-- 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.
--

local datamanager = require "util.datamanager";
local datetime = require "util.datetime";

local jid_split = require "util.jid".split;
local jid_bare = require "util.jid".bare;
local st = require "util.stanza";
local log = require "util.logger".init("mod_muc");
local multitable_new = require "util.multitable".new;
local t_insert, t_remove = table.insert, table.remove;

local muc_domain = nil; --module:get_host();
local history_length = 20;

------------
local function filter_xmlns_from_array(array, filters)
	local count = 0;
	for i=#array,1,-1 do
		local attr = array[i].attr;
		if filters[attr and attr.xmlns] then
			t_remove(array, i);
			count = count + 1;
		end
	end
	return count;
end
local function filter_xmlns_from_stanza(stanza, filters)
	if filters then
		if filter_xmlns_from_array(stanza.tags, filters) ~= 0 then
			return stanza, filter_xmlns_from_array(stanza, filters);
		end
	end
	return stanza, 0;
end
local presence_filters = {["http://jabber.org/protocol/muc"]=true;["http://jabber.org/protocol/muc#user"]=true};
local function get_filtered_presence(stanza)
	return filter_xmlns_from_stanza(st.clone(stanza), presence_filters);
end
local kickable_error_conditions = {
	["gone"] = true;
	["internal-server-error"] = true;
	["item-not-found"] = true;
	["jid-malformed"] = true;
	["recipient-unavailable"] = true;
	["redirect"] = true;
	["remote-server-not-found"] = true;
	["remote-server-timeout"] = true;
	["service-unavailable"] = true;
};
local function get_kickable_error(stanza)
	for _, tag in ipairs(stanza.tags) do
		if tag.name == "error" and tag.attr.xmlns == "jabber:client" then
			for _, cond in ipairs(tag.tags) do
				if cond.attr.xmlns == "urn:ietf:params:xml:ns:xmpp-stanzas" then
					return kickable_error_conditions[cond.name] and cond.name;
				end
			end
			return true; -- malformed error message
		end
	end
	return true; -- malformed error message
end
local function getUsingPath(stanza, path, getText)
	local tag = stanza;
	for _, name in ipairs(path) do
		if type(tag) ~= 'table' then return; end
		tag = tag:child_with_name(name);
	end
	if tag and getText then tag = table.concat(tag); end
	return tag;
end
local function getTag(stanza, path) return getUsingPath(stanza, path); end
local function getText(stanza, path) return getUsingPath(stanza, path, true); end
-----------

--[[function get_room_disco_info(room, stanza)
	return st.iq({type='result', id=stanza.attr.id, from=stanza.attr.to, to=stanza.attr.from}):query("http://jabber.org/protocol/disco#info")
		:tag("identity", {category='conference', type='text', name=room._data["name"]):up()
		:tag("feature", {var="http://jabber.org/protocol/muc"}); -- TODO cache disco reply
end
function get_room_disco_items(room, stanza)
	return st.iq({type='result', id=stanza.attr.id, from=stanza.attr.to, to=stanza.attr.from}):query("http://jabber.org/protocol/disco#items");
end -- TODO allow non-private rooms]]

--

local function room_broadcast_presence(room, stanza, code, nick)
	stanza = get_filtered_presence(stanza);
	local data = room._participants[stanza.attr.from];
	stanza:tag("x", {xmlns='http://jabber.org/protocol/muc#user'})
		:tag("item", {affiliation=data.affiliation, role=data.role, nick=nick}):up();
	if code then
		stanza:tag("status", {code=code}):up();
	end
	local me;
	for occupant, o_data in pairs(room._participants) do
		if occupant ~= stanza.attr.from then
			for jid in pairs(o_data.sessions) do
				stanza.attr.to = jid;
				room:route_stanza(stanza);
			end
		else
			me = o_data;
		end
	end
	if me then
		stanza:tag("status", {code='110'});
		for jid in pairs(me.sessions) do
			stanza.attr.to = jid;
			room:route_stanza(stanza);
		end
	end
end
local function room_broadcast_message(room, stanza, historic)
	for occupant, o_data in pairs(room._participants) do
		for jid in pairs(o_data.sessions) do
			stanza.attr.to = jid;
			room:route_stanza(stanza);
		end
	end
	if historic then -- add to history
		local history = room._data['history'];
		if not history then history = {}; room._data['history'] = history; end
		-- stanza = st.clone(stanza);
		stanza:tag("delay", {xmlns = "urn:xmpp:delay", from = muc_domain, stamp = datetime.datetime()}):up(); -- XEP-0203
		stanza:tag("x", {xmlns = "jabber:x:delay", from = muc_domain, stamp = datetime.legacy()}):up(); -- XEP-0091 (deprecated)
		t_insert(history, st.clone(st.preserialize(stanza)));
		while #history > history_length do t_remove(history, 1) end
	end
end


local function room_send_occupant_list(room, to)
	local current_nick = room._jid_nick[to];
	for occupant, o_data in pairs(room._participants) do
		if occupant ~= current_nick then
			local pres = get_filtered_presence(o_data.sessions[o_data.jid]);
			pres.attr.to, pres.attr.from = to, occupant;
			pres:tag("x", {xmlns='http://jabber.org/protocol/muc#user'})
				:tag("item", {affiliation=o_data.affiliation, role=o_data.role}):up();
			room:route_stanza(pres);
		end
	end
end
local function room_send_history(room, to)
	local history = room._data['history']; -- send discussion history
	if history then
		for _, msg in ipairs(history) do
			msg = st.deserialize(msg);
			msg.attr.to=to;
			room:route_stanza(msg);
		end
	end
	if room._data['subject'] then
		room:route_stanza(st.message({type='groupchat', from=room, to=to}):tag("subject"):text(room._data['subject']));
	end
end

local function room_get_disco_info(self, stanza) end
local function room_get_disco_items(self, stanza) end
local function room_set_subject(room, current_nick, room, subject)
	-- TODO check nick's authority
	if subject == "" then subject = nil; end
	room._data['subject'] = subject;
	local msg = st.message({type='groupchat', from=current_nick})
		:tag('subject'):text(subject):up();
	room_broadcast_message(room, msg, false);
	return true;
end

local function room_handle_to_occupant(self, origin, stanza) -- PM, vCards, etc
	local from, to = stanza.attr.from, stanza.attr.to;
	local room = jid_bare(to);
	local current_nick = self._jid_nick[from];
	local type = stanza.attr.type;
	log("debug", "room: %s, current_nick: %s, stanza: %s", room or "nil", current_nick or "nil", stanza:top_tag());
	if (select(2, jid_split(from)) == muc_domain) then error("Presence from the MUC itself!!!"); end
	if stanza.name == "presence" then
		local pr = get_filtered_presence(stanza);
		pr.attr.from = current_nick;
		if type == "error" then -- error, kick em out!
			if current_nick then
				log("debug", "kicking %s from %s", current_nick, room);
				room_handle_to_occupant(self, origin, st.presence({type='unavailable', from=from, to=to}):tag('status'):text('This participant is kicked from the room because he sent an error presence')); -- send unavailable
			end
		elseif type == "unavailable" then -- unavailable
			if current_nick then
				log("debug", "%s leaving %s", current_nick, room);
				local data = self._participants[current_nick];
				data.role = 'none';
				room_broadcast_presence(self, pr);
				self._participants[current_nick] = nil;
				self._jid_nick[from] = nil;
			end
		elseif not type then -- available
			if current_nick then
				--if #pr == #stanza or current_nick ~= to then -- commented because google keeps resending directed presence
					if current_nick == to then -- simple presence
						log("debug", "%s broadcasted presence", current_nick);
						self._participants[current_nick].sessions[from] = pr;
						room_broadcast_presence(self, pr);
					else -- change nick
						if self._participants[to] then
							log("debug", "%s couldn't change nick", current_nick);
							origin.send(st.error_reply(stanza, "cancel", "conflict"));
						else
							local data = self._participants[current_nick];
							local to_nick = select(3, jid_split(to));
							if to_nick then
								log("debug", "%s (%s) changing nick to %s", current_nick, data.jid, to);
								local p = st.presence({type='unavailable', from=current_nick});
								room_broadcast_presence(self, p, '303', to_nick);
								self._participants[current_nick] = nil;
								self._participants[to] = data;
								self._jid_nick[from] = to;
								pr.attr.from = to;
								self._participants[to].sessions[from] = pr;
								room_broadcast_presence(self, pr);
							else
								--TODO malformed-jid
							end
						end
					end
				--else -- possible rejoin
				--	log("debug", "%s had connection replaced", current_nick);
				--	handle_to_occupant(origin, st.presence({type='unavailable', from=from, to=to}):tag('status'):text('Replaced by new connection'):up()); -- send unavailable
				--	handle_to_occupant(origin, stanza); -- resend available
				--end
			else -- enter room
				local new_nick = to;
				if self._participants[to] then
					new_nick = nil;
				end
				if not new_nick then
					log("debug", "%s couldn't join due to nick conflict: %s", from, to);
					origin.send(st.error_reply(stanza, "cancel", "conflict"));
				else
					log("debug", "%s joining as %s", from, to);
					local data;
--					if not rooms:get(room) and not rooms_info:get(room) then -- new room
--						rooms_info:set(room, 'name', (jid_split(room)));
--						data = {affiliation='owner', role='moderator', jid=from, sessions={[from]=get_filtered_presence(stanza)}};
--					end
					if not data then -- new occupant
						data = {affiliation='none', role='participant', jid=from, sessions={[from]=get_filtered_presence(stanza)}};
					end
					self._participants[to] = data;
					self._jid_nick[from] = to;
					room_send_occupant_list(self, from);
					pr.attr.from = to;
					room_broadcast_presence(self, pr);
					room_send_history(self, from);
				end
			end
		elseif type ~= 'result' then -- bad type
			origin.send(st.error_reply(stanza, "modify", "bad-request")); -- FIXME correct error?
		end
	elseif not current_nick and type ~= "error" and type ~= "result" then -- not in room
		origin.send(st.error_reply(stanza, "cancel", "not-acceptable"));
	elseif stanza.name == "message" and type == "groupchat" then -- groupchat messages not allowed in PM
		origin.send(st.error_reply(stanza, "modify", "bad-request"));
	elseif stanza.name == "message" and type == "error" and get_kickable_error(stanza) then
		log("debug", "%s kicked from %s for sending an error message", current_nick, room);
		room_handle_to_occupant(self, origin, st.presence({type='unavailable', from=from, to=to}):tag('status'):text('This participant is kicked from the room because he sent an error message to another occupant')); -- send unavailable
	else -- private stanza
		local o_data = self._participants[to];
		if o_data then
			log("debug", "%s sent private stanza to %s (%s)", from, to, o_data.jid);
			local jid = o_data.jid;
			-- TODO if stanza.name=='iq' and type=='get' and stanza.tags[1].attr.xmlns == 'vcard-temp' then jid = jid_bare(jid); end
			stanza.attr.to, stanza.attr.from = jid, current_nick;
			self:route_stanza(stanza);
		elseif type ~= "error" and type ~= "result" then -- recipient not in room
			origin.send(st.error_reply(stanza, "cancel", "item-not-found", "Recipient not in room"));
		end
	end
end

local function room_handle_to_room(self, origin, stanza) -- presence changes and groupchat messages, along with disco/etc
	local type = stanza.attr.type;
	if stanza.name == "iq" and type == "get" then -- disco requests
		local xmlns = stanza.tags[1].attr.xmlns;
		if xmlns == "http://jabber.org/protocol/disco#info" then
			origin.send(room_get_disco_info(self, stanza));
		elseif xmlns == "http://jabber.org/protocol/disco#items" then
			origin.send(room_get_disco_items(self, stanza));
		else
			origin.send(st.error_reply(stanza, "cancel", "service-unavailable"));
		end
	elseif stanza.name == "message" and type == "groupchat" then
		local from, to = stanza.attr.from, stanza.attr.to;
		local room = jid_bare(to);
		local current_nick = self._jid_nick[from];
		if not current_nick then -- not in room
			origin.send(st.error_reply(stanza, "cancel", "not-acceptable"));
		else
			local from = stanza.attr.from;
			stanza.attr.from = current_nick;
			local subject = getText(stanza, {"subject"});
			if subject then
				self:set_subject(current_nick, subject); -- TODO use broadcast_message_stanza
			else
				room_broadcast_message(self, stanza, true);
			end
		end
	elseif stanza.name == "presence" then -- hack - some buggy clients send presence updates to the room rather than their nick
		local to = stanza.attr.to;
		local current_nick = self._jid_nick[stanza.attr.from];
		if current_nick then
			stanza.attr.to = current_nick;
			room_handle_to_occupant(origin, stanza);
			stanza.attr.to = to;
		elseif type ~= "error" and type ~= "result" then
			origin.send(st.error_reply(stanza, "cancel", "service-unavailable"));
		end
	elseif stanza.name == "message" and not stanza.attr.type and #stanza.tags == 1 and self._jid_nick[stanza.attr.from]
		and stanza.tags[1].name == "x" and stanza.tags[1].attr.xmlns == "http://jabber.org/protocol/muc#user" and #stanza.tags[1].tags == 1
		and stanza.tags[1].tags[1].name == "invite" and stanza.tags[1].tags[1].attr.to then
		local _from, _to = stanza.attr.from, stanza.attr.to;
		local _invitee = stanza.tags[1].tags[1].attr.to;
		stanza.attr.from, stanza.attr.to = _to, _invitee;
		stanza.tags[1].tags[1].attr.from, stanza.tags[1].tags[1].attr.to = _from, nil;
		self:route_stanza(stanza);
		stanza.tags[1].tags[1].attr.from, stanza.tags[1].tags[1].attr.to = nil, _invitee;
		stanza.attr.from, stanza.attr.to = _from, _to;
	else
		if type == "error" or type == "result" then return; end
		origin.send(st.error_reply(stanza, "cancel", "service-unavailable"));
	end
end

local function room_handle_stanza(self, origin, stanza)
	local to_node, to_host, to_resource = jid_split(stanza.attr.to);
	if to_resource then
		room_handle_to_occupant(self, origin, stanza);
	else
		room_handle_to_room(self, origin, stanza);
	end
end

module "muc"

function new_room(jid)
	return {
		jid = jid;
		handle_stanza = room_handle_stanza;
		set_subject = room_set_subject;
		route_stanza = function(room, stanza) end; -- Replace with a routing function, e.g., function(room, stanza) core_route_stanza(origin, stanza); end
		_jid_nick = {};
		_participants = {};
		_data = {};
	}
end

return _M;

--[[function get_disco_info(stanza)
	return st.iq({type='result', id=stanza.attr.id, from=muc_domain, to=stanza.attr.from}):query("http://jabber.org/protocol/disco#info")
		:tag("identity", {category='conference', type='text', name=muc_name}):up()
		:tag("feature", {var="http://jabber.org/protocol/muc"}); -- TODO cache disco reply
end
function get_disco_items(stanza)
	local reply = st.iq({type='result', id=stanza.attr.id, from=muc_domain, to=stanza.attr.from}):query("http://jabber.org/protocol/disco#items");
	for room in pairs(rooms_info:get()) do
		reply:tag("item", {jid=room, name=rooms_info:get(room, "name")}):up();
	end
	return reply; -- TODO cache disco reply
end]]

--[[function handle_to_domain(origin, stanza)
	local type = stanza.attr.type;
	if type == "error" or type == "result" then return; end
	if stanza.name == "iq" and type == "get" then
		local xmlns = stanza.tags[1].attr.xmlns;
		if xmlns == "http://jabber.org/protocol/disco#info" then
			origin.send(get_disco_info(stanza));
		elseif xmlns == "http://jabber.org/protocol/disco#items" then
			origin.send(get_disco_items(stanza));
		else
			origin.send(st.error_reply(stanza, "cancel", "service-unavailable")); -- TODO disco/etc
		end
	else
		origin.send(st.error_reply(stanza, "cancel", "service-unavailable", "The muc server doesn't deal with messages and presence directed at it"));
	end
end

register_component(muc_domain, function(origin, stanza)
	local to_node, to_host, to_resource = jid_split(stanza.attr.to);
	if to_resource and not to_node then
		if type == "error" or type == "result" then return; end
		origin.send(st.error_reply(stanza, "cancel", "service-unavailable")); -- host/resource
	elseif to_resource then
		handle_to_occupant(origin, stanza);
	elseif to_node then
		handle_to_room(origin, stanza)
	else -- to the main muc domain
		if type == "error" or type == "result" then return; end
		handle_to_domain(origin, stanza);
	end
end);]]

--[[module.unload = function()
	deregister_component(muc_domain);
end
module.save = function()
	return {rooms = rooms.data; jid_nick = jid_nick.data; rooms_info = rooms_info.data; persist_list = persist_list};
end
module.restore = function(data)
	rooms.data, jid_nick.data, rooms_info.data, persist_list =
	data.rooms or {}, data.jid_nick or {}, data.rooms_info or {}, data.persist_list or {};
end]]