-- ******************************* --
-- Autopilot Programme by Jharrakn --
-- ******************************* --

function stop(message)
	print("autopilot encountered an error and stopped")
	print("message recieved was:")
	print(message)
	print("")
	print("press r to restart")
	while true do
			local event, character = os.pullEvent()
			if event == "char" and character == "r" then break end
	end
	os.reboot()
end

local args = { ... }

if args[1] == nil or args[2] == nil then
	stop("program should be called with [x coord] [y coord]")
end


rednet.open("top")
local x, y, z = gps.locate(5, false)
if x == nil then stop("gps error") end

while x ~= tonumber(args[1]) do
	if x < tonumber(args[1]) then
		redstone.setBundledOutput("right", colors.white)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
		redstone.setBundledOutput("right", colors.white)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
	elseif x > tonumber(args[1]) then
		redstone.setBundledOutput("right", colors.magenta)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
		redstone.setBundledOutput("right", colors.magenta)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
	end

	x = nil
	x, y, z = gps.locate(5, false)
	if x == nil then stop("gps error") end
end

while y ~= tonumber(args[2]) do
	if y < tonumber(args[2]) then
		redstone.setBundledOutput("right", colors.lightBlue)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
		redstone.setBundledOutput("right", colors.lightBlue)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
	elseif y > tonumber(args[2]) then
		redstone.setBundledOutput("right", colors.orange)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
		redstone.setBundledOutput("right", colors.orange)
		sleep(0.5)
		redstone.setBundledOutput("right", 0)
		sleep(0.5)
	end

	x = nil
	x, y, z = gps.locate(5, false)
	if x == nil then stop("gps error") end
end

print("arrived at destination")