dig

local args = {...}
if #args < 2 then return end
os.loadAPI("utils")
local maxX, maxZ = 0 + args[1], 0 + args[2]
local count
local curX, curZ = turtle.x, turtle.z
local curY = turtle.y
for i = 1,16 do
  if turtle.getItemCount(i) == 0 then
    count = i - 1
    break
  end
end

local function suck()
  while turtle.suck() do end
  turtle.dig()
end

local function suckDown()
  while turtle.suckDown() do end
  turtle.digDown()
end

local function suckUp()
  while turtle.suckUp() do end
  turtle.digUp()
end

local function matches(func)
  if not count then return false end
  for i = 1, count do
    turtle.select(i)
    if func() then return true end
  end
  return false
end

local function tunnel(x)
  local func, func2, func3
  for j = 1, 2 do
    if j == 1 then
      func = turtle.compareUp
      func2 = suckUp
    else
      func = turtle.compareDown
      func2 = suckDown
    end
    for i = 1, x do
      turtle.select(count + 1)
      turtle.turnLeft()
      if not matches(turtle.compare) then
        suck()
      end
      turtle.turnRight()
      turtle.turnRight()
      if not matches(turtle.compare) then
        suck()
      end
      turtle.turnLeft()
      if not matches(func) then
        func2()
      end
      if i ~= x then
        suck()
        if not utils.forward() then return false end
      end
    end
    turtle.turnLeft()
    turtle.turnLeft()
    if j == 1 then
      turtle.digDown()
      turtle.down()
    else
      turtle.digUp()
      turtle.up()
    end
  end
  return true
end

while true do
  for z = curY % 4, maxZ - 1, 4 do
    while turtle.getFuelLevel() < 2 * (maxZ + maxZ - curY + 25) do
      os.sleep(1)
    end
    if not utils.goto(0, curY, z) then
      utils.goto(0, 0, 0)
      return
    end
    turtle.rotate(1, 0)
    if not tunnel(maxX) then return end
    utils.goto(0, 0, 0)
    turtle.rotate(-1, 0)
    for i = count + 1, 16 do
      turtle.select(i)
      turtle.drop()
    end
  end
  curY = curY - 2
end