--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_bind2/mod_bind2.lua	Sun Nov 28 19:45:25 2021 +0100
@@ -0,0 +1,51 @@
+local mm = require "core.modulemanager";
+local sm = require "core.sessionmanager";
+
+local xmlns_bind2 --[[<const>]] = "urn:xmpp:bind2:0";
+local xmlns_carbons --[[<const>]] = "urn:xmpp:carbons:2";
+
+module:depends("sasl2");
+module:depends("carbons");
+
+module:hook_tag(xmlns_sasl2, "authenticate", function (session, auth)
+	session.bind2 = auth:get_child("bind", xmlns_bind2);
+end, 1);
+
+module:hook("sasl2/c2s/success", function (event)
+	local session = event.session;
+	if not session.bind2 then return end
+
+	-- When it receives a bind 2.0 on an authenticated not-yet-bound session, the
+	-- server MUST:
+
+	-- Clear the offline messages for this user, if any, without sending them (as
+	-- they will be provided by MAM).
+	if mm.is_loaded(module.host, "offline") then
+		-- TODO
+	end
+
+	-- Perform resource binding to a random resource (see 6120)
+	if not sm.bind_resource(session, nil) then
+		-- FIXME How should this be handled even?
+		session:close("reset");
+		return true;
+	end
+
+	-- Work out which contacts have unread messages in the user's MAM archive,
+	-- how many, and what the id of the last read message is
+	-- XXX How do we know what the last read message was?
+	-- TODO archive:summary(session.username, { after = ??? });
+
+	-- Get the id of the newest stanza in the user's MAM archive
+	-- TODO archive:find(session.username, { reverse = true, limit = 1 });
+
+	-- Silently enable carbons for this session
+	session.carbons = xmlns_carbons;
+
+	-- After processing the bind stanza, as above, the server MUST respond with
+	-- an element of type 'bound' in the namespace 'urn:xmpp:bind2:0', as in the
+	-- below example
+	event.success:tag("bound", xmlns_bind2):text_tag("jid", session.full_jid):up();
+
+	session.bind2 = nil;
+end);