-- wrap your peripherals
local ctrl   = peripheral.wrap("left")
local stress = peripheral.wrap("top")

-- parameters
local maxSpeed  = 256     -- absolute RPM limit
local minSpeed  = 1       -- keep it turning
local loopDelay = 0.5     -- seconds between adjustments

-- initialize targetSpeed
local targetSpeed = math.max(minSpeed, math.min(maxSpeed, ctrl.getTargetSpeed() or minSpeed))
ctrl.setTargetSpeed(targetSpeed)

-- control loop
while true do
  -- read current values
  local currentStress = stress.getStress()
  local cap           = stress.getStressCapacity()
  -- get what the controller currently has set
  local currentSpeed  = ctrl.getTargetSpeed() or targetSpeed

  -- compute stress per RPM directly
  local stressPerRPM = currentStress / currentSpeed

  -- compute the RPM that would put us right at capacity
  local idealSpeed = math.floor(cap / stressPerRPM)

  -- clamp to min/max
  idealSpeed = math.max(minSpeed, math.min(maxSpeed, idealSpeed))

  -- only update if it actually changes
  if idealSpeed ~= currentSpeed then
    targetSpeed = idealSpeed
    ctrl.setTargetSpeed(targetSpeed)

        -- print status
    print(string.format(
      "Stress: %d/%d (%.1f%%) | %.4f stress/RPM | Speed: %d RPM",
      currentStress, cap, (currentStress/cap)*100, stressPerRPM, targetSpeed
    ))
  end

  os.sleep(loopDelay)
end