# Copyright (C) 2009 Stephan Erb <steve-e AT h3c.de>
# Copyright (C) 2018 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of Gajim.
#
# Gajim is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published
# by the Free Software Foundation; version 3 only.
#
# Gajim 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Gajim. If not, see <http://www.gnu.org/licenses/>.

# XEP-0115: Entity Capabilities

import weakref
from collections import defaultdict

from nbxmpp.namespaces import Namespace
from nbxmpp.structs import StanzaHandler
from nbxmpp.structs import DiscoIdentity
from nbxmpp.util import compute_caps_hash
from nbxmpp.errors import StanzaError

from gajim.common import app
from gajim.common.const import COMMON_FEATURES
from gajim.common.const import Entity
from gajim.common.helpers import get_optional_features
from gajim.common.nec import NetworkEvent
from gajim.common.task_manager import Task
from gajim.common.modules.base import BaseModule


class Caps(BaseModule):

    _nbxmpp_extends = 'EntityCaps'
    _nbxmpp_methods = [
        'caps',
        'set_caps'
    ]

    def __init__(self, con):
        BaseModule.__init__(self, con)

        self.handlers = [
            StanzaHandler(name='presence',
                          callback=self._entity_caps,
                          ns=Namespace.CAPS,
                          priority=51),
        ]

        self._identities = [
            DiscoIdentity(category='client', type='pc', name='Gajim')
        ]

        self._queued_tasks_by_hash = defaultdict(set)
        self._queued_tasks_by_jid = {}

    def _queue_task(self, task):
        old_task = self._get_task(task.entity.jid)
        if old_task is not None:
            self._remove_task(old_task)

        self._log.info('Queue query for hash %s', task.entity.hash)
        self._queued_tasks_by_hash[task.entity.hash].add(task)
        self._queued_tasks_by_jid[task.entity.jid] = task
        app.task_manager.add_task(task)

    def _get_task(self, jid):
        return self._queued_tasks_by_jid.get(jid)

    def _get_similar_tasks(self, task):
        return self._queued_tasks_by_hash.pop(task.entity.hash)

    def _remove_task(self, task):
        task.set_obsolete()
        del self._queued_tasks_by_jid[task.entity.jid]
        self._queued_tasks_by_hash[task.entity.hash].discard(task)

    def _remove_all_tasks(self):
        for task in self._queued_tasks_by_jid.values():
            task.set_obsolete()
        self._queued_tasks_by_jid.clear()
        self._queued_tasks_by_hash.clear()

    def _entity_caps(self, _con, _stanza, properties):
        if properties.type.is_error or properties.type.is_unavailable:
            return

        if properties.is_self_presence:
            return

        if properties.entity_caps is None:
            return

        task = EntityCapsTask(self._account, properties, self._execute_task)

        self._log.info('Received %s', task.entity)

        disco_info = app.storage.cache.get_caps_entry(task.entity.method,
                                                      task.entity.hash)
        if disco_info is None:
            self._queue_task(task)
            return

        jid = str(properties.jid)
        app.storage.cache.set_last_disco_info(jid, disco_info, cache_only=True)
        app.nec.push_incoming_event(
            NetworkEvent('caps-update',
                         account=self._account,
                         fjid=jid,
                         jid=properties.jid.bare))

    def _execute_task(self, task):
        self._log.info('Request %s from %s', task.entity.hash, task.entity.jid)
        self._con.get_module('Discovery').disco_info(
            task.entity.jid,
            node=f'{task.entity.node}#{task.entity.hash}',
            callback=self._on_disco_info,
            user_data=task.entity.jid)

    def _on_disco_info(self, nbxmpp_task):
        jid = nbxmpp_task.get_user_data()
        task = self._get_task(jid)
        if task is None:
            self._log.info('Task not found for %s', jid)
            return

        self._remove_task(task)

        try:
            disco_info = nbxmpp_task.finish()
        except StanzaError as error:
            self._log.warning(error)
            return

        self._log.info('Disco Info received: %s', disco_info.jid)

        try:
            compute_caps_hash(disco_info)
        except Exception as error:
            self._log.warning('Disco info malformed: %s %s',
                              disco_info.jid, error)
            return

        app.storage.cache.add_caps_entry(
            str(disco_info.jid),
            task.entity.method,
            disco_info.get_caps_hash(),
            disco_info)

        self._log.info('Finished query for %s', task.entity.hash)

        tasks = self._get_similar_tasks(task)

        for task in tasks:
            self._remove_task(task)
            self._log.info('Update %s', task.entity.jid)
            app.nec.push_incoming_event(
                NetworkEvent('caps-update',
                             account=self._account,
                             fjid=str(task.entity.jid),
                             jid=task.entity.jid.bare))

    def update_caps(self):
        if not app.account_is_connected(self._account):
            return

        optional_features = get_optional_features(self._account)
        self.set_caps(self._identities,
                      COMMON_FEATURES + optional_features,
                      'https://gajim.org')

        if not app.account_is_available(self._account):
            return

        app.connections[self._account].change_status(
            app.connections[self._account].status,
            app.connections[self._account].status_message)

    def cleanup(self):
        self._remove_all_tasks()
        BaseModule.cleanup(self)


class EntityCapsTask(Task):
    def __init__(self, account, properties, callback):
        Task.__init__(self)
        self._account = account
        self._callback = weakref.WeakMethod(callback)

        self.entity = Entity(jid=properties.jid,
                             node=properties.entity_caps.node,
                             hash=properties.entity_caps.ver,
                             method=properties.entity_caps.hash)

        self._from_muc = properties.from_muc

    def execute(self):
        callback = self._callback()
        if callback is not None:
            callback(self)

    def preconditions_met(self):
        try:
            client = app.get_client(self._account)
        except Exception:
            return False

        if self._from_muc:
            muc = client.get_module('MUC').get_manager().get(
                self.entity.jid.bare)

            if muc is None or not muc.state.is_joined:
                self.set_obsolete()
                return False

        return client.state.is_available

    def __repr__(self):
        return f'Entity Caps ({self.entity.jid} {self.entity.hash})'

    def __hash__(self):
        return hash(self.entity)


def get_instance(*args, **kwargs):
    return Caps(*args, **kwargs), 'Caps'