local depth = 50

local height = 2
local r = 3

function _detect(func)
  while turtle.detect() do
    if not func() then break end
  end
  while turtle.attack() do
  end
end

function dig()
  _detect(turtle.dig)
  turtle.turnRight()
  _detect(turtle.dig)
  turtle.turnLeft()
  turtle.turnLeft()
  _detect(turtle.dig)
  turtle.turnRight()
  _detect(turtle.digUp)
  _detect(turtle.digDown)
end

function fwd(n, flag_dig_all)
  local _fwd = function()
    repeat
      turtle.attack()
      turtle.dig()
      turtle.suck()
    until turtle.forward()
    return true
  end
  for i=1,n do
    if flag_dig_all then dig() end
    _fwd()
  end
end

function up(n)
  local _up = function()
    repeat
      turtle.digUp()
      turtle.attackUp()
      turtle.suckUp()
    until turtle.up()
    return true
  end

  for i=1,n do
    _up()
  end
end

function down(n)
  local _down = function()
  repeat
    turtle.attackDown()
    turtle.digDown()
    turtle.suckDown()
  until turtle.down()
  for i=1,n do
    _down()
  end
  return true
end

function backToHome()
  _detect(turtle.dig)
  repeat
    turtle.dig()
    turtle.attack()
  until turtle.forward()
  return true
end

-- main

fwd(depth, true)

turtle.turnRight()
turtle.turnRight()

down(3)

fwd(depth, true)

up(3)