-- Bidirectional Server-to-Server Connections

-- http://xmpp.org/extensions/xep-0288.html

-- Copyright (C) 2013 Kim Alvefur

--

-- This file is MIT/X11 licensed.

--

local s2smanager = require"core.s2smanager";

local add_filter = require "util.filters".add_filter;

local st = require "util.stanza";

local jid_split = require"util.jid".prepped_split;

local xmlns_bidi_feature = "urn:xmpp:features:bidi"

local xmlns_bidi = "urn:xmpp:bidi";

local noop = function () end

local traceback = debug.traceback;

local function handleerr(err) log("error", "Traceback[s2s]: %s: %s", tostring(err), traceback()); end

local function handlestanza(session, stanza)

	if stanza.attr.xmlns == "jabber:client" then --COMPAT: Prosody pre-0.6.2 may send jabber:client

		stanza.attr.xmlns = nil;

	end

	-- stanza = session.filter("stanzas/in", stanza);

	if stanza then

		return xpcall(function () return core_process_stanza(session, stanza) end, handleerr);

	end

end

local function new_bidi(origin)

	local bidi_session, remote_host;

	origin.log("debug", "Creating bidirectional session wrapper");

	if origin.direction == "incoming" then -- then we create an "outgoing" bidirectional session

		local conflicting_session = hosts[origin.to_host].s2sout[origin.from_host]

		if conflicting_session then

			conflicting_session.log("info", "We already have an outgoing connection to %s, closing it...", origin.from_host);

			conflicting_session:close{ condition = "conflict", text = "Replaced by bidirectional stream" }

			s2smanager.destroy_session(conflicting_session);

		end

		remote_host = origin.from_host;

		bidi_session = s2smanager.new_outgoing(origin.to_host, origin.from_host)

	else -- outgoing -- then we create an "incoming" bidirectional session

		remote_host = origin.to_host;

		bidi_session = s2smanager.new_incoming(origin.conn)

		bidi_session.to_host = origin.from_host;

		bidi_session.from_host = origin.to_host;

		add_filter(origin, "stanzas/in", function(stanza)

			if stanza.attr.xmlns ~= nil then return stanza end

			local _, host = jid_split(stanza.attr.from);

			if host ~= remote_host then return stanza end

			handlestanza(bidi_session, stanza);

		end, 1);

	end

	origin.bidi_session = bidi_session;

	bidi_session.sends2s = origin.sends2s;

	bidi_session.bounce_sendq = noop;

	bidi_session.notopen = nil;

	bidi_session.is_bidi = true;

	bidi_session.bidi_session = false;

	bidi_session.orig_session = origin;

	bidi_session.secure = origin.secure;

	bidi_session.cert_identity_status = origin.cert_identity_status;

	bidi_session.cert_chain_status = origin.cert_chain_status;

	bidi_session.close = function(...)

		return origin.close(...);

	end

	bidi_session.log("info", "Bidirectional session established");

	s2smanager.make_authenticated(bidi_session, remote_host);

	return bidi_session;

end

-- Incoming s2s

module:hook("s2s-stream-features", function(event)

	local origin, features = event.origin, event.features;

	if not origin.is_bidi and not hosts[module.host].s2sout[origin.from_host] then

		module:log("debug", "Announcing support for bidirectional streams");

		features:tag("bidi", { xmlns = xmlns_bidi_feature }):up();

	end

end);

module:hook("stanza/urn:xmpp:bidi:bidi", function(event)

	local origin = event.session or event.origin;

	if not origin.is_bidi and not origin.bidi_session then

		module:log("debug", "%s requested bidirectional stream", origin.from_host);

		origin.do_bidi = true;

		return true;

	end

end);

-- Outgoing s2s

module:hook("stanza/http://etherx.jabber.org/streams:features", function(event)

	local origin = event.session or event.origin;

	if not ( origin.bidi_session or origin.is_bidi or origin.do_bidi)

	and event.stanza:get_child("bidi", xmlns_bidi_feature) then

		module:log("debug", "%s supports bidirectional streams", origin.to_host);

		origin.sends2s(st.stanza("bidi", { xmlns = xmlns_bidi }));

		origin.do_bidi = true;

	end

end, 160);

function enable_bidi(event)

	local session = event.session;

	if session.do_bidi and not ( session.is_bidi or session.bidi_session ) then

		session.do_bidi = nil;

		new_bidi(session);

	end

end

module:hook("s2sin-established", enable_bidi);

module:hook("s2sout-established", enable_bidi);

function disable_bidi(event)

	local session = event.session;

	if session.bidi_session then

		local bidi_session = session.bidi_session;

		session.bidi_session, bidi_session.orig_session = nil, nil;

		session.log("debug", "Tearing down bidirectional stream");

		s2smanager.destroy_session(bidi_session, event.reason);

	elseif session.orig_session then

		local orig_session = session.orig_session;

		orig_session.bidi_session, session.orig_session = nil, nil;

		orig_session.log("debug", "Tearing down bidirectional stream");

		s2smanager.destroy_session(orig_session, event.reason);

	end

end

module:hook("s2sin-destroyed", disable_bidi);

module:hook("s2sout-destroyed", disable_bidi);