Cube miner

--[[
Receives 3 arguments;
first argument is how many blocks in front the turtle will go,
second is how high it will go and
third is how many blocks to the right it will go.
]]

function move(direction)
  if direction == "up" then
    while turtle.up() == false do
      turtle.digUp()
      turtle.attackUp()
    end

  elseif direction == "forward" then
    while turtle.forward() == false do
      turtle.dig()
      turtle.attack()
    end

  elseif direction == "down" then
    while turtle.down() == false do
      turtle.digDown()
      turtle.attackDown()
    end
  end
end

cube = function(item)
  if item[1] ~= nil and item[2] ~= nil and item[3] ~= nil and tonumber(item[1]) and tonumber(item[2]) and tonumber(item[3]) and tonumber(item[1]) > 0 and tonumber(item[2]) > 0 and tonumber(item[3]) > 0 then
    for i=1,3 do
      item[i] = tonumber(item[i])
    end

    print("Mining out a " .. item[1] .. " x " .. item[2] .. " x " .. item[3] .. " cuboid")
    local xDist = item[1]
    local yDist = item[2]
    local zDist = item[3]
    local i = 0
    local levelsMined = 0

    function checkBreak()
      if yDist - levelsMined > 1 then
        turtle.digUp()
      end

      if yDist - levelsMined > 2 then
        turtle.digDown()
      end
    end

    function line()
      for k=1,xDist-1 do
        move("forward")
        checkBreak()
      end
    end

    function nextLine(direction)
      direction()
      move("forward")
      checkBreak()
      direction()
    end

    function layer(level)
      if yDist - levelsMined > 2 then
        move("up")
      end

      checkBreak()
      line()

      if zDist%2 == 1 then
        level = 0
      end

      for j=1,zDist-1 do
        if (level+j)%2 == 1 then
          nextLine(turtle.turnRight)

        else
          nextLine(turtle.turnLeft)
        end

        line()
      end

      if yDist - levelsMined > 2 then
        levelsMined = levelsMined + 3

      elseif yDist - levelsMined > 1 then
        levelsMined = levelsMined + 2

      else
        levelsMined = levelsMined + 1
      end
    end

    move("forward")
    layer(0)
    local level = 0

    while yDist - levelsMined > 0 do
      for l=1,2 do move("up") end
      for l=1,2 do turtle.turnRight() end

      level = level + 1
      layer(level)
    end

    local rightTurns = 2

    if level%2 == 0 then
      if zDist%2 == 1 then
        for i=1,2 do turtle.turnRight() end
        for i=1,xDist-1 do move("forward") end
      end

      turtle.turnRight()
      for i=1,zDist-1 do move("forward") end
      rightTurns = 1
    end

    local yOffset = 2
    if yDist % 3 == 1 then yOffset = 1 end

    for i=1,yDist-yOffset do move("down") end
    for i=1,rightTurns do turtle.turnRight() end

  else
    print("Invalid dimensions, use 3 numbers bigger than 0")
  end
end

cube({...})