--[[

mod_component_client.lua

This module turns Prosody hosts into components of other XMPP servers.

Config:

VirtualHost "component.example.com"

	component_client = {

		host = "localhost";

		port = 5347;

		secret = "hunter2";

	}

]]

local socket = require "socket"

local logger = require "util.logger";

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

local st = require "util.stanza";

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

local new_xmpp_stream = require "util.xmppstream".new;

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

local core_process_stanza = prosody.core_process_stanza;

local hosts = prosody.hosts;

local log = module._log;

local config = module:get_option("component_client", {});

local server_host = config.host or "localhost";

local server_port = config.port or 5347;

local server_secret = config.secret or error("client_component.secret not provided");

local exit_on_disconnect = config.exit_on_disconnect;

local keepalive_interval = config.keepalive_interval or 3600;

local __conn;

local listener = {};

local session;

local xmlns_component = 'jabber:component:accept';

local stream_callbacks = { default_ns = xmlns_component };

local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";

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

	if session.destroyed then return; end

	module:log("warn", "Error processing component stream: %s", tostring(error));

	if error == "no-stream" then

		session:close("invalid-namespace");

	elseif error == "parse-error" then

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

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

	elseif error == "stream-error" then

		local condition, text = "undefined-condition";

		for child in data:children() do

			if child.attr.xmlns == xmlns_xmpp_streams then

				if child.name ~= "text" then

					condition = child.name;

				else

					text = child:get_text();

				end

				if condition ~= "undefined-condition" and text then

					break;

				end

			end

		end

		text = condition .. (text and (" ("..text..")") or "");

		session.log("info", "Session closed by remote with error: %s", text);

		session:close(nil, text);

	end

end

function stream_callbacks.streamopened(session, attr)

	-- TODO check id~=nil, from==module.host

	module:log("debug", "Sending handshake");

	local handshake = st.stanza("handshake"):text(sha1(attr.id..server_secret, true));

	session.send(handshake);

	session.notopen = nil;

end

function stream_callbacks.streamclosed(session)

	session.log("debug", "Received </stream:stream>");

	session:close();

end

module:hook("stanza/jabber:component:accept:handshake", function(event)

	session.type = "component";

	module:log("debug", "Handshake complete");

	module:fire_event("component_client/connected", {});

	return true; -- READY!

end);

module:hook("route/remote", function(event)

	return session and session.send(event.stanza);

end);

function stream_callbacks.handlestanza(session, stanza)

	-- Namespaces are icky.

	if not stanza.attr.xmlns and stanza.name == "handshake" then

		stanza.attr.xmlns = xmlns_component;

	end

	if not stanza.attr.xmlns or stanza.attr.xmlns == "jabber:client" then

		if not stanza.attr.from then

			session.log("warn", "Rejecting stanza with no 'from' address");

			session.send(st.error_reply(stanza, "modify", "bad-request", "Components MUST get a 'from' address on stanzas"));

			return;

		end

		local _, domain = jid_split(stanza.attr.to);

		if not domain then

			session.log("warn", "Rejecting stanza with no 'to' address");

			session.send(st.error_reply(stanza, "modify", "bad-request", "Components MUST get a 'to' address on stanzas"));

			return;

		elseif domain ~= session.host then

			session.log("warn", "Component received stanza with unknown 'to' address");

			session.send(st.error_reply(stanza, "cancel", "not-allowed", "Component doesn't serve this JID"));

			return;

		end

	end

	return core_process_stanza(session, stanza);

end

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

local default_stream_attr = { ["xmlns:stream"] = "http://etherx.jabber.org/streams", xmlns = stream_callbacks.default_ns, version = "1.0", id = "" };

local function session_close(session, reason)

	if session.destroyed then return; end

	if session.conn then

		if session.notopen then

			session.send("<?xml version='1.0'?>");

			session.send(st.stanza("stream:stream", default_stream_attr):top_tag());

		end

		if reason then

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

				module: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

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

					session.send(stanza);

				elseif reason.name then -- a stanza

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

					session.send(reason);

				end

			end

		end

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

		session.conn:close();

		listener.ondisconnect(session.conn, "stream error");

	end

end

function listener.onconnect(conn)

	session = { type = "component_unauthed", conn = conn, send = function (data) return conn:write(tostring(data)); end, host = module.host };

	-- Logging functions --

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

	session.log = logger.init(conn_name);

	session.close = session_close;

	session.log("info", "Outgoing Jabber component connection");

	local stream = new_xmpp_stream(session, stream_callbacks);

	session.stream = stream;

	function session.data(conn, data)

		local ok, err = stream:feed(data);

		if ok then return; end

		module:log("debug", "Received invalid XML (%s) %d bytes: %s", tostring(err), #data, data:sub(1, 300):gsub("[\r\n]+", " "):gsub("[%z\1-\31]", "_"));

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

	end

	session.dispatch_stanza = stream_callbacks.handlestanza;

	session.notopen = true;

	session.send(st.stanza("stream:stream", {

		to = session.host;

		["xmlns:stream"] = 'http://etherx.jabber.org/streams';

		xmlns = xmlns_component;

	}):top_tag());

	--sessions[conn] = session;

end

function listener.onincoming(conn, data)

	--local session = sessions[conn];

	session.data(conn, data);

end

function listener.ondisconnect(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.on_destroy then session:on_destroy(err); end

		--sessions[conn] = nil;

		for k in pairs(session) do

			if k ~= "log" and k ~= "close" then

				session[k] = nil;

			end

		end

		session.destroyed = true;

		session = nil;

	end

	__conn = nil;

	module:log("error", "connection lost");

	module:fire_event("component_client/disconnected", { reason = err });

	if exit_on_disconnect and not prosody.shutdown_reason then

		prosody.shutdown("Shutdown by component_client disconnect", 1);

	end

end

-- send whitespace keep-alive one an hour

if keepalive_interval ~= 0 then

	module:add_timer(keepalive_interval, function()

		if __conn then

			__conn:write(" ");

		end

		return keepalive_interval;

	end);

end

function connect()

	------------------------

	-- Taken from net.http

	local conn = socket.tcp ( )

	conn:settimeout ( 10 )

	local ok, err = conn:connect ( server_host , server_port )

	if not ok and err ~= "timeout" then

		return nil, err;

	end

	local handler , conn = server.wrapclient ( conn , server_host , server_port , listener , "*a")

	__conn = handler;

	------------------------

	return true;

end

local s, err = connect();

if not s then

	listener.ondisconnect(nil, err);

end

module:hook_global("server-stopping", function(event)

	local reason = event.reason;

	if session then

		session:close{ condition = "system-shutdown", text = reason };

	end

end, 1000);