#!/usr/bin/env python3

# Copyright (C) 2009-2023 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/>.

import time

from sqlalchemy.orm.attributes import flag_modified
from twisted.internet import defer
from twisted.words.protocols.jabber import xmlstream
from twisted.words.protocols.jabber import jid
from twisted.words.xish import domish
from wokkel import disco
from zope.interface import implementer

from libervia.backend.core import exceptions
from libervia.backend.core.constants import Const as C
from libervia.backend.core.core_types import SatXMPPEntity
from libervia.backend.core.i18n import _
from libervia.backend.core.log import getLogger
from libervia.backend.memory.sqla import History, Message, Subject, joinedload, select
from libervia.backend.models.core import MessageData, MessageEdition
from libervia.backend.tools.common import data_format
from libervia.backend.tools.utils import aio
log = getLogger(__name__)


PLUGIN_INFO = {
    C.PI_NAME: "Last Message Correction",
    C.PI_IMPORT_NAME: "XEP-0308",
    C.PI_TYPE: "XEP",
    C.PI_PROTOCOLS: ["XEP-0308"],
    C.PI_DEPENDENCIES: ["XEP-0334"],
    C.PI_MAIN: "XEP_0308",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation of XEP-0308 (Last Message Correction)"""),
}

NS_MESSAGE_CORRECT = "urn:xmpp:message-correct:0"


class XEP_0308:
    def __init__(self, host):
        log.info(f"plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization")
        self.host = host
        host.register_namespace("message_correct", NS_MESSAGE_CORRECT)
        host.trigger.add("message_received", self._message_received_trigger)
        host.bridge.add_method(
            "message_edit",
            ".plugin",
            in_sign="sss",
            out_sign="",
            method=self._message_edit,
            async_=True,
        )
        self._h = host.plugins["XEP-0334"]

    def get_handler(self, client):
        return XEP_0308_handler()

    @aio
    async def get_last_history(
        self, client: SatXMPPEntity, message_elt: domish.Element
    ) -> History | None:
        profile_id = self.host.memory.storage.profiles[client.profile]
        from_jid = jid.JID(message_elt["from"])
        message_type = message_elt.getAttribute("type", C.MESS_TYPE_NORMAL)
        async with self.host.memory.storage.session() as session:
            stmt = (
                select(History)
                .where(
                    History.profile_id == profile_id,
                    History.source == from_jid.userhost(),
                    History.type == message_type,
                )
                .options(joinedload(History.messages))
                .options(joinedload(History.subjects))
                .options(joinedload(History.thread))
            )
            if message_elt.type == C.MESS_TYPE_GROUPCHAT:
                stmt = stmt.where(History.source_res == from_jid.resource)

            # we want last message
            stmt = stmt.order_by(History.timestamp.desc()).limit(1)
            result = await session.execute(stmt)
            history = result.unique().scalar_one_or_none()
        return history

    async def update_history(
        self,
        client: SatXMPPEntity,
        edited_history: History,
        edit_timestamp: float,
        new_message: dict[str, str],
        new_subject: dict[str, str],
        new_extra: dict,
        previous_message: dict[str, str],
        previous_subject: dict[str, str],
        previous_extra: dict | None,
        store: bool = True,
    ) -> None:
        # FIXME: new_extra is not handled by now
        edited_history.messages = [
            Message(message=mess, language=lang) for lang, mess in new_message.items()
        ]
        edited_history.subjects = [
            Subject(subject=mess, language=lang) for lang, mess in new_subject.items()
        ]
        previous_version = {
            # this is the timestamp when this version was published
            "timestamp": edited_history.extra.get("updated", edited_history.timestamp),
            "message": previous_message,
            "subject": previous_subject,
        }
        edited_history.extra["updated"] = edit_timestamp
        if previous_extra:
            previous_extra = previous_extra.copy()
            # we must not have editions in each edition
            try:
                del previous_extra[C.MESS_EXTRA_EDITIONS]
            except KeyError:
                pass
            # extra may be important for rich content
            previous_version["extra"] = previous_extra

        if store:
            flag_modified(edited_history, "extra")
            edited_history.extra.setdefault(C.MESS_EXTRA_EDITIONS, []).append(previous_version)
            await self.host.memory.storage.add(edited_history)

            edit_data = MessageData(edited_history.serialise())
            self.host.bridge.message_update(
                edited_history.uid,
                C.MESS_UPDATE_EDIT,
                data_format.serialise(edit_data),
                client.profile,
            )

    async def _message_received_trigger(
        self,
        client: SatXMPPEntity,
        message_elt: domish.Element,
        post_treat: defer.Deferred,
    ) -> bool:
        replace_elt = next(message_elt.elements(NS_MESSAGE_CORRECT, "replace"), None)
        if not replace_elt:
            return True
        try:
            replace_id = replace_elt["id"].strip()
            if not replace_id:
                raise KeyError
        except KeyError:
            log.warning(f"Invalid message correction: {message_elt.toXml()}")
        else:
            edited_history = await self.get_last_history(client, message_elt)
            if edited_history is None:
                log.warning(
                    f"No message found from {message_elt['from']}, can't correct "
                    f"anything: {message_elt.toXml()}"
                )
                return False
            if edited_history.extra.get("message_id") != replace_id:
                log.warning(
                    "Can't apply correction: it doesn't reference the last one: "
                    f"{message_elt.toXml}"
                )
                return False
            previous_message_data = edited_history.serialise()
            message_data = client.messageProt.parse_message(message_elt)
            if not message_data["message"] and not message_data["subject"]:
                log.warning(
                    "Message correction doesn't have body not subject, we can't edit "
                    "anything"
                )
                return False

            await self.update_history(
                client,
                edited_history,
                message_data.get("received_timestamp") or message_data["timestamp"],
                message_data["message"],
                message_data["subject"],
                message_data["extra"],
                previous_message_data["message"],
                previous_message_data["subject"],
                previous_message_data.get("extra"),
            )

        return False

    async def message_edit(
        self,
        client: SatXMPPEntity,
        message_id: str,
        edit_data: MessageEdition,
    ) -> None:
        """Edit a message

        The message can only be edited if it's the last one of the discussion.
        @param client: client instance
        @param message_id: UID of the message to edit
        @param edit_data: data to update in the message
        """
        timestamp = time.time()
        edited_history = await self.host.memory.storage.get(
            client,
            History,
            History.uid,
            message_id,
            joined_loads=[History.messages, History.subjects, History.thread],
        )
        if edited_history is None:
            raise exceptions.NotFound(
                f"message to edit not found in database ({message_id})"
            )
        if edited_history.type == C.MESS_TYPE_GROUPCHAT:
            is_group_chat = True
            peer_jid = edited_history.dest_jid
        else:
            is_group_chat = False
            peer_jid = jid.JID(edited_history.dest)
        history_data = await self.host.memory.history_get(
            client.jid, peer_jid, limit=1, profile=client.profile
        )
        if not history_data:
            raise exceptions.NotFound(
                "No message found in conversation with {peer_jid.full()}"
            )
        last_mess = history_data[0]
        if last_mess[0] != message_id:
            raise ValueError(
                f"{message_id} is not the last message of the discussion, we can't edit "
                "it"
            )

        await self.update_history(
            client,
            edited_history,
            timestamp,
            edit_data.message,
            edit_data.subject,
            edit_data.extra,
            last_mess[4],
            last_mess[5],
            last_mess[-1],
            # message will be updated and signal sent on reception in group chat
            store = not is_group_chat
        )

        serialised = edited_history.serialise()
        serialised["from"] = jid.JID(serialised["from"])
        serialised["to"] = jid.JID(serialised["to"])

        message_elt = client.generate_message_xml(serialised)["xml"]
        replace_elt = message_elt.addElement((NS_MESSAGE_CORRECT, "replace"))
        replace_elt["id"] = message_id
        self._h.add_hint_elements(message_elt, [self._h.HINT_STORE])
        client.send(message_elt)

    def _message_edit(self, message_id: str, edit_data_s: str, profile: str) -> None:
        client = self.host.get_client(profile)
        edit_data = MessageEdition.model_validate_json(edit_data_s)
        defer.ensureDeferred(self.message_edit(client, message_id, edit_data))


@implementer(disco.IDisco)
class XEP_0308_handler(xmlstream.XMPPHandler):
    def getDiscoInfo(self, __, target, nodeIdentifier=""):
        return [disco.DiscoFeature(NS_MESSAGE_CORRECT)]

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