local st = require "util.stanza";

local keepalive_servers = module:get_option_set("keepalive_servers");

local keepalive_interval = module:get_option_number("keepalive_interval", 60);

local host = module.host;

local function send_pings()

	for remote_domain, session in pairs(hosts[host].s2sout) do

		if session.type == "s2sout" -- as opposed to _unauthed

		and (not(keepalive_servers) or keepalive_servers:contains(remote_domain)) then

			session.sends2s(st.iq({ to = remote_domain, type = "get", from = host, id = "keepalive" })

				:tag("ping", { xmlns = "urn:xmpp:ping" })

			);

			-- Note: We don't actually check if this comes back.

		end

	end

	for session in pairs(prosody.incoming_s2s) do

		if session.type == "s2sin" -- as opposed to _unauthed

		and (not(keepalive_servers) or keepalive_servers:contains(session.from_host)) then

			session.sends2s " ";

			-- If the connection is dead, this should make it time out.

		end

	end

	return keepalive_interval;

end

if module.add_timer then -- 0.9

	module:add_timer(keepalive_interval, send_pings);

else -- 0.8

	local timer = require "util.timer";

	local unloaded;

	timer.add_task(keepalive_interval, function()

		if not unloaded then

			return send_pings()

		end

	end);

	function module.unload()

		unloaded = true

	end

end