--note to self: metadata - block, damage - item
function compareBlocks(data1, data2)
  return (data1.name == data2.name and data1.metadata == data2.metadata)
end

function damageToMetadata(data)
  return {name = data.name, metadata = data.damage}
end

function selectItem(name)
  for i = 1, 16 do
    turtle.select(i)
    if turtle.getItemCount() > 0 then
      if turtle.getItemDetail().name == name then
        return true
      end
    end
  end
  return false
end

function breakAllAbove()
  while turtle.detectUp() do
    turtle.digUp()
    turtle.up()
  end
  while not turtle.detectDown() do
    turtle.down()
  end
end

function compareDown(compareData)
  local success, data = turtle.inspectDown()
  return (data.name == compareData.name and data.metadata == compareData.metadata)
end

local arg = {...}

turtle.select(1)
local block = damageToMetadata(turtle.getItemDetail())
local size = tonumber(arg[1])
turtle.dig()
turtle.forward()
for y = 1, size do
  for x = 1, size do
    if not compareDown(block) then
      turtle.digDown()
      selectItem(block.name)
      turtle.placeDown()
    end
    breakAllAbove()
    if x < size then
      turtle.dig()
      turtle.forward()
    end
  end
  if y < size then
    local direction = (y % 2 == 0)
    if direction then
      turtle.turnLeft()
    else
      turtle.turnRight()
    end
    turtle.dig()
    turtle.forward()
    if direction then
      turtle.turnLeft()
    else
      turtle.turnRight()
    end
  end
end