TwilightPortal

local function isempty(s)
    return (s == nil or s == "")
end

local function help()
    print("Use:")
    print("TwilightPortal [command] (time)")
    print("")
    print("command - Can be either \"open\" or \"close\" to open or close the portal")
    print("")
    print("time - Optional. This is the amount of time (in seconds) that you want the command to run for")
    print("")
end

args = {...}

command = args[1]
time = tonumber(args[2])

if command == "help" then
    help()
end


if command == "close" then
    redstone.setOutput("back", true)

    if not isempty(time) then
        print(string.format("Twilight Portal is closed for %02d seconds", time))
        sleep(time)
        redstone.setOutput("back", false)
    end

else

    if command == "open" then
        redstone.setOutput("back", false)

        if not isempty(time) then
            print(string.format("Twilight Portal is open for %02d seconds", time))
            sleep(time)
            redstone.setOutput("back", true)
        end

    end

end

if command ~= "open" and command ~= "close" and command ~= "help" then
    print("ERROR: The first arg has to be either \"open\" or \"close\" ")
    print("")
    print("For help, do \"TwilightPortal help\" ")
end