rednet.open("bottom")
rednet.open("back")
speaker = peripheral.wrap("left")

function setState(con)
    redstone.setOutput("top", con)
    rednet.broadcast("n-word switched " .. con and "on" or "off" .. " at " .. textutils.formatTime(os.time()))
    local state = fs.open("last_state", "w")
    if con then
        speaker.playSound("minecraft:block.end_portal.spawn", 3)
        state.write("true")
    else
        state.write("false")
        speaker.playSound("minecraft:entity.wolf.whine", 3)
    end
end

laststate = fs.open("last_state", "w")
if laststate.readAll() == "true" then
    setState(true)
end

while true do
    id,message = rednet.receive("n")
    print("[" .. id .. "] " .. message)
    if id == 124 and message == "turn_on" then
        setState(true)
    elseif id == 124 and message == "turn_off" then
        setState(false)
    end
    sleep(0.1)
end