#!/usr/bin/env python3

# Copyright (C) 2009-2022 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 Optional, List, Tuple, Union, NamedTuple
from collections import namedtuple

from twisted.words.protocols.jabber import xmlstream
from twisted.words.xish import domish
from wokkel import disco
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
from libervia.backend.core.core_types import SatXMPPEntity
from libervia.backend.memory.sqla_mapping import History
from libervia.backend.tools.common.async_utils import async_lru

log = getLogger(__name__)


PLUGIN_INFO = {
    C.PI_NAME: "Message Fastening",
    C.PI_IMPORT_NAME: "XEP-0422",
    C.PI_TYPE: "XEP",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0359", "XEP-0422"],
    C.PI_MAIN: "XEP_0422",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation Message Fastening"""),
}

NS_FASTEN = "urn:xmpp:fasten:0"


class FastenMetadata(NamedTuple):
    elements: List[domish.Element]
    id: str
    history: Optional[History]
    clear: bool
    shell: bool


class XEP_0422(object):

    def __init__(self, host):
        log.info(_("XEP-0422 (Message Fastening) plugin initialization"))
        self.host = host
        host.register_namespace("fasten", NS_FASTEN)

    def get_handler(self, __):
        return XEP_0422_handler()

    def apply_to_elt(
        self,
        message_elt: domish.Element,
        origin_id: str,
        clear: Optional[bool] = None,
        shell: Optional[bool] = None,
        children: Optional[List[domish.Element]] = None,
        external: Optional[List[Union[str, Tuple[str, str]]]] = None
    ) -> domish.Element:
        """Generate, add and return <apply-to> element

        @param message_elt: wrapping <message> element
        @param origin_id: origin ID of the target message
        @param clear: set to True to remove a fastening
        @param shell: set to True when using e2ee shell
            cf. https://xmpp.org/extensions/xep-0422.html#encryption
        @param children: element to fasten to the target message
            <apply-to> element is returned, thus children can also easily be added
            afterwards
        @param external: <external> element to add
            cf. https://xmpp.org/extensions/xep-0422.html#external-payloads
            the list items can either be a str with only the element name,
            or a tuple which must then be (namespace, name)
        @return: <apply-to> element, which is already added to the wrapping message_elt
        """
        apply_to_elt = message_elt.addElement((NS_FASTEN, "apply-to"))
        apply_to_elt["id"] = origin_id
        if clear is not None:
            apply_to_elt["clear"] = C.bool_const(clear)
        if shell is not None:
            apply_to_elt["shell"] = C.bool_const(shell)
        if children is not None:
            for child in children:
                apply_to_elt.addChild(child)
        if external is not None:
            for ext in external:
                external_elt = apply_to_elt.addElement("external")
                if isinstance(ext, str):
                    external_elt["name"] = ext
                else:
                    ns, name = ext
                    external_elt["name"] = name
                    external_elt["element-namespace"] = ns
        return apply_to_elt

    @async_lru(maxsize=5)
    async def get_fastened_elts(
        self,
        client: SatXMPPEntity,
        message_elt: domish.Element
    ) -> Optional[FastenMetadata]:
        """Get fastened elements

        if the message contains no <apply-to> element, None is returned
        """
        try:
            apply_to_elt = next(message_elt.elements(NS_FASTEN, "apply-to"))
        except StopIteration:
            return None
        else:
            origin_id = apply_to_elt.getAttribute("id")
            if not origin_id:
                log.warning(
                    f"Received invalid fastening message: {message_elt.toXml()}"
                )
                return None
            elements = apply_to_elt.children
            if not elements:
                log.warning(f"No element to fasten: {message_elt.toXml()}")
                return None
            history = await self.host.memory.storage.get(
                client,
                History,
                History.origin_id,
                origin_id,
                (History.messages, History.subjects, History.thread)
            )
            return FastenMetadata(
                elements,
                origin_id,
                history,
                C.bool(apply_to_elt.getAttribute("clear", C.BOOL_FALSE)),
                C.bool(apply_to_elt.getAttribute("shell", C.BOOL_FALSE)),
            )


@implementer(disco.IDisco)
class XEP_0422_handler(xmlstream.XMPPHandler):

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

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