Clock4

function getDate()
	local result = http.get("http://worldtimeapi.org/api/timezone/America/New_York.txt") -- This is a synchronous request.  Seems easier.  Change to async if necessary
	-- Third line...
	lines = {}
	for s in result.readAll():gmatch("[^\r\n]+") do
		table.insert(lines, s)
	end
	local date = lines[2]
	-- Now we have: datetime: 2020-07-21T00:07:29.748572-04:00
	datepieces = {}
	for s in result.readAll():gmatch("[^\r\n]+") do
		table.insert(datepieces, s)
	end
	return datePieces[1]; -- Should just get the ISO date bit
end


-- This is super simple and had 0 upvotes, but, I don't need much.  I don't care about timezone or anything.

--    Parse date given in any of supported forms.

--    Note! For unrecognised format will return now.

--    @param str ISO date. Formats:
--        Y-m-d
--        Y-m -- this will assume January
--        Y -- this will assume 1st January



	-- We're looking for: datetime: 2020-07-20T23:50:33.619682-04:00

function parseDate(str)
    local y, m, d, hour, minute, second, ms = str:match("(%d%d%d%d)-?(%d?%d?)-?(%d?%d?)%a(%d%d):(%d%d):(%d%d).(%d%d%d)")
	-- Lua doesn't do ms... but we can make it work
    -- fallback to now
    if y == nil then
        return os.time()
    end
    -- defaults
    if m == '' then
        m = 1
    end
    if d == '' then
        d = 1
    end
    -- create time
    return os.time{year=y, month=m, day=d, hour=hour, min = minute, sec = second},ms -- Returning a datetime and a number for the ms
end



rednet.open("front")
targetid = 3 -- You still gotta set this if you move.

ticks = 0

ISODate = getDate()
t, ms = parseDate(ISODate)
starttime = t
startms = ms
endtime = starttime -- set this as we go
endms = ms
ratio = 1



while true do
	ticks = ticks + 1
	if ticks == 10 then -- Every 10 ticks, twice per second, is probably OK
		ISODate = getDate()
		t, ms = parseDate(ISODate)
		endtime = t
		endms = ms
			-- Easier said than done.
			-- I think we have to wait for an event
			-- But, our URL can maybe be http://worldtimeapi.org/api/timezone/America/New_York.txt

			-- Find the third line, datetime: 2020-07-20T23:50:33.619682-04:00
			-- Can lua parse that?


		second = os.difftime(endtime,starttime)
		second = second + (endms - startms)/1000
		tps = ticks/second
		-- Find ratio of this to the expected 20
		-- We want where 10 tps / 20expected = 0.5 speed (because of the way speed works, it's kinda backwards)
		ratio = tps/20
		print(ratio)
		-- Then send this new ratio out on rednet
		rednet.send(targetid,"speed " .. ratio)
		-- Reset
		ticks = 0
		starttime = endtime
	end
end