# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1566758803 -7200
# Node ID 3e0f4d72782549730478ac11b6d66e3e07edbcf4
# Parent  d7b589dec591089e064143e0d3be4831ed13d549
mod_vcard_muc: Add an alternative method of signaling avatar change

When the avatar has been changed, a signal is sent that the room
configuration has changed. Clients then do a disco#info query to find
the SHA-1 of the new avatar. They can then fetch it as before, or not if
they have it cached already.

This is meant to be less disruptive than signaling via presence, which
caused problems for some clients.

If clients transition to the new method, the old one can eventually be removed.

The namespace is made up while waiting for standardization.

Otherwise it is very close to what's described in
https://xmpp.org/extensions/inbox/muc-avatars.html

diff -r d7b589dec591 -r 3e0f4d727825 mod_vcard_muc/mod_vcard_muc.lua
--- a/mod_vcard_muc/mod_vcard_muc.lua	Fri Aug 23 23:01:16 2019 +0200
+++ b/mod_vcard_muc/mod_vcard_muc.lua	Sun Aug 25 20:46:43 2019 +0200
@@ -42,7 +42,7 @@
 local function broadcast_presence(room_jid, to)
 	local room = get_room_from_jid(room_jid);
 
-	local photo_hash = get_photo_hash(room)
+	local photo_hash = get_photo_hash(room);
 	local presence_vcard = st.presence({to = to, from = room_jid})
 		:tag("x", { xmlns = "vcard-temp:x:update" })
 			:tag("photo"):text(photo_hash):up();
@@ -78,6 +78,10 @@
 			if vcards:set(room_node, st.preserialize(stanza.tags[1])) then
 				session.send(st.reply(stanza):tag("vCard", { xmlns = "vcard-temp" }));
 				broadcast_presence(room_jid, nil)
+
+				room:broadcast_message(st.message({ from = room.jid, type = "groupchat" })
+					:tag("x", { xmlns = "http://jabber.org/protocol/muc#user" })
+						:tag("status", { code = "104" }));
 			else
 				-- TODO unable to write file, file may be locked, etc, what's the correct error?
 				session.send(st.error_reply(stanza, "wait", "internal-server-error"));
@@ -95,6 +99,12 @@
 
 module:hook("muc-disco#info", function(event)
 	event.reply:tag("feature", { var = "vcard-temp" }):up();
+
+	table.insert(event.form, {
+			name = "{http://modules.prosody.im/mod_vcard_muc}avatar#sha1",
+			type = "text-single",
+		});
+	event.formdata["{http://modules.prosody.im/mod_vcard_muc}avatar#sha1"] = get_photo_hash(event.room);
 end);
 
 module:hook("muc-occupant-session-new", function(event)