-- Build Tools
-- dig v1

local args = { ... }

if args[1] == nil or args[2] == nil or args[3] == nil or turtle.getItemCount(1) < 1 or args[1] == "help" then
  print ("Usage: dig [forward length] [right length] [depth]")
  print ("Put an ender chest in the first slot")
  return
end

local tilt = 0
local flength = tonumber(args[1])
local rlength = tonumber(args[2])
local depth = tonumber(args[3])
local blocks = rlength * flength * depth

function step()
  while not turtle.forward() do
    turtle.dig()
  end
end

function stepUp()
  while not turtle.up() do
    turtle.digUp()
  end
end

function stepDown()
  while not turtle.down() do
    turtle.digDown()
  end
end

function placeUp()
  while not turtle.placeUp() do
    turtle.digUp()
  end
end

function rotateRight()
  turtle.turnRight()
  if vertical then
    stepUp()
  else
    step()
  end
  turtle.turnRight()
end

function rotateLeft()
  turtle.turnLeft()
  if vertical then
    stepUp()
  else
    step()
  end
  turtle.turnLeft()
end

-- Dump inventory into ender chest.
function dump()
  turtle.select(1)
  placeUp()
  for m = 16, 2, -1 do
    turtle.select(m)
    turtle.dropUp()
  end
  turtle.select(1)
  turtle.digUp()
end

-- Dig 'em up.
for i = 1, depth, 1 do
  for j = 1, rlength, 1 do
    for k = 1, flength, 1 do
      if turtle.getItemCount(16) > 0 then
        dump()
      end
      turtle.digDown()
      if k < flength then
        step()
      end
    end
    if j < rlength then
      if (j + tilt) % 2 == 0 then
        rotateRight()
      else
        rotateLeft()
      end
    end
  end
  if rlength % 2 == 0 and i % 2 ~= 0 then
    tilt = 1
  else
    tilt = 0
  end
  turtle.turnLeft()
  turtle.turnLeft()
  stepDown()
end

-- Raise to initial height.
for i = 1, depth, 1 do
  stepUp()
end

-- Return to origin.
if depth % 2 ~= 0 then
  if rlength % 2 == 0 then
    turtle.turnRight()
    for i = 1, rlength - 1, 1 do
      step()
    end
  else
    turtle.turnLeft()
    for i = 1, rlength - 1, 1 do
      step()
    end
    turtle.turnRight()
    for i = 1, flength - 1, 1 do
      step()
    end
  end
end