local wakeup = {
	port = 9,
}


--- Reads configuration file at [[path]] and parses a pair of MAC and broadcast addresses from it. Builds a Wake-on-LAN
--- magic packet and saves it for later use with :worker(). Returns true if no errors were encountered, otherwise a nil.
function wakeup:configure (path)
	local fd = file.open(path)
	if not fd then
		print("Config file not found", path)
		return
	end
	local line = fd:readline()
	fd:close()
	fd = nil
	self.mac, self.addr = line:match("^(%S+)%s+(%S+)")
	self.data = ""
	for octet in self.mac:gmatch("%x%x") do
		self.data = self.data .. string.char(tonumber(octet, 16))
	end
	if #self.data ~= 6 then
		print(string.format("Invalid MAC\t%q", self.mac))
		return
	end
	self.data = string.char(0xff):rep(6) .. self.data:rep(16)
	return true
end


function wakeup:open ()
	self.udp = net.createUDPSocket()
end


function wakeup:close ()
	if self.udp then
		self.udp:close()
	end
end


--- Creates a new counter that has :up() method that returns true until it gets called N [[times]]. Then it returns only
--- false.
local
function new_counter (times)
	return {
		count = 0,
		times = times,
		up = function (self)
			self.count = self.count + 1
			return self.count <= self.times
		end,
	}
end


--- Begins to send Wake-on-LAN magic packets to the broadcast [[.addr]] for selected [[.mac]]. Packets are sent several
--- [[times]] each separated by [[interval]]. Callback is called [[after]] all packets are sent.
function wakeup:sendout (interval, times, after)
	self:open()
	local count = new_counter(times)
	return tmr.create():alarm(interval, tmr.ALARM_SEMI, function (timer)
		if count:up() then
			print("Waking up", self.mac, self.addr)
			self.udp:send(self.port, self.addr, self.data)
			timer:start()
		else
			timer:unregister()
			self:close()
			after()
		end
	end)
end


--- Sets up Wake Up to run when wifi is connected and configured in a network. Runs callbacks [[before]] send-outs, and
--- [[after]] they are done.
function wakeup:setup (before, after)
	if not self:configure("wakeup.conf") then
		error("Could not configure wakeup")
	end
	wifi.eventmon.register(wifi.eventmon.STA_GOT_IP, function ()
		before()
		self:sendout(500, 5, after)
	end)
end


return function ()
	gpio.write(4, gpio.HIGH)
	gpio.mode(4, gpio.OUTPUT)

	tmr.create():alarm(1000, tmr.ALARM_SINGLE, function ()
		wakeup:setup(
			function () gpio.write(4, gpio.LOW) end,
			function ()
				wifi.setmode(wifi.NULLMODE, false)
				gpio.write(4, gpio.HIGH)
			end
		)
		wifi.setmode(wifi.STATION, false)
		wifi.sta.connect()
	end)
end