Refuel Turtle from Chest

function refuelFromChest()
  -- version 1.02
  -- using pull items to test direction

  -- version 1.01
  -- fixed empty chest causing stack size -1

  -- turtle must be be looking at chest
  local directions = {"north", "south", "east", "west"}
  local chestDirection = ""

  -- these item IDs can be taken as fuel
  local fuel = {327, 4600, 7796, 263}

  -- connect to the chest
  local chest = peripheral.wrap("front")
  if not chest then
    print("Failed to connect to chest at front side.")
    return false
  end

  -- get all stacks from chest
  local chestStacks = chest.getAllStacks()
  if not chestStacks then
    print("Could not scan chest.")
    return false
  end

  -- check if there is a free slot. If not try to condense
  if #chestStacks == chest.getInventorySize() then
     chest.condenseItems();
    -- space available now?
    if #chestStacks == chest.getInventorySize() then
       print("Chest is full. Please clean at least one slot. Preferebaly Slot 1.")
       return false
    end
  end

  -- check if slot 1 is free. If not, try to swap with the next available
  local swappedStack = 0
  if chestStacks[1] then
    for i = 2, chest.getInventorySize() do
      if not chestStacks[i] then
        chest.swapStacks(1, i)
        chestStacks = chest.getAllStacks()
        swappedStack = i
        break
      end
    end
  end

  -- take slot 1 from turtle into chest
  turtle.select(1)

  -- probe test direction
  for i = 1, #directions do
    chestDirection = directions[i]
    if chest.pullItem(chestDirection, 1) > 0 then
      break
    end
  end

  -- take fuel from chest
  local refueled = false
  for k,v in pairs(chestStacks) do
    local item = chestStacks[k].id
    for i = 1, #fuel do
      if item == fuel[i] then
        chest.pushItem(chestDirection, k)
        if turtle.refuel() then
          refuel = true
        end
        turtle.select(1)
        chest.pullItem(chestDirection, 1)
      end
    end
  end

  -- give turtle back its first slot stack
  turtle.select(1)
  chest.pushItem(chestDirection, 1)

  -- when swapped then but item back to slot 1
  if swappedStack > 1 then
    chest.swapStacks(swappedStack, 1)
  end

  return refueled
end

refuelFromChest()