(
                            'was expecting a message sent by our jid, but this one if '
                            'from {from_jid}, ignoring\n{xml}').format(
                                from_jid=from_jid.full(), xml=mess_elt.toXml()))
                        continue
                    # adding message to history
                    mess_data = client.messageProt.parse_message(fwd_message_elt)
                    try:
                        await client.messageProt.add_to_history(mess_data)
                    except exceptions.CancelError as e:
                        log.warning(
                            "message has not been added to history: {e}".format(e=e))
                    except Exception as e:
                        log.error(
                            "can't add message to history: {e}\n{xml}"
                            .format(e=e, xml=mess_elt.toXml()))
                    if complete and idx == len(elt_list) - 1:
                        # We are at the last message from archive, we store the ID to not
                        # ask again the same messages next time.
                        try:
                            stanza_id = mess_elt.result["id"]
                            await self.host.memory.storage.set_private_value(
                                namespace=mam.NS_MAM,
                                key=KEY_LAST_STANZA_ID,
                                value=stanza_id,
                                profile=client.profile
                            )
                        except Exception:
                            log.exception("Can't store last stanza ID")

        if not count:
            log.info(_("We have received no message while offline"))
        else:
            log.info(_("We have received {num_mess} message(s) while offline.")
                .format(num_mess=count))

    def profile_connected(self, client):
        defer.ensureDeferred(self.resume(client))

    def get_handler(self, client):
        mam_client = client._mam = LiberviaMAMClient(self)
        return mam_client

    def parse_extra(self, extra, with_rsm=True):
        """Parse extra dictionnary to retrieve MAM arguments

        @param extra(dict): data for parse
        @param with_rsm(bool): if True, RSM data will be parsed too
        @return (data_form, None): request with parsed arguments
            or None if no MAM arguments have been found
        """
        mam_args = {}
        form_args = {}
        for arg in ("start", "end"):
            try:
                value = extra.pop(MAM_PREFIX + arg)
                form_args[arg] = datetime.fromtimestamp(float(value), tz.tzutc())
            except (TypeError, ValueError):
                log.warning("Bad value for {arg} filter ({value}), ignoring".format(
                    arg=arg, value=value))
            except KeyError:
                continue

        try:
            form_args["with_jid"] = jid.JID(extra.pop(
                MAM_PREFIX + "with"))
        except (jid.InvalidFormat):
            log.warning("Bad value for jid filter")
        except KeyError:
            pass

        for name, value in extra.items():
            if name.startswith(FILTER_PREFIX):
                var = name[len(FILTER_PREFIX):]
                extra_fields = form_args.setdefault("extra_fields", [])
                extra_fields.append(data_form.Field(var=var, value=value))

        for arg in ("node", "query_id"):
            try:
                value = extra.pop(MAM_PREFIX + arg)
                mam_args[arg] = value
            except KeyError:
                continue

        if with_rsm:
            rsm_request = self._rsm.parse_extra(extra)
            if rsm_request is not None:
                mam_args["rsm_"] = rsm_request

        if form_args:
            mam_args["form"] = mam.buildForm(**form_args)

        # we only set orderBy if we have other MAM args
        # else we would make a MAM query while it's not expected
        if "order_by" in extra and mam_args:
            order_by = extra.pop("order_by")
            assert isinstance(order_by, list)
            mam_args["orderBy"] = order_by

        return mam.MAMRequest(**mam_args) if mam_args else None

    def get_message_from_result(self, client, mess_elt, mam_req, service=None):
        """Extract usable <message/> from MAM query result

        The message will be validated, and stanza-id/delay will be added if necessary.
        @param mess_elt(domish.Element): result <message/> element wrapping the message
            to retrieve
        @param mam_req(mam.MAMRequest): request used (needed to get query_id)
        @param service(jid.JID, None): MAM service where the request has been sent
            None if it's user server
        @return domish.Element): <message/> that can be used directly with onMessage
        """
        if mess_elt.name != "message":
            log.warning("unexpected stanza in archive: {xml}".format(
                xml=mess_elt.toXml()))
            raise exceptions.DataError("Invalid element")
        service_jid = client.jid.userhostJID() if service is None else service
        mess_from = mess_elt.getAttribute("from") or client.jid.userhost()
        # we check that the message has been sent by the right service
        # if service is None (i.e. message expected from our own server)
        # from can be server jid or user's bare jid
        if (mess_from != service_jid.full()
            and not (service is None and mess_from == client.jid.host)):
            log.error("Message is not from our server, something went wrong: "
                      "{xml}".format(xml=mess_elt.toXml()))
            raise exceptions.DataError("Invalid element")
        try:
            result_elt = next(mess_elt.elements(mam.NS_MAM, "result"))
            forwarded_elt = next(result_elt.elements(C.NS_FORWARD, "forwarded"))
            try:
                delay_elt = next(forwarded_elt.elements(C.NS_DELAY, "delay"))
            except StopIteration:
                # delay_elt is not mandatory
                delay_elt = None
            fwd_message_elt = next(forwarded_elt.elements(C.NS_CLIENT, "message"))
        except StopIteration:
            log.warning("Invalid message received from MAM: {xml}".format(
                xml=mess_elt.toXml()))
            raise exceptions.DataError("Invalid element")
        else:
            if not result_elt["queryid"] == mam_req.query_id:
                log.error("Unexpected query id (was expecting {query_id}): {xml}"
                    .format(query_id=mam.query_id, xml=mess_elt.toXml()))
                raise exceptions.DataError("Invalid element")
            stanza_id = self._sid.get_stanza_id(fwd_message_elt,
                                              service_jid)
            if stanza_id is None:
                # not stanza-id element is present, we add one so message
                # will be archived with it, and we won't request several times
                # the same MAM achive
                try:
                    stanza_id = result_elt["id"]
                except AttributeError:
                    log.warning('Invalid MAM result: missing "id" attribute: {xml}'
                                .format(xml=result_elt.toXml()))
                    raise exceptions.DataError("Invalid element")
                self._sid.add_stanza_id(client, fwd_message_elt, stanza_id, by=service_jid)

            if delay_elt is not None:
                fwd_message_elt.addChild(delay_elt)

            return fwd_message_elt

    def queryFields(self, client, service=None):
        """Ask the server about supported fields.

        @param service: entity offering the MAM service (None for user archives)
        @return (D(data_form.Form)): form with the implemented fields (cf XEP-0313 §4.1.5)
        """
        return client._mam.queryFields(service)

    def queryArchive(self, client, mam_req, service=None):
        """Query a user, MUC or pubsub archive.

        @param mam_req(mam.MAMRequest): MAM query instance
        @param service(jid.JID, None): entity offering the MAM service
            None for user server
        @return (D(domish.Element)): <IQ/> result
        """
        return client._mam.queryArchive(mam_req, service)

    def _append_message(self, elt_list, message_cb, message_elt):
        if message_cb is not None:
            elt_list.append(message_cb(message_elt))
        else:
            elt_list.append(message_elt)

    def _query_finished(self, iq_result, client, elt_list, event):
        client.xmlstream.removeObserver(event, self._append_message)
        try:
            fin_elt = next(iq_result.elements(mam.NS_MAM, "fin"))
        except StopIteration:
            raise exceptions.DataError("Invalid MAM result")

        mam_response = {"complete": C.bool(fin_elt.getAttribute("complete", C.BOOL_FALSE)),
                        "stable": C.bool(fin_elt.getAttribute("stable", C.BOOL_TRUE))}

        try:
            rsm_response = rsm.RSMResponse.fromElement(fin_elt)
        except rsm.RSMNotFoundError:
            rsm_response = None

        return (elt_list, rsm_response, mam_response)

    def serialize_archive_result(self, data, client, mam_req, service):
        elt_list, rsm_response, mam_response = data
        mess_list = []
        for elt in elt_list:
            fwd_message_elt = self.get_message_from_result(client, elt, mam_req,
                                                        service=service)
            mess_data = client.messageProt.parse_message(fwd_message_elt)
            mess_list.append(client.message_get_bridge_args(mess_data))
        metadata = {
            'rsm': self._rsm.response2dict(rsm_response),
            'mam': mam_response
        }
        return mess_list, data_format.serialise(metadata), client.profile

    def _get_archives(self, service, extra_ser, profile_key):
        """
        @return: tuple with:
            - list of message with same data as in bridge.message_new
            - response metadata with:
                - rsm data (first, last, count, index)
                - mam data (complete, stable)
            - profile
        """
        client = self.host.get_client(profile_key)
        service = jid.JID(service) if service else None
        extra = data_format.deserialise(extra_ser, {})
        mam_req = self.parse_extra(extra)

        d = self.get_archives(client, mam_req, service=service)
        d.addCallback(self.serialize_archive_result, client, mam_req, service)
        return d

    def get_archives(self, client, query, service=None, message_cb=None):
        """Query archive and gather page result

        @param query(mam.MAMRequest): MAM request
        @param service(jid.JID, None): MAM service to use
            None to use our own server
        @param message_cb(callable, None): callback to use on each message
            this method can be used to unwrap messages
        @return (tuple[list[domish.Element], rsm.RSMResponse, dict): result data with:
            - list of found elements
            - RSM response
            - MAM response, which is a dict with following value:
                - complete: a boolean which is True if all items have been received
                - stable: a boolean which is False if items order may be changed
        """
        if query.query_id is None:
            query.query_id = str(uuid.uuid4())
        elt_list = []
        event = MESSAGE_RESULT.format(mam_ns=mam.NS_MAM, query_id=query.query_id)
        client.xmlstream.addObserver(event, self._append_message, 0, elt_list, message_cb)
        d = self.queryArchive(client, query, service)
        d.addCallback(self._query_finished, client, elt_list, event)
        return d

    def get_prefs(self, client, service=None):
        """Retrieve the current user preferences.

        @param service: entity offering the MAM service (None for user archives)
        @return: the server response as a Deferred domish.Element
        """
        # http://xmpp.org/extensions/xep-0313.html#prefs
        return client._mam.queryPrefs(service)

    def _set_prefs(self, service_s=None, default="roster", always=None, never=None,
                  profile_key=C.PROF_KEY_NONE):
        service = jid.JID(service_s) if service_s else None
        always_jid = [jid.JID(entity) for entity in always]
        never_jid = [jid.JID(entity) for entity in never]
        # TODO: why not build here a MAMPrefs object instead of passing the args separately?
        return self.setPrefs(service, default, always_jid, never_jid, profile_key)

    def setPrefs(self, client, service=None, default="roster", always=None, never=None):
        """Set news user preferences.

        @param service: entity offering the MAM service (None for user archives)
        @param default (unicode): a value in ('always', 'never', 'roster')
        @param always (list): a list of JID instances
        @param never (list): a list of JID instances
        @param profile_key (unicode): %(doc_profile_key)s
        @return: the server response as a Deferred domish.Element
        """
        # http://xmpp.org/extensions/xep-0313.html#prefs
        return client._mam.setPrefs(service, default, always, never)

    def on_message_stanza_id(self, message_elt, client):
        """Called when a message with a stanza-id is received

        the messages' stanza ids are stored when received, so the last one can be used
        to retrieve missing history on next connection
        @param message_elt(domish.Element): <message> with a stanza-id
        """
        if message_elt.getAttribute("type") == C.MESS_TYPE_GROUPCHAT:
            # groupchat message MAM is handled by XEP-0045
            return
        service_jid = client.jid.userhostJID()
        stanza_id = self._sid.get_stanza_id(message_elt, service_jid)
        if stanza_id is None:
            log.debug("Ignoring <message>, stanza id is not from our server")
        else:
            # we use self._last_stanza_id_d do be sure that last_stanza_id is stored in
            # the order of reception
            self._last_stanza_id_d.addCallback(
                lambda __: self.host.memory.storage.set_private_value(
                    namespace=mam.NS_MAM,
                    key=KEY_LAST_STANZA_ID,
                    value=stanza_id,
                    profile=client.profile))


@implementer(disco.IDisco)
class LiberviaMAMClient(mam.MAMClient):

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

    @property
    def host(self):
        return self.parent.host_app

    def connectionInitialized(self):
        observer_xpath = MESSAGE_STANZA_ID.format(
            ns_stanza_id=self.host.ns_map['stanza_id'])
        self.xmlstream.addObserver(
            observer_xpath, self.plugin_parent.on_message_stanza_id, client=self.parent
        )

    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
        return [disco.DiscoFeature(mam.NS_MAM)]

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