simplisticDig

local skip = ...
local sDistance = 2
if type(tonumber(skip)) == "number" then
  sDistance = tonumber(skip)
end
local dist = 0
local maxDist = 0
local dug = 0

local function checkInv()
  local o = 0
  for i = 1, 16 do
    if turtle.getItemCount(i) > 0 then
      o = o + 1
    end
  end
  if o >= 15 then return true end
  return false
end

local function dropEverything()
  for i = 1, 16 do
    turtle.select(i)
    turtle.drop()
  end
end

local function revert()
  turtle.up = turtle.native.up
  turtle.down = turtle.native.down
  turtle.dig = turtle.native.dig
  turtle.digDown = turtle.native.digDown
end

local function changeTurtleStuff()
  function turtle.down()
    local ok, err = turtle.native.down()
    if ok then
      dist = dist + 1
      if dist > maxDist then
        maxDist = dist
      end
    end
    return ok, err
  end

  function turtle.up()
    local ok, err = turtle.native.up()
    if ok then
      dist = dist - 1
    end
    return ok, err
  end

  function turtle.dig()
    local ok, err = turtle.native.dig()
    if ok then
      dug = dug + 1
    end
    return ok, err
  end

  function turtle.digDown()
    local ok, err = turtle.native.digDown()
    if ok then
      dug = dug + 1
    end
    return ok, err
  end
end


local function checkFuel()
  local fuel = turtle.getFuelLevel()

  print("We normally need to dig about 50-100 blocks down.")
  print("That means we normally need about 100-200 fuel.")
  print("We have " .. tostring(fuel) .. " / 200 fuel.")

  if fuel >= 100 and fuel <= 200 then
    print("We may be able to make it, but we may not.")
    print("Wait 10 seconds to start, or terminate now to stop.")
    os.sleep(10)
  end
  if fuel < 100 then
    error("We do not have enough fuel.")
  end
end

local function returnToSurface(t)
  print("Made it to " .. tostring(maxDist) .. ", returning.")
  while dist > 0 do
    turtle.up()
  end
  if t then
    local cFlag = false
    for i = 1, 4 do
      local a = peripheral.getType("front")
      if a then
        if a:find("chest") then
          cFlag = true
          break
        end
      end
      turtle.turnRight()
    end
    if cFlag then
      dropEverything()
    else
      error("No chest, inventory too full.")
    end

    checkFuel()
  end
end

local function go(distt)
  -- move down two blocks to be just under the top block
  checkFuel()
  local function hopDown(dy)
    for i = 1, dy do
      turtle.digDown()
      turtle.down()
    end
  end

  hopDown(distt)

  -- dig circle then go down
  local fails = 0
  repeat
    if fails == 0 then
      for i = 1, 3 do
        turtle.dig()
        turtle.turnRight()
      end
      turtle.dig()
      turtle.digDown()
      if checkInv() then
        returnToSurface(true)
        checkFuel()
        hopDown(maxDist - 1)
      end
    end
    local f = turtle.down()
    if not f then
      turtle.attackDown()
      turtle.digDown()
      fails = fails + 1
    else
      fails = 0
    end
  until fails > 10

  returnToSurface()

  print("Job complete")
  print("Went " .. tostring(maxDist) .. " blocks down.")
  print("That means " .. tostring(maxDist * 2) .. " fuel was used.")
  print("Dug " .. tostring(dug) .. " blocks total.")
end

changeTurtleStuff()
if skip == "unknown" then
  sDistance = 0
  while turtle.down() do end
end
go(sDistance)
revert()