local function checkFuel()
  if turtle.getFuelLevel() < 100 then
    select(16)
    if turtle.getItemCount() >= 100 then
      for i=0,100 do
        turtle.refuel()
      end
    else
      textutils.slowPrint("Please refuel")
    end
  end
end

local function checkStock()
  select(2)
  if turtle.getItemCount() == 0 then
    print("Not enough seeds")
  end
end

local function farm()
  select(5)
  turtle.digDown()
end

local function move()
  local success, data = turtle.inspectDown()
  if data.name != "minecraft:cobblestone_slab" then
    turtle.forward()
  else
    if dir==1 then
      turtle.turnLeft()
      turtle.forward()
      local success, data = turtle.inspectDown()
      if data.name != "minecraft:cobblestone_slab" then
        turtle.back()
        turtle.turnLeft()
      else
        turtle.turnLeft()
        turtle.forward()
        dir = 2
      end
    end
    if dir == 2 then
      turtle.turnRight()
      turtle.forward()
      local success, data = turtle.inspectDown()
      if data.name != "minecraft:cobblestone_slab" then
        turtle.back()
        turtle.turnRight()
      else
        turtle.turnRight()
        turtle.forward()
        dir = 1
      end
    end
  end

end

while true do
  checkFuel()
  checkStock()
  farm()
  move()
end