local jid_bare = require "util.jid".bare;

local jid_resource = require "util.jid".resource;

local resourceprep = require "util.encodings".stringprep.resourceprep;

local st = require "util.stanza";

local dataforms = require "util.dataforms";

local allow_unaffiliated = module:get_option_boolean("allow_unaffiliated_register", false);

local enforce_nick = module:get_option_boolean("enforce_registered_nickname", false);

-- reserved_nicks[nick] = jid

local function get_reserved_nicks(room)

	if room._reserved_nicks then

		return room._reserved_nicks;

	end

	module:log("debug", "Refreshing reserved nicks...");

	local reserved_nicks = {};

	for jid in room:each_affiliation() do

		local data = room._affiliation_data[jid];

		local nick = data and data.reserved_nickname;

		module:log("debug", "Refreshed for %s: %s", jid, nick);

		if nick then

			reserved_nicks[nick] = jid;

		end

	end

	room._reserved_nicks = reserved_nicks;

	return reserved_nicks;

end

-- Returns the registered nick, if any, for a JID

-- Note: this is just the *nick* part, i.e. the resource of the in-room JID

local function get_registered_nick(room, jid)

	local registered_data = room._affiliation_data[jid];

	if not registered_data then

		return;

	end

	return registered_data.reserved_nickname;

end

-- Returns the JID, if any, that registered a nick (not in-room JID)

local function get_registered_jid(room, nick)

	local reserved_nicks = get_reserved_nicks(room);

	return reserved_nicks[nick];

end

module:hook("muc-set-affiliation", function (event)

	-- Clear reserved nick cache

	event.room._reserved_nicks = nil;

end);

module:add_feature("jabber:iq:register");

module:hook("muc-disco#info", function (event)

	event.reply:tag("feature", { var = "jabber:iq:register" }):up();

end);

local registration_form = dataforms.new {

	{ name = "FORM_TYPE", type = "hidden", value = "http://jabber.org/protocol/muc#register" },

	{ name = "muc#register_roomnick", type = "text-single", label = "Nickname"},

};

local function enforce_nick_policy(event)

	local origin, stanza = event.origin, event.stanza;

	local room = assert(event.room); -- FIXME

	if not room then return; end

	-- Check if the chosen nickname is reserved

	local requested_nick = jid_resource(stanza.attr.to);

	local reserved_by = get_registered_jid(room, requested_nick);

	if reserved_by and reserved_by ~= jid_bare(stanza.attr.from) then

		module:log("debug", "%s attempted to use nick %s reserved by %s", stanza.attr.from, requested_nick, reserved_by);

		local reply = st.error_reply(stanza, "cancel", "conflict"):up();

		origin.send(reply:tag("x", {xmlns = "http://jabber.org/protocol/muc"}));

		return true;

	end

	-- Check if the occupant has a reservation they must use

	if enforce_nick then

		local nick = get_registered_nick(room, jid_bare(stanza.attr.from));

		if nick then

			if event.occupant then

				event.occupant.nick = jid_bare(event.occupant.nick) .. "/" .. nick;

			elseif event.dest_occupant.nick ~= jid_bare(event.dest_occupant.nick) .. "/" .. nick then

				module:log("debug", "Attempt by %s to join as %s, but their reserved nick is %s", stanza.attr.from, requested_nick, nick);

				local reply = st.error_reply(stanza, "cancel", "not-acceptable"):up();

				origin.send(reply:tag("x", {xmlns = "http://jabber.org/protocol/muc"}));

				return true;

			end

		end

	end

end

module:hook("muc-occupant-pre-join", enforce_nick_policy);

module:hook("muc-occupant-pre-change", enforce_nick_policy);

-- Discovering Reserved Room Nickname

-- http://xmpp.org/extensions/xep-0045.html#reservednick

module:hook("muc-disco#info/x-roomuser-item", function (event)

	local nick = get_registered_nick(event.room, jid_bare(event.stanza.attr.from));

	if nick then

		event.reply:tag("identity", { category = "conference", type = "text", name = nick })

	end

end);

local function handle_register_iq(room, origin, stanza)

	local user_jid = jid_bare(stanza.attr.from)

	local affiliation = room:get_affiliation(user_jid);

	if affiliation == "outcast" then

		origin.send(st.error_reply(stanza, "auth", "forbidden"));

		return true;

	elseif not (affiliation or allow_unaffiliated) then

		origin.send(st.error_reply(stanza, "auth", "registration-required"));

		return true;

	end

	local reply = st.reply(stanza);

	local registered_nick = get_registered_nick(room, user_jid);

	if stanza.attr.type == "get" then

		reply:query("jabber:iq:register");

		if registered_nick then

			reply:tag("registered"):up();

			reply:tag("username"):text(registered_nick);

			origin.send(reply);

			return true;

		end

		reply:add_child(registration_form:form());

	else -- type == set -- handle registration form

		local query = stanza.tags[1];

		if query:get_child("remove") then

			-- Remove "member" affiliation, but preserve if any other

			local new_affiliation = affiliation ~= "member" and affiliation;

			local ok, err_type, err_condition = room:set_affiliation(true, user_jid, new_affiliation, nil, false);

			if not ok then

				origin.send(st.error_reply(stanza, err_type, err_condition));

				return true;

			end

			origin.send(reply);

			return true;

		end

		local form_tag = query:get_child("x", "jabber:x:data");

		local reg_data = form_tag and registration_form:data(form_tag);

		if not reg_data then

			origin.send(st.error_reply(stanza, "modify", "bad-request", "Error in form"));

			return true;

		end

		-- Is the nickname valid?

		local desired_nick = resourceprep(reg_data["muc#register_roomnick"]);

		if not desired_nick then

			origin.send(st.error_reply(stanza, "modify", "bad-request", "Invalid Nickname"));

			return true;

		end

		-- Is the nickname currently in use by another user?

		local current_occupant = room:get_occupant_by_nick(room.jid.."/"..desired_nick);

		if current_occupant and current_occupant.bare_jid ~= user_jid then

			origin.send(st.error_reply(stanza, "cancel", "conflict"));

			return true;

		end

		-- Is the nickname currently reserved by another user?

		local reserved_by = get_registered_jid(room, desired_nick);

		if reserved_by and reserved_by ~= user_jid then

			origin.send(st.error_reply(stanza, "cancel", "conflict"));

			return true;

		end

		-- Kick any sessions that are not using this nick before we register it

		if enforce_nick then

			local required_room_nick = room.jid.."/"..desired_nick;

			for room_nick, occupant in room:each_occupant() do

				if occupant.bare_jid == user_jid and room_nick ~= required_room_nick then

					room:set_role(true, room_nick, nil); -- Kick (TODO: would be nice to use 333 code)

				end

			end

		end

		-- Checks passed, save the registration

		if registered_nick ~= desired_nick then

			local registration_data = { reserved_nickname = desired_nick };

			local ok, err_type, err_condition = room:set_affiliation(true, user_jid, "member", nil, registration_data);

			if not ok then

				origin.send(st.error_reply(stanza, err_type, err_condition));

				return true;

			end

			module:log("debug", "Saved nick registration for %s: %s", user_jid, desired_nick);

			origin.send(reply);

			return true;

		end

	end

	origin.send(reply);

	return true;

end

return {

	get_registered_nick = get_registered_nick;

	get_registered_jid = get_registered_jid;

	handle_register_iq = handle_register_iq;

}