light

-- Initialize variables
local running = false
local pulseDuration = 0.5
local timeBetweenOutputs = 0.5
local pulseCount = 3
local channel = 11
local modem = peripheral.find("modem")
local stateFile = "state.txt"

modem.open(channel)

local function resetAllOutputs()
  redstone.setOutput("left", false)
  redstone.setOutput("back", false)
  redstone.setOutput("right", false)
  redstone.setOutput("top", false)
end

local function saveState(side)
  local file = fs.open(stateFile, "w")
  file.write(side)
  file.close()
end

local function readState()
  if fs.exists(stateFile) then
    local file = fs.open(stateFile, "r")
    local state = file.readAll()
    file.close()
    return state
  end
  return nil
end

local function sendPulse(side)
  saveState(side)
  for i = 1, pulseCount do
    redstone.setOutput(side, true)
    sleep(pulseDuration)
    redstone.setOutput(side, false)
    sleep(pulseDuration)
  end
end

local function runSequence()
  local startingState = readState()
  local sides = {"left", "back", "right", "top"}
  local start = 1

  for i, side in ipairs(sides) do
    if side == startingState then
      start = i
      break
    end
  end

  resetAllOutputs()

  while running do
    for i = start, #sides do
      sendPulse(sides[i])
      sleep(timeBetweenOutputs)
    end
    start = 1  -- Reset to the beginning for the next loop
  end

  resetAllOutputs()
  fs.delete(stateFile)  -- Clear saved state
end

-- Main loop
while true do
resetAllOutputs()
  print("Listening for 'start' or 'stop' on channel " .. channel .. ".")
  local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")

  if message == "start" then
    running = true
    print("Starting sequence.")
    parallel.waitForAny(runSequence, function()
      local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
      if message == "stop" then
        running = false
        print("Stopping sequence.")
      end
    end)
  elseif message == "stop" then
    running = false
    print("Stopping sequence.")
  end
end