--- a/mod_smacks/mod_smacks.lua	Sat Mar 05 18:52:43 2011 +0000
+++ b/mod_smacks/mod_smacks.lua	Fri Mar 18 21:26:27 2011 +0000
@@ -1,18 +1,23 @@
 local st = require "util.stanza";
+local uuid_generate = require "util.uuid".generate;
 
 local t_insert, t_remove = table.insert, table.remove;
 local math_min = math.min;
+local os_time = os.time;
 local tonumber, tostring = tonumber, tostring;
 local add_filter = require "util.filters".add_filter;
 local timer = require "util.timer";
 
 local xmlns_sm = "urn:xmpp:sm:2";
+local xmlns_errors = "urn:ietf:params:xml:ns:xmpp-stanzas";
 
 local sm_attr = { xmlns = xmlns_sm };
 
-local resume_timeout = 300;
+local resume_timeout = module:get_option("smacks_hibernation_time", 300);
 local max_unacked_stanzas = 0;
 
+local session_registry = {};
+
 module:hook("stream-features",
 		function (event)
 			event.features:tag("sm", sm_attr):tag("optional"):up():up();
@@ -23,49 +28,74 @@
 			event.features:tag("sm", sm_attr):tag("optional"):up():up();
 		end);
 
-module:hook_stanza(xmlns_sm, "enable",
+module:hook_stanza("http://etherx.jabber.org/streams", "features",
 		function (session, stanza)
-			module:log("debug", "Enabling stream management");
-			session.smacks = true;
-			
-			-- Overwrite process_stanza() and send()
-			local queue = {};
-			session.outgoing_stanza_queue = queue;
-			session.last_acknowledged_stanza = 0;
-			local _send = session.sends2s or session.send;
-			local function new_send(stanza)
-				local attr = stanza.attr;
-				if attr and not attr.xmlns then -- Stanza in default stream namespace
-					queue[#queue+1] = st.clone(stanza);
-				end
-				local ok, err = _send(stanza);
-				if ok and #queue > max_unacked_stanzas and not session.awaiting_ack then
-					session.awaiting_ack = true;
-					return _send(st.stanza("r", { xmlns = xmlns_sm }));
-				end
-				return ok, err;
+			if not session.smacks and stanza:get_child("sm", xmlns_sm) then
+				session.send(st.stanza("enable", sm_attr));
 			end
-			
-			if session.sends2s then
-				session.sends2s = new_send;
-			else
-				session.send = new_send;
+end);
+
+local function wrap_session(session, resume)
+	-- Overwrite process_stanza() and send()
+	local queue;
+	if not resume then
+		queue = {};
+		session.outgoing_stanza_queue = queue;
+		session.last_acknowledged_stanza = 0;
+	else
+		queue = session.outgoing_stanza_queue;
+	end
+	
+	local _send = session.sends2s or session.send;
+	local function new_send(stanza)
+		local attr = stanza.attr;
+		if attr and not attr.xmlns then -- Stanza in default stream namespace
+			queue[#queue+1] = st.clone(stanza);
+		end
+		local ok, err = _send(stanza);
+		if ok and #queue > max_unacked_stanzas and not session.awaiting_ack then
+			session.awaiting_ack = true;
+			return _send(st.stanza("r", sm_attr));
+		end
+		return ok, err;
+	end
+	
+	if session.sends2s then
+		session.sends2s = new_send;
+	else
+		session.send = new_send;
+	end
+	
+	if not resume then
+		session.handled_stanza_count = 0;
+		add_filter(session, "stanzas/in", function (stanza)
+			if not stanza.attr.xmlns then
+				session.handled_stanza_count = session.handled_stanza_count + 1;
+				session.log("debug", "Handled %d incoming stanzas", session.handled_stanza_count);
 			end
-			
-			session.handled_stanza_count = 0;
-			add_filter(session, "stanzas/in", function (stanza)
-				if not stanza.attr.xmlns then
-					session.handled_stanza_count = session.handled_stanza_count + 1;
-					session.log("debug", "Handled %d incoming stanzas", session.handled_stanza_count);
-				end
-				return stanza;
-			end);
+			return stanza;
+		end);
+	end
+
+	return session;
+end
 
-			if not stanza.attr.resume then -- FIXME: Resumption should be a different spec :/
-				_send(st.stanza("enabled", sm_attr));
-				return true;
-			end
-		end, 100);
+module:hook_stanza(xmlns_sm, "enable", function (session, stanza)
+	module:log("debug", "Enabling stream management");
+	session.smacks = true;
+	
+	wrap_session(session);
+	
+	local resume_token;
+	local resume = stanza.attr.resume;
+	if resume == "true" or resume == "1" then
+		resume_token = uuid_generate();
+		session_registry[resume_token] = session;
+		session.resumption_token = resume_token;
+	end
+	session.send(st.stanza("enabled", { xmlns = xmlns_sm, id = resume_token, resume = resume }));
+	return true;
+end, 100);
 
 module:hook_stanza(xmlns_sm, "r", function (origin, stanza)
 	if not origin.smacks then
@@ -88,6 +118,7 @@
 	if handled_stanza_count > #queue then
 		module:log("warn", "The client says it handled %d new stanzas, but we only sent %d :)",
 			handled_stanza_count, #queue);
+		module:log("debug", "Client h: %d, our h: %d", tonumber(stanza.attr.h), origin.last_acknowledged_stanza);
 		for i=1,#queue do
 			module:log("debug", "Q item %d: %s", i, tostring(queue[i]));
 		end
@@ -134,11 +165,17 @@
 				handle_unacked_stanzas(session);
 			end
 		else
-			session.hibernating = true;
+			local hibernate_time = os_time(); -- Track the time we went into hibernation
+			session.hibernating = hibernate_time;
 			timer.add_task(resume_timeout, function ()
-				if session.hibernating then
+				-- Check the hibernate time still matches what we think it is,
+				-- otherwise the session resumed and re-hibernated.
+				if session.hibernating == hibernate_time then
+					session_registry[session.resumption_token] = nil;
 					session.resumption_token = nil;
-					sessionmanager.destroy_session(session); -- Re-destroy
+					-- This recursion back into our destroy handler is to
+					-- make sure we still handle any queued stanzas
+					sessionmanager.destroy_session(session);
 				end
 			end);
 			return; -- Postpone destruction for now
@@ -147,3 +184,60 @@
 	end
 	return _destroy_session(session, err);
 end
+
+module:hook_stanza(xmlns_sm, "resume", function (session, stanza)
+	local id = stanza.attr.previd;
+	local original_session = session_registry[id];
+	if not original_session then
+		session.send(st.stanza("failed", sm_attr)
+			:tag("item-not-found", { xmlns = xmlns_errors })
+		);
+	elseif session.username == original_session.username
+	and session.host == original_session.host then
+		-- TODO: All this should move to sessionmanager (e.g. session:replace(new_session))
+		original_session.ip = session.ip;
+		original_session.conn = session.conn;
+		original_session.send = session.send;
+		original_session.stream = session.stream;
+		original_session.secure = session.secure;
+		original_session.hibernating = nil;
+		local filter = original_session.filter;
+		local stream = session.stream;
+		local log = session.log;
+		function original_session.data(data)
+			data = filter("bytes/in", data);
+			if data then
+				local ok, err = stream:feed(data);
+				if ok then return; end
+				log("debug", "Received invalid XML (%s) %d bytes: %s", tostring(err), #data, data:sub(1, 300):gsub("[\r\n]+", " "):gsub("[%z\1-\31]", "_"));
+				original_session:close("xml-not-well-formed");
+			end
+		end
+		wrap_session(original_session, true);
+		-- Inform xmppstream of the new session (passed to its callbacks)
+		stream:set_session(original_session);
+		-- Similar for connlisteners
+		require "net.connlisteners".get("xmppclient").associate_session(session.conn, original_session);
+
+		session.send(st.stanza("resumed", { xmlns = xmlns_sm,
+			h = original_session.handled_stanza_count, previd = id }));
+		
+		-- Fake an <a> with the h of the <resume/> from the client
+		original_session:dispatch_stanza(st.stanza("a", { xmlns = xmlns_sm,
+			h = stanza.attr.h }));
+		
+		-- Ok, we need to re-send any stanzas that the client didn't see
+		-- ...they are what is now left in the outgoing stanza queue
+		local queue = original_session.outgoing_stanza_queue;
+		for i=1,#queue do
+			session.send(queue[i]);
+		end
+	else
+		log("warn", "Client %s@%s[%s] tried to resume stream for %s@%s[%s]",
+			session.username or "?", session.host or "?", session.type,
+			original_session.username or "?", original_session.host or "?", original_session.type);
+		session.send(st.stanza("failed", sm_attr)
+			:tag("not-authorized", { xmlns = xmlns_errors }));
+	end
+	return true;
+end);