#!/usr/bin/env python3

# 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 collections.abc import Iterator
from typing import Any, Final, Self

from pydantic import BaseModel, Field, RootModel
from twisted.internet import defer
from twisted.words.protocols.jabber import xmlstream
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.core_types import SatXMPPEntity
from libervia.backend.core.i18n import _
from libervia.backend.core.log import getLogger

log = getLogger(__name__)

EXTRA_KEY: Final = "oob"


PLUGIN_INFO = {
    C.PI_NAME: "Out of Band Data",
    C.PI_IMPORT_NAME: "XEP-0066",
    C.PI_TYPE: "XEP",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0066"],
    C.PI_MAIN: "XEP_0066",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation of XEP-0066 (Out of Band Data)"""),
}

NS_OOB = "jabber:x:oob"


class OOB(BaseModel):
    """OOB data"""

    url: str = Field(description="URI of the resource.")
    desc: str | None = Field(
        default=None,
        description="Description of the resource.",
    )

    def to_element(self) -> domish.Element:
        """Build the ``<x>`` element from this instance's data.

        @return: <x> OOB element.
        """
        x_elt = domish.Element((NS_OOB, "x"))
        url_elt = x_elt.addElement("url")
        url_elt.addContent(self.url)
        if self.desc is not None:
            desc_elt = x_elt.addElement("desc")
            desc_elt.addContent(self.desc)
        return x_elt

    @classmethod
    def from_element(cls, element: domish.Element) -> Self:
        """Create an OOB instance from an <x> element.

        @param element: <x> OOB element.
        @return: OOB instance.
        @raise exceptions.DataError: The <url> element is missing.
        """
        url_elt = next(element.elements(NS_OOB, "url"), None)
        if url_elt is None:
            raise exceptions.DataError("<url> element is missing")

        desc_elt = next(element.elements(NS_OOB, "desc"), None)
        return cls(url=str(url_elt), desc=str(desc_elt) if desc_elt is not None else None)


class OOBList(RootModel):
    """List of OOB data."""

    root: list[OOB]

    def __iter__(self) -> Iterator[OOB]:  # type: ignore[override]
        return iter(self.root)

    def __getitem__(self, item: int) -> OOB:
        return self.root[item]

    def __len__(self) -> int:
        return len(self.root)

    def append(self, item: OOB) -> None:
        self.root.append(item)

    @classmethod
    def from_element(cls, parent_elt: domish.Element) -> Self:
        """Create an OOBList instance from a parent element.

        @param parent_elt: Parent element containing <x> OOB children.
        @return: OOBList instance.
        """
        return cls([OOB.from_element(elt) for elt in parent_elt.elements(NS_OOB, "x")])


class XEP_0066:

    def __init__(self, host):
        log.info(f"Plugin {PLUGIN_INFO[C.PI_NAME]!r} initialization.")
        host.register_namespace("oob", NS_OOB)
        host.trigger.add("message_received", self._message_received_trigger)

    def generate_oob(self, url: str, desc: str | None = None) -> domish.Element:
        """Generate an OOB element.

        @param url: URI of the resource.
        @param desc: Optional description of the resource.
        @return: ``<x xmlns='jabber:x:oob'>`` element.
        """
        return OOB(url=url, desc=desc).to_element()

    def _message_received_trigger(
        self,
        client: SatXMPPEntity,
        message_elt: domish.Element,
        post_treat: defer.Deferred,
    ) -> bool:
        """Check presence of OOB in message.

        @param client: client instance.
        @param message_elt: the <message/> element.
        @param post_treat: deferred to add post-treatments to.
        @return: True to continue message processing.
        """
        oob_list = OOBList.from_element(message_elt)
        if oob_list:
            post_treat.addCallback(self._add_oob, oob_list)
        return True

    def _add_oob(self, data: dict[str, Any], oob_list: OOBList) -> dict[str, Any]:
        """Add OOB data to message extra.

        @param data: message data dict.
        @param oob_list: parsed OOB list.
        @return: updated message data dict.
        """
        data["extra"][EXTRA_KEY] = oob_list.model_dump()
        return data

    def get_handler(self, client: SatXMPPEntity) -> "XEP_0066Handler":
        return XEP_0066Handler()


@implementer(itx_xmpp.IDisco)
class XEP_0066Handler(xmlstream.XMPPHandler):

    def getDiscoInfo(self, requestor: str, target: str, nodeIdentifier: str = "") -> list:
        return [disco.DiscoFeature(NS_OOB)]

    def getDiscoItems(
        self, requestor: str, target: str, nodeIdentifier: str = ""
    ) -> list:
        return []