-- Prosody IM v0.4

-- Copyright (C) 2008-2009 Matthew Wild

-- Copyright (C) 2008-2009 Waqas Hussain

-- 

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

if module:get_host_type() ~= "component" then

	error("Don't load mod_component manually, it should be for a component, please see http://prosody.im/doc/components", 0);

end

local t_concat = table.concat;

local connlisteners = require "net.connlisteners";

local cm_register_component = require "core.componentmanager".register_component;

local uuid_gen = require "util.uuid".generate;

local sha1 = require "util.hashes".sha1;

local st = stanza;

local init_xmlhandlers = require "core.xmlhandlers";

local sessions = {};

local log = module._log;

local component_listener = { default_port = 5347; default_mode = "*a"; };

local xmlns_component = 'jabber:component:accept';

--- Callbacks/data for xmlhandlers to handle streams for us ---

local stream_callbacks = { stream_tag = "http://etherx.jabber.org/streams|stream", default_ns = xmlns_component };

function stream_callbacks.error(session, error, data, data2)

	log("warn", "Error processing component stream: "..tostring(error));

	if error == "no-stream" then

		session:close("invalid-namespace");

	elseif error == "xml-parse-error" and data == "unexpected-element-close" then

		session.log("debug", "Unexpected close of '%s' tag", data2);

		session:close("xml-not-well-formed");

	else

		session.log("debug", "External component %s XML parse error: %s", tostring(session.host), tostring(error));

		print(data, debug.traceback())

		session:close("xml-not-well-formed");

	end

end

function stream_callbacks.streamopened(session, attr)

	if config.get(attr.to, "core", "component_module") ~= "component" then

		-- Trying to act as a component domain which 

		-- hasn't been configured

		session:close{ condition = "host-unknown", text = tostring(attr.to).." does not match any configured external components" };

		return;

	end

	-- Store the original host (this is used for config, etc.)

	session.user = attr.to;

	-- Set the host for future reference

	session.host = config.get(attr.to, "core", "component_address") or attr.to;

	-- Note that we don't create the internal component 

	-- until after the external component auths successfully

	session.streamid = uuid_gen();

	session.notopen = nil;

	session.send(st.stanza("stream:stream", { xmlns=xmlns_component,

			["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.host }):top_tag());

end

function stream_callbacks.streamclosed(session)

end

local core_process_stanza = core_process_stanza;

function stream_callbacks.handlestanza(session, stanza)

	-- Namespaces are icky.

	log("warn", "Handing stanza with name %s", stanza.name);

	if stanza.name ~= "handshake" then

		return core_process_stanza(session, stanza);

	else

		handle_component_auth(session, stanza);

	end

end

--- Handle authentication attempts by components

function handle_component_auth(session, stanza)

	if (not session.host) or #stanza.tags > 0 then

		session:close("not-authorized");

		return;

	end

	local secret = config.get(session.user, "core", "component_secret");

	if not secret then

		log("warn", "Component attempted to identify as %s, but component_password is not set", session.user);

		session:close("not-authorized");

		return;

	end

	local supplied_token = t_concat(stanza);

	local calculated_token = sha1(session.streamid..secret, true);

	if supplied_token:lower() ~= calculated_token:lower() then

		session:close{ condition = "not-authorized", text = "Given token does not match calculated token" };

		return;

	end

	-- Authenticated now

	-- If component not already created for this host, create one now

	if not hosts[session.host].connected then

		local send = session.send;

		session.component_session = cm_register_component(session.host, function (_, data) return send(data); end);

		hosts[session.host].connected = true;

	else

		log("error", "Multiple components bound to the same address, first one wins (TODO: Implement stanza distribution)");

	end

	-- Signal successful authentication

	session.send(st.stanza("handshake"));

end

module:add_handler("component", "handshake", xmlns_component, handle_component_auth);

--[[

-- Helper function to deal with errors processing component stanzas

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

function stream_callbacks.handlestanza(a, b)

	xpcall(function () core_process_stanza(a, b) end, handleerr);

end

]]

--- Closing a component connection

local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};

local function session_close(session, reason)

	local log = session.log or log;

	if session.conn then

		if reason then

			if type(reason) == "string" then -- assume stream error

				log("info", "Disconnecting component, <stream:error> is: %s", reason);

				session.send(st.stanza("stream:error"):tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' }));

			elseif type(reason) == "table" then

				if reason.condition then

					local stanza = st.stanza("stream:error"):tag(reason.condition, stream_xmlns_attr):up();

					if reason.text then

						stanza:tag("text", stream_xmlns_attr):text(reason.text):up();

					end

					if reason.extra then

						stanza:add_child(reason.extra);

					end

					log("info", "Disconnecting component, <stream:error> is: %s", tostring(stanza));

					session.send(stanza);

				elseif reason.name then -- a stanza

					log("info", "Disconnecting component, <stream:error> is: %s", tostring(reason));

					session.send(reason);

				end

			end

		end

		session.send("</stream:stream>");

		session.conn.close();

		component_listener.disconnect(session.conn, "stream error");

	end

end

--- Component connlistener

function component_listener.listener(conn, data)

	local session = sessions[conn];

	if not session then

		local _send = conn.write;

		session = { type = "component", conn = conn, send = function (data) return _send(tostring(data)); end };

		sessions[conn] = session;

		-- Logging functions --

		local conn_name = "xep114-"..tostring(conn):match("[a-f0-9]+$");

		session.log = logger.init(conn_name);

		session.close = session_close;

		session.log("info", "Incoming XEP-0114 connection");

		local parser = lxp.new(init_xmlhandlers(session, stream_callbacks), "|");

		session.parser = parser;

		session.notopen = true;

		function session.data(conn, data)

			local ok, err = parser:parse(data);

			if ok then return; end

			session:close("xml-not-well-formed");

		end

		session.dispatch_stanza = stream_callbacks.handlestanza;

	end

	if data then

		session.data(conn, data);

	end

end

function component_listener.disconnect(conn, err)

	local session = sessions[conn];

	if session then

		(session.log or log)("info", "component disconnected: %s (%s)", tostring(session.host), tostring(err));

		if session.host then

			if session.component then

				deregister_component(session.host);

			end

		end

		sessions[conn]  = nil;

		session = nil;

		collectgarbage("collect");

	end

end

connlisteners.register('component', component_listener);

module:add_event_hook("server-starting", function () connlisteners.start("component"); end);