#!/usr/bin/env python3

# Copyright (C) 2009-2022 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 typing import Dict, Any
import time
from copy import deepcopy

from twisted.words.protocols.jabber import xmlstream, jid
from twisted.words.xish import domish
from twisted.internet import defer
from wokkel import disco
from zope.interface import implementer

from libervia.backend.core.constants import Const as C
from libervia.backend.core.i18n import _, D_
from libervia.backend.core import exceptions
from libervia.backend.core.core_types import SatXMPPEntity
from libervia.backend.core.log import getLogger
from libervia.backend.memory.sqla_mapping import History

log = getLogger(__name__)


PLUGIN_INFO = {
    C.PI_NAME: "Message Retraction",
    C.PI_IMPORT_NAME: "XEP-0424",
    C.PI_TYPE: "XEP",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0334", "XEP-0424", "XEP-0428"],
    C.PI_DEPENDENCIES: ["XEP-0422"],
    C.PI_MAIN: "XEP_0424",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation Message Retraction"""),
}

NS_MESSAGE_RETRACT = "urn:xmpp:message-retract:0"

CATEGORY = "Privacy"
NAME = "retract_history"
LABEL = D_("Keep History of Retracted Messages")
PARAMS = """
    <params>
    <individual>
    <category name="{category_name}">
        <param name="{name}" label="{label}" type="bool" value="false" />
    </category>
    </individual>
    </params>
    """.format(
    category_name=CATEGORY, name=NAME, label=_(LABEL)
)


class XEP_0424(object):

    def __init__(self, host):
        log.info(_("XEP-0424 (Message Retraction) plugin initialization"))
        self.host = host
        host.memory.update_params(PARAMS)
        self._h = host.plugins["XEP-0334"]
        self._f = host.plugins["XEP-0422"]
        host.register_namespace("message-retract", NS_MESSAGE_RETRACT)
        host.trigger.add("message_received", self._message_received_trigger, 100)
        host.bridge.add_method(
            "message_retract",
            ".plugin",
            in_sign="ss",
            out_sign="",
            method=self._retract,
            async_=True,
        )

    def get_handler(self, __):
        return XEP_0424_handler()

    def _retract(self, message_id: str, profile: str) -> None:
        client = self.host.get_client(profile)
        return defer.ensureDeferred(
            self.retract(client, message_id)
        )

    def retract_by_origin_id(
        self,
        client: SatXMPPEntity,
        dest_jid: jid.JID,
        origin_id: str
    ) -> None:
        """Send a message retraction using origin-id

        [retract] should be prefered: internal ID should be used as it is independant of
        XEPs changes. However, in some case messages may not be stored in database
        (notably for some components), and then this method can be used
        @param origin_id: origin-id as specified in XEP-0359
        """
        message_elt = domish.Element((None, "message"))
        message_elt["from"] = client.jid.full()
        message_elt["to"] = dest_jid.full()
        apply_to_elt = self._f.apply_to_elt(message_elt, origin_id)
        apply_to_elt.addElement((NS_MESSAGE_RETRACT, "retract"))
        self.host.plugins["XEP-0428"].add_fallback_elt(
            message_elt,
            "[A message retraction has been requested, but your client doesn't support "
            "it]"
        )
        self._h.add_hint_elements(message_elt, [self._h.HINT_STORE])
        client.send(message_elt)

    async def retract_by_history(
        self,
        client: SatXMPPEntity,
        history: History
    ) -> None:
        """Send a message retraction using History instance

        This method is to use instead of [retract] when the history instance is already
        retrieved. Note that the instance must have messages and subjets loaded
        @param history: history instance of the message to retract
        """
        try:
            origin_id = history.origin_id
        except KeyError:
            raise exceptions.FeatureNotFound(
                f"message to retract doesn't have the necessary origin-id, the sending "
                "client is probably not supporting message retraction."
            )
        else:
            self.retract_by_origin_id(client, history.dest_jid, origin_id)
            await self.retract_db_history(client, history)

    async def retract(
        self,
        client: SatXMPPEntity,
        message_id: str,
    ) -> None:
        """Send a message retraction request

        @param message_id: ID of the message
            This ID is the Libervia internal ID of the message. It will be retrieve from
            database to find the ID used by XMPP (i.e. XEP-0359's "origin ID"). If the
            message is not found in database, an exception will be raised
        """
        if not message_id:
            raise ValueError("message_id can't be empty")
        history = await self.host.memory.storage.get(
            client, History, History.uid, message_id,
            joined_loads=[History.messages, History.subjects]
        )
        if history is None:
            raise exceptions.NotFound(
                f"message to retract not found in database ({message_id})"
            )
        await self.retract_by_history(client, history)

    async def retract_db_history(self, client, history: History) -> None:
        """Mark an history instance in database as retracted

        @param history: history instance
            "messages" and "subjects" must be loaded too
        """
        # FIXME: should be keep history? This is useful to check why a message has been
        #   retracted, but if may be bad if the user think it's really deleted
        # we assign a new object to be sure to trigger an update
        history.extra = deepcopy(history.extra) if history.extra else {}
        history.extra["retracted"] = True
        keep_history = self.host.memory.param_get_a(
            NAME, CATEGORY, profile_key=client.profile
        )
        old_version: Dict[str, Any] = {
            "timestamp": time.time()
        }
        if keep_history:
            old_version.update({
                "messages": [m.serialise() for m in history.messages],
                "subjects": [s.serialise() for s in history.subjects]
            })

        history.extra.setdefault("old_versions", []).append(old_version)
        await self.host.memory.storage.delete(
            history.messages + history.subjects,
            session_add=[history]
        )

    async def _message_received_trigger(
        self,
        client: SatXMPPEntity,
        message_elt: domish.Element,
        post_treat: defer.Deferred
    ) -> bool:
        fastened_elts = await self._f.get_fastened_elts(client, message_elt)
        if fastened_elts is None:
            return True
        for elt in fastened_elts.elements:
            if elt.name == "retract" and elt.uri == NS_MESSAGE_RETRACT:
                if fastened_elts.history is not None:
                    source_jid = fastened_elts.history.source_jid
                    from_jid = jid.JID(message_elt["from"])
                    if source_jid.userhostJID() != from_jid.userhostJID():
                        log.warning(
                            f"Received message retraction from {from_jid.full()}, but "
                            f"the message to retract is from {source_jid.full()}. This "
                            f"maybe a hack attempt.\n{message_elt.toXml()}"
                        )
                        return False
                break
        else:
            return True
        if not await self.host.trigger.async_point(
            "XEP-0424_retractReceived", client, message_elt, elt, fastened_elts
        ):
            return False
        if fastened_elts.history is None:
            # we check history after the trigger because we may be in a component which
            # doesn't store messages in database.
            log.warning(
                f"No message found with given origin-id: {message_elt.toXml()}"
            )
            return False
        log.info(f"[{client.profile}] retracting message {fastened_elts.id!r}")
        await self.retract_db_history(client, fastened_elts.history)
        # TODO: send bridge signal

        return False


@implementer(disco.IDisco)
class XEP_0424_handler(xmlstream.XMPPHandler):

    def getDiscoInfo(self, __, target, nodeIdentifier=""):
        return [disco.DiscoFeature(NS_MESSAGE_RETRACT)]

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