1 files changed, 99 insertions, 0 deletions
diff --git a/plugins/muc/subject.lib.lua b/plugins/muc/subject.lib.lua
new file mode 100644
index 00000000..8f5f9231
--- /dev/null
+++ b/plugins/muc/subject.lib.lua
@@ -0,0 +1,99 @@
+-- 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 st = require "util.stanza";
+
+local muc_util = module:require "muc/util";
+local valid_roles = muc_util.valid_roles;
+
+local function create_subject_message(from, subject)
+	return st.message({from = from; type = "groupchat"})
+		:tag("subject"):text(subject):up();
+end
+
+local function get_changesubject(room)
+	return room._data.changesubject;
+end
+
+local function set_changesubject(room, changesubject)
+	changesubject = changesubject and true or nil;
+	if get_changesubject(room) == changesubject then return false; end
+	room._data.changesubject = changesubject;
+	return true;
+end
+
+module:hook("muc-config-form", function(event)
+	table.insert(event.form, {
+		name = "muc#roomconfig_changesubject";
+		type = "boolean";
+		label = "Allow Occupants to Change Subject?";
+		value = get_changesubject(event.room);
+	});
+end);
+
+module:hook("muc-config-submitted/muc#roomconfig_changesubject", function(event)
+	if set_changesubject(event.room, event.value) then
+		event.status_codes["104"] = true;
+	end
+end);
+
+local function get_subject(room)
+	-- a <message/> stanza from the room JID (or from the occupant JID of the entity that set the subject)
+	return room._data.subject_from or room.jid, room._data.subject;
+end
+
+local function send_subject(room, to)
+	local msg = create_subject_message(get_subject(room));
+	msg.attr.to = to;
+	room:route_stanza(msg);
+end
+
+local function set_subject(room, from, subject)
+	if subject == "" then subject = nil; end
+	local old_from, old_subject = get_subject(room);
+	if old_subject == subject and old_from == from then return false; end
+	room._data.subject_from = from;
+	room._data.subject = subject;
+	local msg = create_subject_message(from, subject);
+	room:broadcast_message(msg);
+	return true;
+end
+
+-- Send subject to joining user
+module:hook("muc-occupant-session-new", function(event)
+	send_subject(event.room, event.stanza.attr.from);
+end, 20);
+
+-- Prosody has made the decision that messages with <subject/> are exclusively subject changes
+-- e.g. body will be ignored; even if the subject change was not allowed
+module:hook("muc-occupant-groupchat", function(event)
+	local stanza = event.stanza;
+	local subject = stanza:get_child("subject");
+	if subject then
+		local occupant = event.occupant;
+		-- Role check for subject changes
+		local role_rank = valid_roles[occupant and occupant.role or "none"];
+		if role_rank >= valid_roles.moderator or
+			( role_rank >= valid_roles.participant and get_changesubject(event.room) ) then -- and participant
+			set_subject(event.room, occupant.nick, subject:get_text());
+			return true;
+		else
+			event.origin.send(st.error_reply(stanza, "auth", "forbidden"));
+			return true;
+		end
+	end
+end, 20);
+
+return {
+	get_changesubject = get_changesubject;
+	set_changesubject = set_changesubject;
+	get = get_subject;
+	set = set_subject;
+	send = send_subject;
+};