#!/usr/bin/env python3

# Libervia plugin to handle Audio/Video conferences
# Copyright (C) 2009-2026 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 twisted.words.protocols.jabber.xmlstream import XMPPHandler
from twisted.words.xish import domish
from tx_xmpp import disco, itx_xmpp
from zope.interface import implementer

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.plugins.plugin_xep_0166 import XEP_0166

log = getLogger(__name__)


PLUGIN_INFO = {
    C.PI_NAME: "Jingle A/V Conferences",
    C.PI_IMPORT_NAME: "AV_CONFERENCES",
    C.PI_TYPE: "MISC",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: [],
    C.PI_DEPENDENCIES: ["XEP-0166", "XEP-0167"],
    C.PI_MAIN: "AVConferences",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _(
        "Handle Audio/Video conferences (A/V calls with a large number of participants).\n"
        "This plugin implements the Jingle Audio/Video conferences for calls with a "
        "large number of participants."
    ),
}

NS_AV_CONFERENCES = "urn:xmpp:jingle:av-conferences:0"


class AVConferences:
    namespace = NS_AV_CONFERENCES

    def __init__(self, host):
        log.info(f"plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization")
        self.host = host
        self._j: XEP_0166 = host.plugins["XEP-0166"]
        host.trigger.add("XEP-0167_jingle_handler", self._jingle_handler_trigger)

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

    def _jingle_handler_trigger(
        self,
        client: SatXMPPEntity,
        action: str,
        session: dict,
        content_name: str,
        desc_elt: domish.Element,
    ) -> None:
        """Store the origin of the contents.

        The origin is kept in the content's application data, so that it can be exposed to
            the frontend.
        """
        if action != self._j.A_CONTENT_ADD:
            return
        # get <origin> from the element tree, not the session state, which may be updated
        # by a concurrent content-add before this trigger runs
        try:
            jingle_elt = desc_elt.parent.parent
        except AttributeError:
            jingle_elt = None
        if jingle_elt is None:
            jingle_elt = session.get("jingle_elt")
        if jingle_elt is None:
            return
        assert jingle_elt.name == "jingle"
        origin = self.parse_origin(jingle_elt)
        if origin is None:
            return
        log.debug(
            f"Content {content_name!r} of session {session['id']!r} "
            f"({client.jid.full()}) originates from {origin!r}."
        )
        content_data = session["contents"].get(content_name)
        if content_data is not None:
            content_data["application_data"]["origin"] = origin

    @staticmethod
    def build_origin_elt(origin: str) -> domish.Element:
        """Create an <origin> element to identify the stream origin

        @param origin: entity URI of the stream origin (typically an "xmpp:" URL)
        @return: <origin> element
        """
        origin_elt = domish.Element((NS_AV_CONFERENCES, "origin"))
        origin_elt["entity"] = origin
        return origin_elt

    @staticmethod
    def parse_origin(jingle_elt: domish.Element) -> str | None:
        """Get the origin of the stream from a <jingle> element

        @return: entity URI of the stream origin, or None
        """
        try:
            origin_elt = next(jingle_elt.elements(NS_AV_CONFERENCES, "origin"))
        except StopIteration:
            return None
        return origin_elt.getAttribute("entity")


@implementer(itx_xmpp.IDisco)
class AVConferencesHandler(XMPPHandler):
    def __init__(self, plugin_parent):
        self.plugin_parent = plugin_parent

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

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