-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- 

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

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

--

local hosts = _G.hosts;

local t_concat = table.concat;

local lxp = require "lxp";

local logger = require "util.logger";

local config = require "core.configmanager";

local connlisteners = require "net.connlisteners";

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

local cm_deregister_component = require "core.componentmanager".deregister_component;

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

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

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

local st = require "util.stanza";

local init_xmlhandlers = require "core.xmlhandlers";

local sessions = {};

local log = logger.init("componentlistener");

local component_listener = { default_port = 5347; default_mode = "*a"; default_interface = config.get("*", "core", "component_interface") or "127.0.0.1" };

local xmlns_component = 'jabber:component:accept';

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

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

	log("warn", "Error processing component stream: "..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("xml-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)

	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

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

	-- until after the external component auths successfully

	session.host = attr.to;

	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)

	session:close();

end

local core_process_stanza = core_process_stanza;

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

		local from = stanza.attr.from;

		if from then

			if session.component_validate_from then

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

				if domain ~= session.host then

					-- Return error

					session.log("warn", "Component sent stanza with missing or invalid 'from' address");

					session:close{

						condition = "invalid-from";

						text = "Component tried to send from address <"..tostring(from)

							   .."> which is not in domain <"..tostring(session.host)..">";

					};

					return;

				end

			end

		else

			stanza.attr.from = session.host;

		end

		if not stanza.attr.to then

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

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

			return;

		end

	end

	return core_process_stanza(session, stanza);

end

--- Closing a component connection

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

	local log = session.log or log;

	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

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

	end

end

--- Component connlistener

function component_listener.onincoming(conn, data)

	local session = sessions[conn];

	if not session then

		local _send = conn.write;

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

		sessions[conn] = session;

		-- Logging functions --

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

		session.log = logger.init(conn_name);

		session.close = session_close;

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

		local parser = lxp.new(init_xmlhandlers(session, stream_callbacks), "\1");

		session.parser = parser;

		session.notopen = true;

		function session.data(conn, data)

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

			if ok then return; end

			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("xml-not-well-formed");

		end

		session.dispatch_stanza = stream_callbacks.handlestanza;

	end

	if data then

		session.data(conn, data);

	end

end

function component_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.host then

			log("debug", "Deregistering component");

			cm_deregister_component(session.host);

			hosts[session.host].connected = nil;

		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

end

connlisteners.register('xmppcomponent', component_listener);