local args = { ... }
if #args ~= 2 then
  print( "Usage: digplus <number of columns> <depth>" )
  error()
end

maxCols = args[1]
depth = args[2]


function tryDig()
  if turtle.detect() then
    result = turtle.dig()
    if result then
      return true
    end
  end
  return false
end

function tryDigDown()
  if turtle.detectDown() then
    result = turtle.digDown()
    if result then
      return true
    end
  end
  return false
end

function tryDigUp()
  if turtle.detectUp() then
    result = turtle.digUp()
    if result then
      return true
    end
  end
  return false
end

function tryDigLeft()
  turtle.turnLeft()
  if turtle.detect() then
    result = turtle.dig()
    if result then
      turtle.turnRight()
      return true
    end
  end
  turtle.turnRight()
  return false
end

function tryDigRight()
  turtle.turnRight()
  if turtle.detect() then
    result = turtle.dig()
    if result then
      turtle.turnLeft()
      return true
    end
  end
  turtle.turnLeft()
  return false
end

var down = 1
for var col = 0, maxCols do
  for var z = 0, depth do
    turtle.select(1)
    if turtle.getFuelLevel() < 20 then
      turtle.refuel(1)
    end
    if down == 1 then
      tryDigDown()
      turtle.down()
    else
      tryDigUp()
      turtle.down()
    end
    tryDigLeft()
    tryDigRight()
    tryDig()
  end
  if down == 1 then
    down = 0
  else
    down = 1
  end
  turtle.forward()
  tryDig()
  turtle.forward()
end
~