#!/usr/bin/env python3

# Libervia plugin
# 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/>.

from twisted.words.protocols.jabber.xmlstream import XMPPHandler
from twisted.words.xish import domish
from wokkel import disco, iwokkel
from zope.interface import implementer

from libervia.backend.core.constants import Const as C
from libervia.backend.core.i18n import _
from libervia.backend.core.log import getLogger


log = getLogger(__name__)

NS_JINGLE_DTLS = "urn:xmpp:jingle:apps:dtls:0"

PLUGIN_INFO = {
    C.PI_NAME: "Use of DTLS-SRTP in Jingle Sessions",
    C.PI_IMPORT_NAME: "XEP-0320",
    C.PI_TYPE: "XEP",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0320"],
    C.PI_DEPENDENCIES: ["XEP-0176"],
    C.PI_RECOMMENDATIONS: [],
    C.PI_MAIN: "XEP_0320",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Use of DTLS-SRTP with RTP (for e2ee of A/V calls)"""),
}


class XEP_0320:
    def __init__(self, host):
        log.info(f"plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization")
        host.trigger.add("XEP-0176_parse_transport", self._parse_transport_trigger)
        host.trigger.add("XEP-0176_build_transport", self._build_transport_trigger)

    def get_handler(self, client):
        return XEP_0320_handler()

    def _parse_transport_trigger(
        self, transport_elt: domish.Element, ice_data: dict
    ) -> bool:
        """Parse the <fingerprint> element"""
        fingerprint_elt = next(
            transport_elt.elements(NS_JINGLE_DTLS, "fingerprint"), None
        )
        if fingerprint_elt is not None:
            try:
                ice_data["fingerprint"] = {
                    "hash": fingerprint_elt["hash"],
                    "setup": fingerprint_elt["setup"],
                    "fingerprint": str(fingerprint_elt),
                }
            except KeyError as e:
                log.warning(
                    f"invalid <fingerprint> (attribue {e} is missing): "
                    f"{fingerprint_elt.toXml()})"
                )

        return True

    def _build_transport_trigger(
        self, tranport_elt: domish.Element, ice_data: dict
    ) -> bool:
        """Build the <fingerprint> element if possible"""
        try:
            fingerprint_data = ice_data["fingerprint"]
            hash_ = fingerprint_data["hash"]
            setup = fingerprint_data["setup"]
            fingerprint = fingerprint_data["fingerprint"]
        except KeyError:
            pass
        else:
            fingerprint_elt = tranport_elt.addElement(
                (NS_JINGLE_DTLS, "fingerprint"), content=fingerprint
            )
            fingerprint_elt["hash"] = hash_
            fingerprint_elt["setup"] = setup

        return True


@implementer(iwokkel.IDisco)
class XEP_0320_handler(XMPPHandler):
    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
        return [disco.DiscoFeature(NS_JINGLE_DTLS)]

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