-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

-- XEP-0082: XMPP Date and Time Profiles

local os_date = os.date;

local os_time = os.time;

local os_difftime = os.difftime;

local floor = math.floor;

local tonumber = tonumber;

local _ENV = nil;

-- luacheck: std none

local function date(t)

	return os_date("!%Y-%m-%d", t and floor(t) or nil);

end

local function datetime(t)

	if t == nil or t % 1 == 0 then

		return os_date("!%Y-%m-%dT%H:%M:%SZ", t);

	end

	local m = t % 1;

	local s = floor(t);

	return os_date("!%Y-%m-%dT%H:%M:%S.%%06dZ", s):format(floor(m * 1000000));

end

local function time(t)

	if t == nil or t % 1 == 0 then

		return os_date("!%H:%M:%S", t);

	end

	local m = t % 1;

	local s = floor(t);

	return os_date("!%H:%M:%S.%%06d", s):format(floor(m * 1000000));

end

local function legacy(t)

	return os_date("!%Y%m%dT%H:%M:%S", t and floor(t) or nil);

end

local function parse(s)

	if s then

		local year, month, day, hour, min, sec, tzd = s:match("^(%d%d%d%d)%-?(%d%d)%-?(%d%d)T(%d%d):(%d%d):(%d%d%.?%d*)([Z+%-]?.*)$");

		if year then

			local now = os_time();

			local time_offset = os_difftime(os_time(os_date("*t", now)), os_time(os_date("!*t", now))); -- to deal with local timezone

			local tzd_offset = 0;

			if tzd ~= "" and tzd ~= "Z" then

				local sign, h, m = tzd:match("([+%-])(%d%d):?(%d*)");

				if not sign then return; end

				if #m ~= 2 then m = "0"; end

				h, m = tonumber(h), tonumber(m);

				tzd_offset = h * 60 * 60 + m * 60;

				if sign == "-" then tzd_offset = -tzd_offset; end

			end

			local prec = sec%1;

			sec = floor(sec + time_offset) - tzd_offset;

			return os_time({year=year, month=month, day=day, hour=hour, min=min, sec=sec, isdst=false})+prec;

		end

	end

end

return {

	date     = date;

	datetime = datetime;

	time     = time;

	legacy   = legacy;

	parse    = parse;

};