#!/usr/bin/env python3


# SAT plugin for managing pipes (experimental)
# 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/>.

import errno
from zope import interface
from twisted.words.xish import domish
from twisted.words.protocols.jabber import jid
from twisted.internet import defer
from twisted.internet import protocol
from twisted.internet import endpoints
from twisted.internet import reactor
from twisted.internet import error
from twisted.internet import interfaces
from libervia.backend.core.i18n import _, D_
from libervia.backend.core.constants import Const as C
from libervia.backend.core import exceptions
from libervia.backend.core.log import getLogger
from libervia.backend.tools import xml_tools
from libervia.backend.tools import stream


log = getLogger(__name__)

NS_STREAM = "http://salut-a-toi.org/protocol/stream"
SECURITY_LIMIT = 30
START_PORT = 8888

PLUGIN_INFO = {
    C.PI_NAME: "Jingle Stream Plugin",
    C.PI_IMPORT_NAME: "STREAM",
    C.PI_TYPE: "EXP",
    C.PI_PROTOCOLS: [],
    C.PI_DEPENDENCIES: ["XEP-0166"],
    C.PI_MAIN: "JingleStream",
    C.PI_HANDLER: "no",
    C.PI_DESCRIPTION: _("""Jingle Stream plugin"""),
}

CONFIRM = D_("{peer} wants to send you a stream, do you accept ?")
CONFIRM_TITLE = D_("Stream Request")


class StreamProtocol(protocol.Protocol):
    def __init__(self):
        self.pause = False

    def set_pause(self, paused):
        # in Python 2.x, Twisted classes are old style
        # so we can use property and setter
        if paused:
            if not self.pause:
                self.transport.pauseProducing()
                self.pause = True
        else:
            if self.pause:
                self.transport.resumeProducing()
                self.pause = False

    def disconnect(self):
        self.transport.loseConnection()

    def connectionMade(self):
        if self.factory.client_conn is not None:
            self.transport.loseConnection()
        self.factory.set_client_conn(self)

    def dataReceived(self, data):
        self.factory.write_to_consumer(data)

    def sendData(self, data):
        self.transport.write(data)

    def connectionLost(self, reason):
        if self.factory.client_conn != self:
            # only the first connected client_conn is relevant
            return

        if reason.type == error.ConnectionDone:
            self.factory.stream_finished()
        else:
            self.factory.stream_failed(reason)


@interface.implementer(stream.IStreamProducer)
@interface.implementer(interfaces.IPushProducer)
@interface.implementer(interfaces.IConsumer)
class StreamFactory(protocol.Factory):
    protocol = StreamProtocol
    consumer = None
    producer = None
    deferred = None

    def __init__(self):
        self.client_conn = None

    def set_client_conn(self, stream_protocol):
        # in Python 2.x, Twisted classes are old style
        # so we can use property and setter
        assert self.client_conn is None
        self.client_conn = stream_protocol
        if self.consumer is None:
            self.client_conn.set_pause(True)

    def start_stream(self, consumer):
        if self.consumer is not None:
            raise exceptions.InternalError(
                _("stream can't be used with multiple consumers")
            )
        assert self.deferred is None
        self.consumer = consumer
        consumer.registerProducer(self, True)
        self.deferred = defer.Deferred()
        if self.client_conn is not None:
            self.client_conn.set_pause(False)
        return self.deferred

    def stream_finished(self):
        self.client_conn = None
        if self.consumer:
            self.consumer.unregisterProducer()
            self.port_listening.stopListening()
        self.deferred.callback(None)

    def stream_failed(self, failure_):
        self.client_conn = None
        if self.consumer:
            self.consumer.unregisterProducer()
            self.port_listening.stopListening()
            self.deferred.errback(failure_)
        elif self.producer:
            self.producer.stopProducing()

    def stop_stream(self):
        if self.client_conn is not None:
            self.client_conn.disconnect()

    def registerProducer(self, producer, streaming):
        self.producer = producer

    def pauseProducing(self):
        self.client_conn.set_pause(True)

    def resumeProducing(self):
        self.client_conn.set_pause(False)

    def stopProducing(self):
        if self.client_conn:
            self.client_conn.disconnect()

    def write(self, data):
        try:
            self.client_conn.sendData(data)
        except AttributeError:
            log.warning(_("No client connected, can't send data"))

    def write_to_consumer(self, data):
        self.consumer.write(data)


class JingleStream(object):
    """This non standard jingle application send byte stream"""

    def __init__(self, host):
        log.info(_("Plugin Stream initialization"))
        self.host = host
        self._j = host.plugins["XEP-0166"]  # shortcut to access jingle
        self._j.register_application(NS_STREAM, self)
        host.bridge.add_method(
            "stream_out",
            ".plugin",
            in_sign="ss",
            out_sign="s",
            method=self._stream_out,
            async_=True,
        )

    # jingle callbacks

    def _stream_out(self, to_jid_s, profile_key):
        client = self.host.get_client(profile_key)
        return defer.ensureDeferred(self.stream_out(client, jid.JID(to_jid_s)))

    async def stream_out(self, client, to_jid):
        """send a stream

        @param peer_jid(jid.JID): recipient
        @return: an unique id to identify the transfer
        """
        port = START_PORT
        factory = StreamFactory()
        while True:
            endpoint = endpoints.TCP4ServerEndpoint(reactor, port)
            try:
                port_listening = await endpoint.listen(factory)
            except error.CannotListenError as e:
                if e.socketError.errno == errno.EADDRINUSE:
                    port += 1
                else:
                    raise e
            else:
                factory.port_listening = port_listening
                break
        # we don't want to wait for IQ result of initiate
        defer.ensureDeferred(self._j.initiate(
            client,
            to_jid,
            [
                {
                    "app_ns": NS_STREAM,
                    "senders": self._j.ROLE_INITIATOR,
                    "app_kwargs": {"stream_object": factory},
                }
            ],
        ))
        return str(port)

    def jingle_session_init(self, client, session, content_name, stream_object):
        content_data = session["contents"][content_name]
        application_data = content_data["application_data"]
        assert "stream_object" not in application_data
        application_data["stream_object"] = stream_object
        desc_elt = domish.Element((NS_STREAM, "description"))
        return desc_elt

    @defer.inlineCallbacks
    def jingle_request_confirmation(self, client, action, session, content_name, desc_elt):
        """This method request confirmation for a jingle session"""
        content_data = session["contents"][content_name]
        if content_data["senders"] not in (
            self._j.ROLE_INITIATOR,
            self._j.ROLE_RESPONDER,
        ):
            log.warning("Bad sender, assuming initiator")
            content_data["senders"] = self._j.ROLE_INITIATOR

        confirm_data = yield xml_tools.defer_dialog(
            self.host,
            _(CONFIRM).format(peer=session["peer_jid"].full()),
            _(CONFIRM_TITLE),
            type_=C.XMLUI_DIALOG_CONFIRM,
            action_extra={
                "from_jid": session["peer_jid"].full(),
                "type": "STREAM",
            },
            security_limit=SECURITY_LIMIT,
            profile=client.profile,
        )

        if not C.bool(confirm_data["answer"]):
            defer.returnValue(False)
        try:
            port = int(confirm_data["port"])
        except (ValueError, KeyError):
            raise exceptions.DataError(_("given port is invalid"))
        endpoint = endpoints.TCP4ClientEndpoint(reactor, "localhost", port)
        factory = StreamFactory()
        yield endpoint.connect(factory)
        content_data["stream_object"] = factory
        finished_d = content_data["finished_d"] = defer.Deferred()
        args = [client, session, content_name, content_data]
        finished_d.addCallbacks(self._finished_cb, self._finished_eb, args, None, args)
        defer.returnValue(True)

    def jingle_handler(self, client, action, session, content_name, desc_elt):
        content_data = session["contents"][content_name]
        application_data = content_data["application_data"]
        if action in (self._j.A_ACCEPTED_ACK, self._j.A_SESSION_INITIATE):
            pass
        elif action == self._j.A_SESSION_ACCEPT:
            assert not "stream_object" in content_data
            content_data["stream_object"] = application_data["stream_object"]
            finished_d = content_data["finished_d"] = defer.Deferred()
            args = [client, session, content_name, content_data]
            finished_d.addCallbacks(self._finished_cb, self._finished_eb, args, None, args)
        else:
            log.warning("FIXME: unmanaged action {}".format(action))
        return desc_elt

    def _finished_cb(self, __, client, session, content_name, content_data):
        log.info("Pipe transfer completed")
        self._j.content_terminate(client, session, content_name)
        content_data["stream_object"].stop_stream()

    def _finished_eb(self, failure, client, session, content_name, content_data):
        log.warning("Error while streaming pipe: {}".format(failure))
        self._j.content_terminate(
            client, session, content_name, reason=self._j.REASON_FAILED_TRANSPORT
        )
        content_data["stream_object"].stop_stream()