#!/usr/bin/env python3

# SàT plugin for XEP-0376
# Copyright (C) 2009-2021 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, Tuple, Optional, Any
from zope.interface import implementer
from twisted.words.protocols.jabber import jid
from twisted.words.protocols.jabber.xmlstream import XMPPHandler
from wokkel import disco, iwokkel, pubsub, data_form
from libervia.backend.core.i18n import _
from libervia.backend.core.constants import Const as C
from libervia.backend.core import exceptions
from libervia.backend.core.xmpp import SatXMPPEntity
from libervia.backend.core.log import getLogger

log = getLogger(__name__)

PLUGIN_INFO = {
    C.PI_NAME: "Pubsub Account Management",
    C.PI_IMPORT_NAME: "XEP-0376",
    C.PI_TYPE: C.PLUG_TYPE_XEP,
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0376"],
    C.PI_DEPENDENCIES: ["XEP-0060"],
    C.PI_MAIN: "XEP_0376",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Pubsub Account Management"""),
}

NS_PAM = "urn:xmpp:pam:0"


class XEP_0376:

    def __init__(self, host):
        log.info(_("Pubsub Account Management initialization"))
        self.host = host
        host.register_namespace("pam", NS_PAM)
        self._p = self.host.plugins["XEP-0060"]
        host.trigger.add("XEP-0060_subscribe", self.subscribe)
        host.trigger.add("XEP-0060_unsubscribe", self.unsubscribe)
        host.trigger.add("XEP-0060_subscriptions", self.subscriptions)

    def get_handler(self, client):
        return XEP_0376_Handler()

    async def profile_connected(self, client):
        if not self.host.hasFeature(client, NS_PAM):
            log.warning(
                "Your server doesn't support Pubsub Account Management, this is used to "
                "track all your subscriptions. You may ask your server administrator to "
                "install it."
            )

    async def _sub_request(
        self,
        client: SatXMPPEntity,
        service: jid.JID,
        nodeIdentifier: str,
        sub_jid: Optional[jid.JID],
        options: Optional[dict],
        subscribe: bool
    ) -> None:
        if sub_jid is None:
            sub_jid = client.jid.userhostJID()
        iq_elt = client.IQ()
        pam_elt = iq_elt.addElement((NS_PAM, "pam"))
        pam_elt["jid"] = service.full()
        subscribe_elt = pam_elt.addElement(
            (pubsub.NS_PUBSUB, "subscribe" if subscribe else "unsubscribe")
        )
        subscribe_elt["node"] = nodeIdentifier
        subscribe_elt["jid"] = sub_jid.full()
        if options:
            options_elt = pam_elt.addElement((pubsub.NS_PUBSUB, "options"))
            options_elt["node"] = nodeIdentifier
            options_elt["jid"] = sub_jid.full()
            form = data_form.Form(
                formType='submit',
                formNamespace=pubsub.NS_PUBSUB_SUBSCRIBE_OPTIONS
            )
            form.makeFields(options)
            options_elt.addChild(form.toElement())

        await iq_elt.send(client.server_jid.full())

    async def subscribe(
        self,
        client: SatXMPPEntity,
        service: jid.JID,
        nodeIdentifier: str,
        sub_jid: Optional[jid.JID] = None,
        options: Optional[dict] = None
    ) -> Tuple[bool, Optional[pubsub.Subscription]]:
        if not self.host.hasFeature(client, NS_PAM) or client.is_component:
            return True, None

        await self._sub_request(client, service, nodeIdentifier, sub_jid, options, True)

        # TODO: actual result is sent with <message> stanza, we have to get and use them
        # to known the actual result. XEP-0376 returns an empty <iq> result, thus we don't
        # know here is the subscription actually succeeded

        sub_id = None
        sub = pubsub.Subscription(nodeIdentifier, sub_jid, "subscribed", options, sub_id)
        return False, sub

    async def unsubscribe(
        self,
        client: SatXMPPEntity,
        service: jid.JID,
        nodeIdentifier: str,
        sub_jid: Optional[jid.JID],
        subscriptionIdentifier: Optional[str],
        sender: Optional[jid.JID] = None,
    ) -> bool:
        if not self.host.hasFeature(client, NS_PAM) or client.is_component:
            return True
        await self._sub_request(client, service, nodeIdentifier, sub_jid, None, False)
        return False

    async def subscriptions(
        self,
        client: SatXMPPEntity,
        service: Optional[jid.JID],
        node: str,
    ) -> Tuple[bool, Optional[List[Dict[str, Any]]]]:
        if not self.host.hasFeature(client, NS_PAM):
            return True, None
        if service is not None or node is not None:
            # if we have service and/or node subscriptions, it's a regular XEP-0060
            # subscriptions request
            return True, None

        iq_elt = client.IQ("get")
        subscriptions_elt = iq_elt.addElement((NS_PAM, "subscriptions"))
        result_elt = await iq_elt.send()
        try:
            subscriptions_elt = next(result_elt.elements(NS_PAM, "subscriptions"))
        except StopIteration:
            raise ValueError(f"invalid PAM response: {result_elt.toXml()}")
        subs = []
        for subscription_elt in subscriptions_elt.elements(NS_PAM, "subscription"):
            sub = {}
            try:
                for attr, key in (
                    ("service", "service"),
                    ("node", "node"),
                    ("jid", "subscriber"),
                    ("subscription", "state")
                ):
                    sub[key] = subscription_elt[attr]
            except KeyError as e:
                log.warning(
                    f"Invalid <subscription> element (missing {e.args[0]!r} attribute): "
                    f"{subscription_elt.toXml()}"
                )
                continue
            sub_id = subscription_elt.getAttribute("subid")
            if sub_id:
                sub["id"] = sub_id
            subs.append(sub)

        return False, subs


@implementer(iwokkel.IDisco)
class XEP_0376_Handler(XMPPHandler):

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

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