#!/usr/bin/env python3

# Libervia plugin
# 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 typing import Dict, List, Optional, Union

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 import exceptions
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_RTP_HDREXT = "urn:xmpp:jingle:apps:rtp:rtp-hdrext:0"

PLUGIN_INFO = {
    C.PI_NAME: "Jingle RTP Header Extensions Negotiation",
    C.PI_IMPORT_NAME: "XEP-0294",
    C.PI_TYPE: "XEP",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0294"],
    C.PI_DEPENDENCIES: ["XEP-0167"],
    C.PI_RECOMMENDATIONS: [],
    C.PI_MAIN: "XEP_0294",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Jingle RTP Header Extensions Negotiation"""),
}


class XEP_0294:
    def __init__(self, host):
        log.info(f"plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization")
        host.trigger.add("XEP-0167_parse_sdp_a", self._parse_sdp_a_trigger)
        host.trigger.add(
            "XEP-0167_generate_sdp_content", self._generate_sdp_content_trigger
        )
        host.trigger.add("XEP-0167_parse_description", self._parse_description_trigger)
        host.trigger.add("XEP-0167_build_description", self._build_description_trigger)

    def get_handler(self, client):
        return XEP_0294_handler()

    def _parse_extmap(self, parts: List[str], application_data: dict) -> None:
        """Parse an individual extmap line and fill application_data accordingly"""
        if "/" in parts[0]:
            id_, direction = parts[0].split("/", 1)
        else:
            id_ = parts[0]
            direction = None
        uri = parts[1]
        attributes = parts[2:]

        if direction in (None, "sendrecv"):
            senders = "both"
        elif direction == "sendonly":
            senders = "initiator"
        elif direction == "recvonly":
            senders = "responder"
        elif direction == "inactive":
            senders = "none"
        else:
            log.warning(f"invalid direction for extmap: {direction}")
            senders = "sendrecv"

        rtp_hdr_ext_data: Dict[str, Union[str, dict]] = {
            "id": id_,
            "uri": uri,
            "senders": senders,
        }

        if attributes:
            parameters = {}
            for attribute in attributes:
                name, *value = attribute.split("=", 1)
                parameters[name] = value[0] if value else None
            rtp_hdr_ext_data["parameters"] = parameters

        application_data.setdefault("rtp-hdrext", {})[id_] = rtp_hdr_ext_data

    def _parse_sdp_a_trigger(
        self,
        attribute: str,
        parts: List[str],
        call_data: dict,
        metadata: dict,
        media_type: str,
        application_data: Optional[dict],
        transport_data: dict,
    ) -> None:
        """Parse "extmap" and "extmap-allow-mixed" attributes"""
        if attribute == "extmap":
            if application_data is None:
                call_data.setdefault("_extmaps", []).append(parts)
            else:
                self._parse_extmap(parts, application_data)
        elif attribute == "extmap-allow-mixed":
            if application_data is None:
                call_data["_extmap-allow-mixed"] = True
            else:
                application_data["extmap-allow-mixed"] = True
        elif (
            application_data is not None
            and "_extmaps" in call_data
            and "rtp-hdrext" not in application_data
        ):
            extmaps = call_data.pop("_extmaps")
            for parts in extmaps:
                self._parse_extmap(parts, application_data)
        elif (
            application_data is not None
            and "_extmap-allow-mixed" in call_data
            and "extmap-allow-mixed" not in application_data
        ):
            value = call_data.pop("_extmap-allow-mixed")
            application_data["extmap-allow-mixed"] = value

    def _generate_sdp_content_trigger(
        self,
        session: dict,
        local: bool,
        idx: int,
        content_data: dict,
        sdp_lines: List[str],
        application_data: dict,
        app_data_key: str,
        media_data: dict,
        media: str,
    ) -> None:
        """Generate "extmap" and "extmap-allow-mixed" attributes"""
        rtp_hdrext_dict = media_data.get("rtp-hdrext", {})

        for id_, ext_data in rtp_hdrext_dict.items():
            senders = ext_data.get("senders")
            if senders in (None, "both"):
                direction = "sendrecv"
            elif senders == "initiator":
                direction = "sendonly"
            elif senders == "responder":
                direction = "recvonly"
            elif senders == "none":
                direction = "inactive"
            else:
                raise exceptions.InternalError(
                    f"Invalid senders value for extmap: {ext_data.get('senders')}"
                )

            parameters_str = ""
            if "parameters" in ext_data:
                parameters_str = " " + " ".join(
                    f"{k}={v}" if v is not None else f"{k}"
                    for k, v in ext_data["parameters"].items()
                )

            sdp_lines.append(
                f"a=extmap:{id_}/{direction} {ext_data['uri']}{parameters_str}"
            )

        if media_data.get("extmap-allow-mixed", False):
            sdp_lines.append("a=extmap-allow-mixed")

    def _parse_description_trigger(
        self, desc_elt: domish.Element, media_data: dict
    ) -> None:
        """Parse the <rtp-hdrext> and <extmap-allow-mixed> elements"""
        for rtp_hdrext_elt in desc_elt.elements(NS_JINGLE_RTP_HDREXT, "rtp-hdrext"):
            id_ = rtp_hdrext_elt["id"]
            uri = rtp_hdrext_elt["uri"]
            senders = rtp_hdrext_elt.getAttribute("senders", "both")
            # FIXME: workaround for Movim bug https://github.com/movim/movim/issues/1212
            if senders in ("sendonly", "recvonly", "sendrecv", "inactive"):
                log.warning("Movim bug workaround for wrong extmap value")
                if senders == "sendonly":
                    senders = "initiator"
                elif senders == "recvonly":
                    senders = "responder"
                elif senders == "sendrecv":
                    senders = "both"
                else:
                    senders = "none"

            media_data.setdefault("rtp-hdrext", {})[id_] = {
                "id": id_,
                "uri": uri,
                "senders": senders,
            }

            parameters = {}
            for param_elt in rtp_hdrext_elt.elements(NS_JINGLE_RTP_HDREXT, "parameter"):
                try:
                    parameters[param_elt["name"]] = param_elt.getAttribute("value")
                except KeyError:
                    log.warning(f"invalid parameters (missing name): {param_elt.toXml()}")

            if parameters:
                media_data["rtp-hdrext"][id_]["parameters"] = parameters

        try:
            next(desc_elt.elements(NS_JINGLE_RTP_HDREXT, "extmap-allow-mixed"))
        except StopIteration:
            pass
        else:
            media_data["extmap-allow-mixed"] = True

    def _build_description_trigger(
        self, desc_elt: domish.Element, media_data: dict, session: dict
    ) -> None:
        """Build the <rtp-hdrext> and <extmap-allow-mixed> elements if possible"""
        for id_, hdrext_data in media_data.get("rtp-hdrext", {}).items():
            rtp_hdrext_elt = desc_elt.addElement((NS_JINGLE_RTP_HDREXT, "rtp-hdrext"))
            rtp_hdrext_elt["id"] = id_
            rtp_hdrext_elt["uri"] = hdrext_data["uri"]
            senders = hdrext_data.get("senders", "both")
            if senders != "both":
                # we must not set "both" senders otherwise calls will fail with Movim due
                # to https://github.com/movim/movim/issues/1213
                rtp_hdrext_elt["senders"] = senders

            for name, value in hdrext_data.get("parameters", {}).items():
                param_elt = rtp_hdrext_elt.addElement((NS_JINGLE_RTP_HDREXT, "parameter"))
                param_elt["name"] = name
                if value is not None:
                    param_elt["value"] = value

        if media_data.get("extmap-allow-mixed", False):
            desc_elt.addElement((NS_JINGLE_RTP_HDREXT, "extmap-allow-mixed"))


@implementer(itx_xmpp.IDisco)
class XEP_0294_handler(XMPPHandler):
    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
        return [disco.DiscoFeature(NS_JINGLE_RTP_HDREXT)]

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