local pack = table.pack or require "util.table".pack;

local json = require "util.json";

local array = require "util.array";

local datetime = require "util.datetime".datetime;

local socket = require "socket";

module:set_global();

local function sink_maker(config)

	local send = function () end

	if config.filename then

		local logfile = io.open(config.filename, "a+");

		logfile:setvbuf("no");

		function send(payload)

			logfile:write(payload, "\n");

		end

	elseif config.udp_host and config.udp_port then

		local conn = socket.udp();

		conn:setpeername(config.udp_host, config.udp_port);

		function send(payload)

			conn:send(payload);

		end

	end

	local format = require "util.format".format;

	local do_format = config.formatted_as or false;

	return function (source, level, message, ...)

		local args = pack(...);

		for i = 1, args.n do

			if args[i] == nil then

				args[i] = json.null;

			elseif type(args[i]) ~= "string" or type(args[i]) ~= "number" then

				args[i] = tostring(args[i]);

			end

		end

		args.n = nil;

		local payload = {

			datetime = datetime(),

			source = source,

			level = level,

			message = message,

			args = array(args);

		};

		if do_format then

			payload[do_format] = format(message, ...)

		end

		send(json.encode(payload));

	end

end

function module.unload()

	-- deregister

	require"core.loggingmanager".register_sink_type("json", nil);

end

require"core.loggingmanager".register_sink_type("json", sink_maker);