local socket = require "socket";

local time = require "util.time".now

local function new(config)

	if not config or not config.statsd_server then

		return nil, "No statsd server specified in the config, please see https://prosody.im/doc/statistics";

	end

	local sock = socket.udp();

	sock:setpeername(config.statsd_server, config.statsd_port or 8125);

	local prefix = (config.prefix or "prosody")..".";

	local function send_metric(s)

		return sock:send(prefix..s);

	end

	local function send_gauge(name, amount, relative)

		local s_amount = tostring(amount);

		if relative and amount > 0 then

			s_amount = "+"..s_amount;

		end

		return send_metric(name..":"..s_amount.."|g");

	end

	local function send_counter(name, amount)

		return send_metric(name..":"..tostring(amount).."|c");

	end

	local function send_duration(name, duration)

		return send_metric(name..":"..tostring(duration).."|ms");

	end

	local function send_histogram_sample(name, sample)

		return send_metric(name..":"..tostring(sample).."|h");

	end

	local methods;

	methods = {

		amount = function (name, initial)

			if initial then

				send_gauge(name, initial);

			end

			return function (new_v) send_gauge(name, new_v); end

		end;

		counter = function (name, initial) --luacheck: ignore 212/initial

			return function (delta)

				send_gauge(name, delta, true);

			end;

		end;

		rate = function (name)

			return function ()

				send_counter(name, 1);

			end;

		end;

		distribution = function (name, unit, type) --luacheck: ignore 212/unit 212/type

			return function (value)

				send_histogram_sample(name, value);

			end;

		end;

		sizes = function (name)

			name = name.."_size";

			return function (value)

				send_histogram_sample(name, value);

			end;

		end;

		times = function (name)

			return function ()

				local start_time = time();

				return function ()

					local end_time = time();

					local duration = end_time - start_time;

					send_duration(name, duration*1000);

				end

			end;

		end;

	};

	return methods;

end

return {

	new = new;

}