-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
-- Copyright (C) 2014 Daurnimator
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local select = select;
local pairs, ipairs = pairs, ipairs;

local gettime = os.time;
local datetime = require "util.datetime";

local dataform = require "util.dataforms";

local jid_split = require "util.jid".split;
local jid_bare = require "util.jid".bare;
local jid_prep = require "util.jid".prep;
local st = require "util.stanza";
local log = require "util.logger".init("mod_muc");
local t_insert, t_remove = table.insert, table.remove;
local setmetatable = setmetatable;
local base64 = require "util.encodings".base64;
local md5 = require "util.hashes".md5;

local default_history_length, max_history_length = 20, math.huge;

local get_filtered_presence do
	local presence_filters = {
		["http://jabber.org/protocol/muc"] = true;
		["http://jabber.org/protocol/muc#user"] = true;
	}
	local function presence_filter(tag)
		if presence_filters[tag.attr.xmlns] then
			return nil;
		end
		return tag;
	end
	function get_filtered_presence(stanza)
		return st.clone(stanza):maptags(presence_filter);
	end
end

local is_kickable_error do
	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;
		["malformed error"] = true;
	};
	function is_kickable_error(stanza)
		local cond = select(2, stanza:get_error()) or "malformed error";
		return kickable_error_conditions[cond];
	end
end

local room_mt = {};
room_mt.__index = room_mt;

function room_mt:__tostring()
	return "MUC room ("..self.jid..")";
end

function room_mt:get_occupant_jid(real_jid)
	return self._jid_nick[real_jid]
end

function room_mt:get_default_role(affiliation)
	if affiliation == "owner" or affiliation == "admin" then
		return "moderator";
	elseif affiliation == "member" then
		return "participant";
	elseif not affiliation then
		if not self:get_members_only() then
			return self:get_moderated() and "visitor" or "participant";
		end
	end
end

function room_mt:lock()
	self.locked = true
end
function room_mt:unlock()
	module:fire_event("muc-room-unlocked", { room = self });
	self.locked = nil
end
function room_mt:is_locked()
	return not not self.locked
end

function room_mt:route_to_occupant(o_data, stanza)
	local to = stanza.attr.to;
	for jid in pairs(o_data.sessions) do
		stanza.attr.to = jid;
		self:_route_stanza(stanza);
	end
	stanza.attr.to = to;
end

function room_mt:broadcast_presence(stanza, sid, code, nick)
	stanza = get_filtered_presence(stanza);
	local occupant = self._occupants[stanza.attr.from];
	stanza:tag("x", {xmlns='http://jabber.org/protocol/muc#user'})
		:tag("item", {affiliation=occupant.affiliation or "none", role=occupant.role or "none", nick=nick}):up();
	if code then
		stanza:tag("status", {code=code}):up();
	end
	self:broadcast_except_nick(stanza, stanza.attr.from);
	stanza:tag("status", {code='110'}):up();
	stanza.attr.to = sid;
	self:_route_stanza(stanza);
end
function room_mt:broadcast_message(stanza, historic)
	module:fire_event("muc-broadcast-message", {room = self, stanza = stanza, historic = historic});
	self:broadcast(stanza);
end

-- add to history
module:hook("muc-broadcast-message", function(event)
	if event.historic then
		local room = event.room
		local history = room._data['history'];
		if not history then history = {}; room._data['history'] = history; end
		local stanza = st.clone(event.stanza);
		stanza.attr.to = "";
		local ts = gettime();
		local stamp = datetime.datetime(ts);
		stanza:tag("delay", {xmlns = "urn:xmpp:delay", from = module.host, stamp = stamp}):up(); -- XEP-0203
		stanza:tag("x", {xmlns = "jabber:x:delay", from = module.host, stamp = datetime.legacy()}):up(); -- XEP-0091 (deprecated)
		local entry = { stanza = stanza, timestamp = ts };
		t_insert(history, entry);
		while #history > room:get_historylength() do t_remove(history, 1) end
	end
end)

function room_mt:broadcast_except_nick(stanza, nick)
	return self:broadcast(stanza, function(rnick, occupant) return rnick ~= nick end)
end

-- Broadcast a stanza to all occupants in the room.
-- optionally checks conditional called with nicl
function room_mt:broadcast(stanza, cond_func)
	for nick, occupant in pairs(self._occupants) do
		if cond_func == nil or cond_func(nick, occupant) then
			self:route_to_occupant(occupant, stanza)
		end
	end
end

function room_mt:send_occupant_list(to)
	local current_nick = self:get_occupant_jid(to);
	for occupant, o_data in pairs(self._occupants) 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 or "none", role=o_data.role or "none"}):up();
			self:_route_stanza(pres);
		end
	end
end

local function parse_history(stanza)
	local x_tag = stanza:get_child("x", "http://jabber.org/protocol/muc");
	local history_tag = x_tag and x_tag:get_child("history", "http://jabber.org/protocol/muc");
	if not history_tag then
		return nil, 20, nil
	end

	local maxchars = tonumber(history_tag.attr.maxchars);

	local maxstanzas = tonumber(history_tag.attr.maxstanzas);

	-- messages received since the UTC datetime specified
	local since = history_tag.attr.since;
	if since then
		since = datetime.parse(since);
	end

	-- messages received in the last "X" seconds.
	local seconds = tonumber(history_tag.attr.seconds);
	if seconds then
		seconds = gettime() - seconds
		if since then
			since = math.max(since, seconds);
		else
			since = seconds;
		end
	end

	return maxchars, maxstanzas, since
end

module:hook("muc-get-history", function(event)
	local room = event.room
	local history = room._data['history']; -- send discussion history
	if not history then return nil end
	local history_len = #history

	local to = event.to
	local maxchars = event.maxchars
	local maxstanzas = event.maxstanzas or history_len
	local since = event.since
	local n = 0;
	local charcount = 0;
	for i=history_len,1,-1 do
		local entry = history[i];
		if maxchars then
			if not entry.chars then
				entry.stanza.attr.to = "";
				entry.chars = #tostring(entry.stanza);
			end
			charcount = charcount + entry.chars + #to;
			if charcount > maxchars then break; end
		end
		if since and since > entry.timestamp then break; end
		if n + 1 > maxstanzas then break; end
		n = n + 1;
	end

	local i = history_len-n+1
	function event:next_stanza()
		if i > history_len then return nil end
		local entry = history[i]
		local msg = entry.stanza
		msg.attr.to = to;
		i = i + 1
		return msg
	end
	return true;
end)

function room_mt:send_history(stanza)
	local maxchars, maxstanzas, since = parse_history(stanza)
	local event = {
		room = self;
		to = stanza.attr.from; -- `to` is required to calculate the character count for `maxchars`
		maxchars = maxchars, maxstanzas = maxstanzas, since = since;
		next_stanza = function() end; -- events should define this iterator
	}
	module:fire_event("muc-get-history", event)
	for msg in event.next_stanza , event do
		self:_route_stanza(msg);
	end
end

function room_mt:get_disco_info(stanza)
	local count = 0; for _ in pairs(self._occupants) do count = count + 1; end
	return st.reply(stanza):query("http://jabber.org/protocol/disco#info")
		:tag("identity", {category="conference", type="text", name=self:get_name()}):up()
		:tag("feature", {var="http://jabber.org/protocol/muc"}):up()
		:tag("feature", {var=self:get_password() and "muc_passwordprotected" or "muc_unsecured"}):up()
		:tag("feature", {var=self:get_moderated() and "muc_moderated" or "muc_unmoderated"}):up()
		:tag("feature", {var=self:get_members_only() and "muc_membersonly" or "muc_open"}):up()
		:tag("feature", {var=self:get_persistent() and "muc_persistent" or "muc_temporary"}):up()
		:tag("feature", {var=self:get_hidden() and "muc_hidden" or "muc_public"}):up()
		:tag("feature", {var=self:get_whois() ~= "anyone" and "muc_semianonymous" or "muc_nonanonymous"}):up()
		:add_child(dataform.new({
			{ name = "FORM_TYPE", type = "hidden", value = "http://jabber.org/protocol/muc#roominfo" },
			{ name = "muc#roominfo_description", label = "Description", value = "" },
			{ name = "muc#roominfo_occupants", label = "Number of occupants", value = tostring(count) }
		}):form({["muc#roominfo_description"] = self:get_description()}, 'result'))
	;
end
function room_mt:get_disco_items(stanza)
	local reply = st.reply(stanza):query("http://jabber.org/protocol/disco#items");
	for room_jid in pairs(self._occupants) do
		reply:tag("item", {jid = room_jid, name = room_jid:match("/(.*)")}):up();
	end
	return reply;
end

function room_mt:get_subject()
	return self._data['subject'], self._data['subject_from']
end
local function create_subject_message(subject)
	return st.message({type='groupchat'})
		:tag('subject'):text(subject):up();
end
function room_mt:send_subject(to)
	local from, subject = self:get_subject()
	if subject then
		local msg = create_subject_message(subject)
		msg.attr.from = from
		msg.attr.to = to
		self:_route_stanza(msg);
	end
end
function room_mt:set_subject(current_nick, subject)
	if subject == "" then subject = nil; end
	self._data['subject'] = subject;
	self._data['subject_from'] = current_nick;
	if self.save then self:save(); end
	local msg = create_subject_message(subject)
	msg.attr.from = current_nick
	self:broadcast_message(msg, false);
	return true;
end

function room_mt:handle_kickable(origin, stanza)
	local type, condition, text = stanza:get_error();
	local error_message = "Kicked: "..(condition and condition:gsub("%-", " ") or "presence error");
	if text then
		error_message = error_message..": "..text;
	end
	local kick_stanza = st.presence({type='unavailable', from=stanza.attr.from, to=stanza.attr.to})
		:tag('status'):text(error_message);
	self:handle_unavailable_to_occupant(origin, kick_stanza); -- send unavailable
	return true;
end

function room_mt:set_name(name)
	if name == "" or type(name) ~= "string" or name == (jid_split(self.jid)) then name = nil; end
	if self._data.name ~= name then
		self._data.name = name;
		if self.save then self:save(true); end
	end
end
function room_mt:get_name()
	return self._data.name or jid_split(self.jid);
end
function room_mt:set_description(description)
	if description == "" or type(description) ~= "string" then description = nil; end
	if self._data.description ~= description then
		self._data.description = description;
		if self.save then self:save(true); end
	end
end
function room_mt:get_description()
	return self._data.description;
end
function room_mt:set_password(password)
	if password == "" or type(password) ~= "string" then password = nil; end
	if self._data.password ~= password then
		self._data.password = password;
		if self.save then self:save(true); end
	end
end
function room_mt:get_password()
	return self._data.password;
end
function room_mt:set_moderated(moderated)
	moderated = moderated and true or nil;
	if self._data.moderated ~= moderated then
		self._data.moderated = moderated;
		if self.save then self:save(true); end
	end
end
function room_mt:get_moderated()
	return self._data.moderated;
end
function room_mt:set_members_only(members_only)
	members_only = members_only and true or nil;
	if self._data.members_only ~= members_only then
		self._data.members_only = members_only;
		if self.save then self:save(true); end
	end
end
function room_mt:get_members_only()
	return self._data.members_only;
end
function room_mt:set_persistent(persistent)
	persistent = persistent and true or nil;
	if self._data.persistent ~= persistent then
		self._data.persistent = persistent;
		if self.save then self:save(true); end
	end
end
function room_mt:get_persistent()
	return self._data.persistent;
end
function room_mt:set_hidden(hidden)
	hidden = hidden and true or nil;
	if self._data.hidden ~= hidden then
		self._data.hidden = hidden;
		if self.save then self:save(true); end
	end
end
function room_mt:get_hidden()
	return self._data.hidden;
end
function room_mt:get_public()
	return not self:get_hidden();
end
function room_mt:set_public(public)
	return self:set_hidden(not public);
end
function room_mt:set_changesubject(changesubject)
	changesubject = changesubject and true or nil;
	if self._data.changesubject ~= changesubject then
		self._data.changesubject = changesubject;
		if self.save then self:save(true); end
	end
end
function room_mt:get_changesubject()
	return self._data.changesubject;
end
function room_mt:get_historylength()
	return self._data.history_length or default_history_length;
end
function room_mt:set_historylength(length)
	length = math.min(tonumber(length) or default_history_length, max_history_length or math.huge);
	if length == default_history_length then
		length = nil;
	end
	self._data.history_length = length;
end


local valid_whois = { moderators = true, anyone = true };

function room_mt:set_whois(whois)
	if valid_whois[whois] and self._data.whois ~= whois then
		self._data.whois = whois;
		if self.save then self:save(true); end
	end
end

function room_mt:get_whois()
	return self._data.whois;
end

function room_mt:handle_unavailable_to_occupant(origin, stanza)
	local from = stanza.attr.from;
	local current_nick = self:get_occupant_jid(from);
	if not current_nick then
		return true; -- discard
	end
	local pr = get_filtered_presence(stanza);
	pr.attr.from = current_nick;
	log("debug", "%s leaving %s", current_nick, self.jid);
	self._jid_nick[from] = nil;
	local occupant = self._occupants[current_nick];
	local new_jid = next(occupant.sessions);
	if new_jid == from then new_jid = next(occupant.sessions, new_jid); end
	if new_jid then
		local jid = occupant.jid;
		occupant.jid = new_jid;
		occupant.sessions[from] = nil;
		pr.attr.to = from;
		pr:tag("x", {xmlns='http://jabber.org/protocol/muc#user'})
			:tag("item", {affiliation=occupant.affiliation or "none", role='none'}):up()
			:tag("status", {code='110'}):up();
		self:_route_stanza(pr);
		if jid ~= new_jid then
			pr = st.clone(occupant.sessions[new_jid])
				:tag("x", {xmlns='http://jabber.org/protocol/muc#user'})
				:tag("item", {affiliation=occupant.affiliation or "none", role=occupant.role or "none"});
			pr.attr.from = current_nick;
			self:broadcast_except_nick(pr, current_nick);
		end
	else
		occupant.role = 'none';
		self:broadcast_presence(pr, from);
		self._occupants[current_nick] = nil;
		module:fire_event("muc-occupant-left", { room = self; nick = current_nick; });
	end
	return true;
end

function room_mt:handle_occupant_presence(origin, stanza)
	local from = stanza.attr.from;
	local pr = get_filtered_presence(stanza);
	local current_nick = stanza.attr.to
	pr.attr.from = current_nick;
	log("debug", "%s broadcasted presence", current_nick);
	self._occupants[current_nick].sessions[from] = pr;
	self:broadcast_presence(pr, from);
	return true;
end

function room_mt:handle_change_nick(origin, stanza, current_nick, to)
	local from = stanza.attr.from;
	local occupant = self._occupants[current_nick];
	local is_multisession = next(occupant.sessions, next(occupant.sessions));
	if self._occupants[to] or is_multisession then
		log("debug", "%s couldn't change nick", current_nick);
		local reply = st.error_reply(stanza, "cancel", "conflict"):up();
		reply.tags[1].attr.code = "409";
		origin.send(reply:tag("x", {xmlns = "http://jabber.org/protocol/muc"}));
		return true;
	else
		local to_nick = select(3, jid_split(to));
		log("debug", "%s (%s) changing nick to %s", current_nick, occupant.jid, to);
		local p = st.presence({type='unavailable', from=current_nick});
		self:broadcast_presence(p, from, '303', to_nick);
		self._occupants[current_nick] = nil;
		self._occupants[to] = occupant;
		self._jid_nick[from] = to;
		local pr = get_filtered_presence(stanza);
		pr.attr.from = to;
		self._occupants[to].sessions[from] = pr;
		self:broadcast_presence(pr, from);
		return true;
	end
end

module:hook("muc-occupant-pre-join", function(event)
	return module:fire_event("muc-occupant-pre-join/affiliation", event)
		or module:fire_event("muc-occupant-pre-join/password", event)
		or module:fire_event("muc-occupant-pre-join/locked", event)
		or module:fire_event("muc-occupant-pre-join/nick-conflict", event)
end, -1)

module:hook("muc-occupant-pre-join/password", function(event)
	local room, stanza = event.room, event.stanza;
	local from, to = stanza.attr.from, stanza.attr.to;
	local password = stanza:get_child("x", "http://jabber.org/protocol/muc");
	password = password and password:get_child_text("password", "http://jabber.org/protocol/muc");
	if not password or password == "" then password = nil; end
	if room:get_password() ~= password then
		local from, to = stanza.attr.from, stanza.attr.to;
		log("debug", "%s couldn't join due to invalid password: %s", from, to);
		local reply = st.error_reply(stanza, "auth", "not-authorized"):up();
		reply.tags[1].attr.code = "401";
		event.origin.send(reply:tag("x", {xmlns = "http://jabber.org/protocol/muc"}));
		return true;
	end
end, -1)

module:hook("muc-occupant-pre-join/nick-conflict", function(event)
	local room, stanza = event.room, event.stanza;
	local from, to = stanza.attr.from, stanza.attr.to;
	local occupant = room._occupants[to]
	if occupant -- occupant already exists
		and jid_bare(from) ~= jid_bare(occupant.jid) then -- and has different bare real jid
		log("debug", "%s couldn't join due to nick conflict: %s", from, to);
		local reply = st.error_reply(stanza, "cancel", "conflict"):up();
		reply.tags[1].attr.code = "409";
		event.origin.send(reply:tag("x", {xmlns = "http://jabber.org/protocol/muc"}));
		return true;
	end
end, -1)

module:hook("muc-occupant-pre-join/locked", function(event)
	if event.room:is_locked() then -- Deny entry
		event.origin.send(st.error_reply(event.stanza, "cancel", "item-not-found"));
		return true;
	end
end, -1)

function room_mt:handle_join(origin, stanza)
	local from, to = stanza.attr.from, stanza.attr.to;
	local affiliation = self:get_affiliation(from);
	if affiliation == nil and next(self._affiliations) == nil then -- new room, no owners
		affiliation = "owner";
		self._affiliations[jid_bare(from)] = affiliation;
		if self:is_locked() and not stanza:get_child("x", "http://jabber.org/protocol/muc") then
			self:unlock(); -- Older groupchat protocol doesn't lock
		end
	end
	if module:fire_event("muc-occupant-pre-join", {
		room = self;
		origin = origin;
		stanza = stanza;
		affiliation = affiliation;
	}) then return true; end
	log("debug", "%s joining as %s", from, to);

	local role = self:get_default_role(affiliation)
	if role then -- new occupant
		local is_merge = not not self._occupants[to]
		if not is_merge then
			self._occupants[to] = {affiliation=affiliation, role=role, jid=from, sessions={[from]=get_filtered_presence(stanza)}};
		else
			self._occupants[to].sessions[from] = get_filtered_presence(stanza);
		end
		self._jid_nick[from] = to;
		self:send_occupant_list(from);
		local pr = get_filtered_presence(stanza);
		pr.attr.from = to;
		pr:tag("x", {xmlns='http://jabber.org/protocol/muc#user'})
			:tag("item", {affiliation=affiliation or "none", role=role or "none"}):up();
		if not is_merge then
			self:broadcast_except_nick(pr, to);
		end
		pr:tag("status", {code='110'}):up();
		if self:get_whois() == 'anyone' then
			pr:tag("status", {code='100'}):up();
		end
		if self:is_locked() then
			pr:tag("status", {code='201'}):up();
		end
		pr.attr.to = from;
		self:_route_stanza(pr);
		self:send_history(from, stanza);
		self:send_subject(from);
		return true;
	end
end

-- registration required for entering members-only room
module:hook("muc-occupant-pre-join/affiliation", function(event)
	if event.affiliation == nil and event.room:get_members_only() then
		local reply = st.error_reply(event.stanza, "auth", "registration-required"):up();
		reply.tags[1].attr.code = "407";
		event.origin.send(reply:tag("x", {xmlns = "http://jabber.org/protocol/muc"}));
		return true;
	end
end, -1)

-- banned
module:hook("muc-occupant-pre-join/affiliation", function(event)
	if event.affiliation == "outcast" then
		local reply = st.error_reply(event.stanza, "auth", "forbidden"):up();
		reply.tags[1].attr.code = "403";
		event.origin.send(reply:tag("x", {xmlns = "http://jabber.org/protocol/muc"}));
		return true;
	end
end, -1)

function room_mt:handle_available_to_occupant(origin, stanza)
	local from, to = stanza.attr.from, stanza.attr.to;
	local current_nick = self:get_occupant_jid(from);
	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
				return self:handle_occupant_presence(origin, stanza)
			else -- change nick
				return self:handle_change_nick(origin, stanza, current_nick, to)
			end
		--else -- possible rejoin
		--	log("debug", "%s had connection replaced", current_nick);
		--	self:handle_to_occupant(origin, st.presence({type='unavailable', from=from, to=to})
		--		:tag('status'):text('Replaced by new connection'):up()); -- send unavailable
		--	self:handle_to_occupant(origin, stanza); -- resend available
		--end
	else -- enter room
		return self:handle_join(origin, stanza)
	end
end

function room_mt:handle_presence_to_occupant(origin, stanza)
	local type = stanza.attr.type;
	if type == "error" then -- error, kick em out!
		return self:handle_kickable(origin, stanza)
	elseif type == "unavailable" then -- unavailable
		return self:handle_unavailable_to_occupant(origin, stanza)
	elseif not type then -- available
		return self:handle_available_to_occupant(origin, stanza)
	elseif type ~= 'result' then -- bad type
		if type ~= 'visible' and type ~= 'invisible' then -- COMPAT ejabberd can broadcast or forward XEP-0018 presences
			origin.send(st.error_reply(stanza, "modify", "bad-request")); -- FIXME correct error?
		end
	end
	return true;
end

function room_mt:handle_iq_to_occupant(origin, stanza)
	local from, to = stanza.attr.from, stanza.attr.to;
	local type = stanza.attr.type;
	local id = stanza.attr.id;
	local current_nick = self:get_occupant_jid(from);
	local o_data = self._occupants[to];
	if (type == "error" or type == "result") then
		do -- deconstruct_stanza_id
			if not current_nick or not o_data then return nil; end
			local from_jid, id, to_jid_hash = (base64.decode(stanza.attr.id) or ""):match("^(.+)%z(.*)%z(.+)$");
			if not(from == from_jid or from == jid_bare(from_jid)) then return nil; end
			local session_jid
			for to_jid in pairs(o_data.sessions) do
				if md5(to_jid) == to_jid_hash then
					session_jid = to_jid;
					break;
				end
			end
			if session_jid == nil then return nil; end
			stanza.attr.from, stanza.attr.to, stanza.attr.id = current_nick, session_jid, id
		end
		log("debug", "%s sent private iq stanza to %s (%s)", from, to, stanza.attr.to);
		self:_route_stanza(stanza);
		stanza.attr.from, stanza.attr.to, stanza.attr.id = from, to, id;
		return true;
	else -- Type is "get" or "set"
		if not current_nick then
			origin.send(st.error_reply(stanza, "cancel", "not-acceptable"));
			return true;
		end
		if not o_data then -- recipient not in room
			origin.send(st.error_reply(stanza, "cancel", "item-not-found", "Recipient not in room"));
			return true;
		end
		do -- construct_stanza_id
			stanza.attr.id = base64.encode(o_data.jid.."\0"..stanza.attr.id.."\0"..md5(from));
		end
		stanza.attr.from, stanza.attr.to = current_nick, o_data.jid;
		log("debug", "%s sent private iq stanza to %s (%s)", from, to, o_data.jid);
		if stanza.tags[1].attr.xmlns == 'vcard-temp' then
			stanza.attr.to = jid_bare(stanza.attr.to);
		end
		self:_route_stanza(stanza);
		stanza.attr.from, stanza.attr.to, stanza.attr.id = from, to, id;
		return true;
	end
end

function room_mt:handle_message_to_occupant(origin, stanza)
	local from, to = stanza.attr.from, stanza.attr.to;
	local current_nick = self:get_occupant_jid(from);
	local type = stanza.attr.type;
	if not current_nick then -- not in room
		if type ~= "error" then
			origin.send(st.error_reply(stanza, "cancel", "not-acceptable"));
		end
		return true;
	end
	if type == "groupchat" then -- groupchat messages not allowed in PM
		origin.send(st.error_reply(stanza, "modify", "bad-request"));
		return true;
	elseif type == "error" and is_kickable_error(stanza) then
		log("debug", "%s kicked from %s for sending an error message", current_nick, self.jid);
		return self:handle_kickable(origin, stanza); -- send unavailable
	end

	local o_data = self._occupants[to];
	if not o_data then
		origin.send(st.error_reply(stanza, "cancel", "item-not-found", "Recipient not in room"));
		return true;
	end
	log("debug", "%s sent private message stanza to %s (%s)", from, to, o_data.jid);
	stanza:tag("x", { xmlns = "http://jabber.org/protocol/muc#user" }):up();
	stanza.attr.from = current_nick;
	self:route_to_occupant(o_data, stanza)
	stanza.attr.from = from;
	return true;
end

function room_mt:send_form(origin, stanza)
	origin.send(st.reply(stanza):query("http://jabber.org/protocol/muc#owner")
		:add_child(self:get_form_layout(stanza.attr.from):form())
	);
end

function room_mt:get_form_layout(actor)
	local whois = self:get_whois()
	local form = dataform.new({
		title = "Configuration for "..self.jid,
		instructions = "Complete and submit this form to configure the room.",
		{
			name = 'FORM_TYPE',
			type = 'hidden',
			value = 'http://jabber.org/protocol/muc#roomconfig'
		},
		{
			name = 'muc#roomconfig_roomname',
			type = 'text-single',
			label = 'Name',
			value = self:get_name() or "",
		},
		{
			name = 'muc#roomconfig_roomdesc',
			type = 'text-single',
			label = 'Description',
			value = self:get_description() or "",
		},
		{
			name = 'muc#roomconfig_persistentroom',
			type = 'boolean',
			label = 'Make Room Persistent?',
			value = self:get_persistent()
		},
		{
			name = 'muc#roomconfig_publicroom',
			type = 'boolean',
			label = 'Make Room Publicly Searchable?',
			value = not self:get_hidden()
		},
		{
			name = 'muc#roomconfig_changesubject',
			type = 'boolean',
			label = 'Allow Occupants to Change Subject?',
			value = self:get_changesubject()
		},
		{
			name = 'muc#roomconfig_whois',
			type = 'list-single',
			label = 'Who May Discover Real JIDs?',
			value = {
				{ value = 'moderators', label = 'Moderators Only', default = whois == 'moderators' },
				{ value = 'anyone',     label = 'Anyone',          default = whois == 'anyone' }
			}
		},
		{
			name = 'muc#roomconfig_roomsecret',
			type = 'text-private',
			label = 'Password',
			value = self:get_password() or "",
		},
		{
			name = 'muc#roomconfig_moderatedroom',
			type = 'boolean',
			label = 'Make Room Moderated?',
			value = self:get_moderated()
		},
		{
			name = 'muc#roomconfig_membersonly',
			type = 'boolean',
			label = 'Make Room Members-Only?',
			value = self:get_members_only()
		},
		{
			name = 'muc#roomconfig_historylength',
			type = 'text-single',
			label = 'Maximum Number of History Messages Returned by Room',
			value = tostring(self:get_historylength())
		}
	});
	return module:fire_event("muc-config-form", { room = self, actor = actor, form = form }) or form;
end

function room_mt:process_form(origin, stanza)
	local query = stanza.tags[1];
	local form = query:get_child("x", "jabber:x:data")
	if not form then origin.send(st.error_reply(stanza, "cancel", "service-unavailable")); return; end
	if form.attr.type == "cancel" then origin.send(st.reply(stanza)); return; end
	if form.attr.type ~= "submit" then origin.send(st.error_reply(stanza, "cancel", "bad-request", "Not a submitted form")); return; end

	local fields = self:get_form_layout(stanza.attr.from):data(form);
	if fields.FORM_TYPE ~= "http://jabber.org/protocol/muc#roomconfig" then origin.send(st.error_reply(stanza, "cancel", "bad-request", "Form is not of type room configuration")); return; end


	local changed = {};

	local function handle_option(name, field, allowed)
		local new = fields[field];
		if new == nil then return; end
		if allowed and not allowed[new] then return; end
		if new == self["get_"..name](self) then return; end
		changed[name] = true;
		self["set_"..name](self, new);
	end

	local event = { room = self, fields = fields, changed = changed, stanza = stanza, origin = origin, update_option = handle_option };
	module:fire_event("muc-config-submitted", event);

	handle_option("name", "muc#roomconfig_roomname");
	handle_option("description", "muc#roomconfig_roomdesc");
	handle_option("persistent", "muc#roomconfig_persistentroom");
	handle_option("moderated", "muc#roomconfig_moderatedroom");
	handle_option("members_only", "muc#roomconfig_membersonly");
	handle_option("public", "muc#roomconfig_publicroom");
	handle_option("changesubject", "muc#roomconfig_changesubject");
	handle_option("historylength", "muc#roomconfig_historylength");
	handle_option("whois", "muc#roomconfig_whois", valid_whois);
	handle_option("password", "muc#roomconfig_roomsecret");

	if self.save then self:save(true); end
	if self:is_locked() then
		self:unlock();
	end
	origin.send(st.reply(stanza));

	if next(changed) then
		local msg = st.message({type='groupchat', from=self.jid})
			:tag('x', {xmlns='http://jabber.org/protocol/muc#user'}):up()
				:tag('status', {code = '104'}):up();
		if changed.whois then
			local code = (self:get_whois() == 'moderators') and "173" or "172";
			msg.tags[1]:tag('status', {code = code}):up();
		end
		self:broadcast_message(msg, false)
	end
end

function room_mt:destroy(newjid, reason, password)
	local pr = st.presence({type = "unavailable"})
		:tag("x", {xmlns = "http://jabber.org/protocol/muc#user"})
			:tag("item", { affiliation='none', role='none' }):up()
			:tag("destroy", {jid=newjid})
	if reason then pr:tag("reason"):text(reason):up(); end
	if password then pr:tag("password"):text(password):up(); end
	for nick, occupant in pairs(self._occupants) do
		pr.attr.from = nick;
		for jid in pairs(occupant.sessions) do
			pr.attr.to = jid;
			self:_route_stanza(pr);
			self._jid_nick[jid] = nil;
		end
		self._occupants[nick] = nil;
		module:fire_event("muc-occupant-left", { room = self; nick = nick; });
	end
	self:set_persistent(false);
	module:fire_event("muc-room-destroyed", { room = self });
end

function room_mt:handle_disco_info_get_query(origin, stanza)
	origin.send(self:get_disco_info(stanza));
	return true;
end

function room_mt:handle_disco_items_get_query(origin, stanza)
	origin.send(self:get_disco_items(stanza));
	return true;
end

function room_mt:handle_admin_query_set_command(origin, stanza)
	local item = stanza.tags[1].tags[1];
	if item.attr.jid then -- Validate provided JID
		item.attr.jid = jid_prep(item.attr.jid);
		if not item.attr.jid then
			origin.send(st.error_reply(stanza, "modify", "jid-malformed"));
			return true;
		end
	end
	if not item.attr.jid and item.attr.nick then -- COMPAT Workaround for Miranda sending 'nick' instead of 'jid' when changing affiliation
		local occupant = self._occupants[self.jid.."/"..item.attr.nick];
		if occupant then item.attr.jid = occupant.jid; end
	elseif not item.attr.nick and item.attr.jid then
		local nick = self:get_occupant_jid(item.attr.jid);
		if nick then item.attr.nick = select(3, jid_split(nick)); end
	end
	local actor = stanza.attr.from;
	local callback = function() origin.send(st.reply(stanza)); end
	local reason = item:get_child_text("reason");
	if item.attr.affiliation and item.attr.jid and not item.attr.role then
		local success, errtype, err = self:set_affiliation(actor, item.attr.jid, item.attr.affiliation, callback, reason);
		if not success then origin.send(st.error_reply(stanza, errtype, err)); end
		return true;
	elseif item.attr.role and item.attr.nick and not item.attr.affiliation then
		local success, errtype, err = self:set_role(actor, self.jid.."/"..item.attr.nick, item.attr.role, callback, reason);
		if not success then origin.send(st.error_reply(stanza, errtype, err)); end
		return true;
	else
		origin.send(st.error_reply(stanza, "cancel", "bad-request"));
		return true;
	end
end

function room_mt:handle_admin_query_get_command(origin, stanza)
	local actor = stanza.attr.from;
	local affiliation = self:get_affiliation(actor);
	local item = stanza.tags[1].tags[1];
	local _aff = item.attr.affiliation;
	local _rol = item.attr.role;
	if _aff and not _rol then
		if affiliation == "owner" or (affiliation == "admin" and _aff ~= "owner" and _aff ~= "admin") then
			local reply = st.reply(stanza):query("http://jabber.org/protocol/muc#admin");
			for jid, affiliation in pairs(self._affiliations) do
				if affiliation == _aff then
					reply:tag("item", {affiliation = _aff, jid = jid}):up();
				end
			end
			origin.send(reply);
			return true;
		else
			origin.send(st.error_reply(stanza, "auth", "forbidden"));
			return true;
		end
	elseif _rol and not _aff then
		local role = self:get_role(self:get_occupant_jid(actor)) or self:get_default_role(affiliation);
		if role == "moderator" then
			if _rol == "none" then _rol = nil; end
			local reply = st.reply(stanza):query("http://jabber.org/protocol/muc#admin");
			for occupant_jid, occupant in pairs(self._occupants) do
				if occupant.role == _rol then
					reply:tag("item", {
						nick = select(3, jid_split(occupant_jid)),
						role = _rol or "none",
						affiliation = occupant.affiliation or "none",
						jid = occupant.jid
						}):up();
				end
			end
			origin.send(reply);
			return true;
		else
			origin.send(st.error_reply(stanza, "auth", "forbidden"));
			return true;
		end
	else
		origin.send(st.error_reply(stanza, "cancel", "bad-request"));
		return true;
	end
end

function room_mt:handle_owner_query_get_to_room(origin, stanza)
	if self:get_affiliation(stanza.attr.from) ~= "owner" then
		origin.send(st.error_reply(stanza, "auth", "forbidden", "Only owners can configure rooms"));
		return true;
	end

	self:send_form(origin, stanza);
	return true;
end
function room_mt:handle_owner_query_set_to_room(origin, stanza)
	if self:get_affiliation(stanza.attr.from) ~= "owner" then
		origin.send(st.error_reply(stanza, "auth", "forbidden", "Only owners can configure rooms"));
		return true;
	end

	local child = stanza.tags[1].tags[1];
	if not child then
		origin.send(st.error_reply(stanza, "modify", "bad-request"));
		return true;
	elseif child.name == "destroy" then
		local newjid = child.attr.jid;
		local reason = child:get_child_text("reason");
		local password = child:get_child_text("password");
		self:destroy(newjid, reason, password);
		origin.send(st.reply(stanza));
		return true;
	else
		self:process_form(origin, stanza);
		return true;
	end
end

function room_mt:handle_groupchat_to_room(origin, stanza)
	local from = stanza.attr.from;
	local current_nick = self:get_occupant_jid(from);
	local occupant = self._occupants[current_nick];
	if not occupant then -- not in room
		origin.send(st.error_reply(stanza, "cancel", "not-acceptable"));
		return true;
	elseif occupant.role == "visitor" then
		origin.send(st.error_reply(stanza, "auth", "forbidden"));
		return true;
	else
		local from = stanza.attr.from;
		stanza.attr.from = current_nick;
		local subject = stanza:get_child_text("subject");
		if subject then
			if occupant.role == "moderator" or
				( self:get_changesubject() and occupant.role == "participant" ) then -- and participant
				self:set_subject(current_nick, subject);
			else
				stanza.attr.from = from;
				origin.send(st.error_reply(stanza, "auth", "forbidden"));
			end
		else
			self:broadcast_message(stanza, self:get_historylength() > 0 and stanza:get_child("body"));
		end
		stanza.attr.from = from;
		return true;
	end
end

-- hack - some buggy clients send presence updates to the room rather than their nick
function room_mt:handle_presence_to_room(origin, stanza)
	local current_nick = self:get_occupant_jid(stanza.attr.from);
	local handled
	if current_nick then
		local to = stanza.attr.to;
		stanza.attr.to = current_nick;
		handled = self:handle_presence_to_occupant(origin, stanza);
		stanza.attr.to = to;
	end
	return handled;
end

function room_mt:handle_mediated_invite(origin, stanza)
	local payload = stanza:get_child("x", "http://jabber.org/protocol/muc#user"):get_child("invite")
	local _from, _to = stanza.attr.from, stanza.attr.to;
	local current_nick = self:get_occupant_jid(_from)
	-- Need visitor role or higher to invite
	if not self:get_role(current_nick) or not self:get_default_role(self:get_affiliation(_from)) then
		origin.send(st.error_reply(stanza, "auth", "forbidden"));
		return true;
	end
	local _invitee = jid_prep(payload.attr.to);
	if _invitee then
		if self:get_whois() == "moderators" then
			_from = current_nick;
		end
		local _reason = payload:get_child_text("reason")
		local invite = st.message({from = _to, to = _invitee, id = stanza.attr.id})
			:tag('x', {xmlns='http://jabber.org/protocol/muc#user'})
				:tag('invite', {from=_from})
					:tag('reason'):text(_reason or ""):up()
				:up();
		local password = self:get_password()
		if password then
			invite:tag("password"):text(password):up();
		end
			invite:up()
			:tag('x', {xmlns="jabber:x:conference", jid=_to}) -- COMPAT: Some older clients expect this
				:text(_reason or "")
			:up()
			:tag('body') -- Add a plain message for clients which don't support invites
				:text(_from..' invited you to the room '.._to..(_reason and (' ('.._reason..')') or ""))
			:up();
		module:fire_event("muc-invite", { room = self, stanza = invite, origin = origin, incoming = stanza });
		return true;
	else
		origin.send(st.error_reply(stanza, "cancel", "jid-malformed"));
		return true;
	end
end

module:hook("muc-invite", function(event)
	event.room:_route_stanza(event.stanza);
	return true;
end, -1)

-- When an invite is sent; add an affiliation for the invitee
module:hook("muc-invite", function(event)
	local room, stanza = event.room, event.stanza
	local invitee = stanza.attr.to
	if room:get_members_only() and not room:get_affiliation(invitee) then
		local from = stanza:get_child("x", "http://jabber.org/protocol/muc#user"):get_child("invite").attr.from
		local current_nick = room:get_occupant_jid(from)
		log("debug", "%s invited %s into members only room %s, granting membership", from, invitee, room.jid);
		room:set_affiliation(from, invitee, "member", nil, "Invited by " .. current_nick)
	end
end)

function room_mt:handle_mediated_decline(origin, stanza)
	local payload = stanza:get_child("x", "http://jabber.org/protocol/muc#user"):get_child("decline")
	local declinee = jid_prep(payload.attr.to);
	if declinee then
		local from, to = stanza.attr.from, stanza.attr.to;
		-- TODO: Validate declinee
		local reason = payload:get_child_text("reason")
		local decline = st.message({from = to, to = declinee, id = stanza.attr.id})
			:tag('x', {xmlns='http://jabber.org/protocol/muc#user'})
				:tag('decline', {from=from})
					:tag('reason'):text(reason or ""):up()
				:up()
			:up()
			:tag('body') -- Add a plain message for clients which don't support declines
				:text(from..' declined your invite to the room '..to..(reason and (' ('..reason..')') or ""))
			:up();
		module:fire_event("muc-decline", { room = self, stanza = decline, origin = origin, incoming = stanza });
		return true;
	else
		origin.send(st.error_reply(stanza, "cancel", "jid-malformed"));
		return true;
	end
end

module:hook("muc-decline", function(event)
	local room, stanza = event.room, event.stanza
	local occupant = room:get_occupant_by_real_jid(stanza.attr.to);
	if occupant then
		room:route_to_occupant(occupant, stanza)
	else
		room:route_stanza(stanza);
	end
	return true;
end, -1)

function room_mt:handle_message_to_room(origin, stanza)
	local type = stanza.attr.type;
	if type == "groupchat" then
		return self:handle_groupchat_to_room(origin, stanza)
	elseif type == "error" and is_kickable_error(stanza) then
		return self:handle_kickable(origin, stanza)
	elseif type == nil then
		local x = stanza:get_child("x", "http://jabber.org/protocol/muc#user");
		if x then
			local payload = x.tags[1];
			if payload == nil then
				-- fallthrough
			elseif payload.name == "invite" and payload.attr.to then
				return self:handle_mediated_invite(origin, stanza)
			elseif payload.name == "decline" and payload.attr.to then
				return self:handle_mediated_decline(origin, stanza)
			end
			origin.send(st.error_reply(stanza, "cancel", "bad-request"));
			return true;
		end
	else
		return nil;
	end
end

function room_mt:route_stanza(stanza)
	module:send(stanza)
end

function room_mt:get_affiliation(jid)
	local node, host, resource = jid_split(jid);
	local bare = node and node.."@"..host or host;
	local result = self._affiliations[bare]; -- Affiliations are granted, revoked, and maintained based on the user's bare JID.
	if not result and self._affiliations[host] == "outcast" then result = "outcast"; end -- host banned
	return result;
end
function room_mt:set_affiliation(actor, jid, affiliation, callback, reason)
	jid = jid_bare(jid);
	if affiliation == "none" then affiliation = nil; end
	if affiliation and affiliation ~= "outcast" and affiliation ~= "owner" and affiliation ~= "admin" and affiliation ~= "member" then
		return nil, "modify", "not-acceptable";
	end
	if actor ~= true then
		local actor_affiliation = self:get_affiliation(actor);
		local target_affiliation = self:get_affiliation(jid);
		if target_affiliation == affiliation then -- no change, shortcut
			if callback then callback(); end
			return true;
		end
		if actor_affiliation ~= "owner" then
			if affiliation == "owner" or affiliation == "admin" or actor_affiliation ~= "admin" or target_affiliation == "owner" or target_affiliation == "admin" then
				return nil, "cancel", "not-allowed";
			end
		elseif target_affiliation == "owner" and jid_bare(actor) == jid then -- self change
			local is_last = true;
			for j, aff in pairs(self._affiliations) do if j ~= jid and aff == "owner" then is_last = false; break; end end
			if is_last then
				return nil, "cancel", "conflict";
			end
		end
	end
	self._affiliations[jid] = affiliation;
	local role = self:get_default_role(affiliation);
	local x = st.stanza("x", {xmlns = "http://jabber.org/protocol/muc#user"})
			:tag("item", {affiliation=affiliation or "none", role=role or "none"})
				:tag("reason"):text(reason or ""):up()
			:up();
	local presence_type = nil;
	if not role then -- getting kicked
		presence_type = "unavailable";
		if affiliation == "outcast" then
			x:tag("status", {code="301"}):up(); -- banned
		else
			x:tag("status", {code="321"}):up(); -- affiliation change
		end
	end
	local modified_nicks = {};
	for nick, occupant in pairs(self._occupants) do
		if jid_bare(occupant.jid) == jid then
			if not role then -- getting kicked
				self._occupants[nick] = nil;
			else
				occupant.affiliation, occupant.role = affiliation, role;
			end
			for jid,pres in pairs(occupant.sessions) do -- remove for all sessions of the nick
				if not role then self._jid_nick[jid] = nil; end
				local p = st.clone(pres);
				p.attr.from = nick;
				p.attr.type = presence_type;
				p.attr.to = jid;
				p:add_child(x);
				self:_route_stanza(p);
				if occupant.jid == jid then
					modified_nicks[nick] = p;
				end
			end
		end
	end
	if self.save then self:save(); end
	if callback then callback(); end
	for nick,p in pairs(modified_nicks) do
		p.attr.from = nick;
		self:broadcast_except_nick(p, nick);
	end
	return true;
end

function room_mt:get_role(nick)
	local session = self._occupants[nick];
	return session and session.role or nil;
end
function room_mt:can_set_role(actor_jid, occupant_jid, role)
	local occupant = self._occupants[occupant_jid];
	if not occupant or not actor_jid then return nil, "modify", "not-acceptable"; end

	if actor_jid == true then return true; end

	local actor = self._occupants[self:get_occupant_jid(actor_jid)];
	if actor and actor.role == "moderator" then
		if occupant.affiliation ~= "owner" and occupant.affiliation ~= "admin" then
			if actor.affiliation == "owner" or actor.affiliation == "admin" then
				return true;
			elseif occupant.role ~= "moderator" and role ~= "moderator" then
				return true;
			end
		end
	end
	return nil, "cancel", "not-allowed";
end
function room_mt:set_role(actor, occupant_jid, role, callback, reason)
	if role == "none" then role = nil; end
	if role and role ~= "moderator" and role ~= "participant" and role ~= "visitor" then return nil, "modify", "not-acceptable"; end
	local allowed, err_type, err_condition = self:can_set_role(actor, occupant_jid, role);
	if not allowed then return allowed, err_type, err_condition; end
	local occupant = self._occupants[occupant_jid];
	local x = st.stanza("x", {xmlns = "http://jabber.org/protocol/muc#user"})
			:tag("item", {affiliation=occupant.affiliation or "none", nick=select(3, jid_split(occupant_jid)), role=role or "none"})
				:tag("reason"):text(reason or ""):up()
			:up();
	local presence_type = nil;
	if not role then -- kick
		presence_type = "unavailable";
		self._occupants[occupant_jid] = nil;
		for jid in pairs(occupant.sessions) do -- remove for all sessions of the nick
			self._jid_nick[jid] = nil;
		end
		x:tag("status", {code = "307"}):up();
	else
		occupant.role = role;
	end
	local bp;
	for jid,pres in pairs(occupant.sessions) do -- send to all sessions of the nick
		local p = st.clone(pres);
		p.attr.from = occupant_jid;
		p.attr.type = presence_type;
		p.attr.to = jid;
		p:add_child(x);
		self:_route_stanza(p);
		if occupant.jid == jid then
			bp = p;
		end
	end
	if callback then callback(); end
	if bp then
		self:broadcast_except_nick(bp, occupant_jid);
	end
	return true;
end

function room_mt:_route_stanza(stanza)
	local muc_child;
	if stanza.name == "presence" then
		local to_occupant = self._occupants[self:get_occupant_jid(stanza.attr.to)];
		local from_occupant = self._occupants[stanza.attr.from];
		if to_occupant and from_occupant then
			if self:get_whois() == 'anyone' then
			    muc_child = stanza:get_child("x", "http://jabber.org/protocol/muc#user");
			else
				if to_occupant.role == "moderator" or jid_bare(to_occupant.jid) == jid_bare(from_occupant.jid) then
					muc_child = stanza:get_child("x", "http://jabber.org/protocol/muc#user");
				end
			end
		end
		if muc_child then
			for item in muc_child:childtags("item") do
				if from_occupant == to_occupant then
					item.attr.jid = stanza.attr.to;
				else
					item.attr.jid = from_occupant.jid;
				end
			end
		end
	end
	self:route_stanza(stanza);
	if muc_child then
		for item in muc_child:childtags("item") do
			item.attr.jid = nil;
		end
	end
end

local _M = {}; -- module "muc"

function _M.new_room(jid, config)
	return setmetatable({
		jid = jid;
		locked = nil;
		_jid_nick = {};
		_occupants = {};
		_data = {
		    whois = 'moderators';
		    history_length = math.min((config and config.history_length)
		    	or default_history_length, max_history_length);
		};
		_affiliations = {};
	}, room_mt);
end

function _M.set_max_history_length(_max_history_length)
	max_history_length = _max_history_length or math.huge;
end

_M.room_mt = room_mt;

return _M;