spindig

local cache = peripheral.wrap("top")
local saveFile = ".iter.dat"

if not cache then
  error("No cache.", 0)
end

local function save(file, n)
  local h, err = io.open(file, 'w')
  if h then
    h:write(n):close()
  else
    printError("Failed to open file for writing.")
    error(err, 0)
  end
end

local function load(file)
  local h, err = io.open(file, 'r')
  if h then
    local dat = h:read("*a")
    h:close()
    return tonumber(dat) + 1
  else
    if type(err) == "string" then
      if err:find("No such file") then
        printError("Save file missing, starting at 1.")
        os.sleep(2)
        return 1
      else
        printError("Failed to open file for reading.")
        error(err, 0)
      end
    else
      error("Unknown error occured while opening file for reading.")
    end
  end
end

local function iterateItems(func)
  local a = {}
  for i = 1, 16 do
    if turtle.getItemCount(i) > 0 then
      table.insert(a, func(i))
    end
  end
  return a
end

local function getCount()
  local tmp = cache.getItem(1)
  if tmp then
    return tmp.getMetadata().count
  else
    return 0
  end
end

local function getInvCount()
  return #iterateItems(function()
    return 1
  end)
end

local function doDump()
  local cnt = getCount()
  return cnt < 9000
end

local function dump()
  iterateItems(function(i)
    turtle.select(i)
    turtle.dropUp()
  end)
end

local function doDig()
  local inv = getInvCount()
  return inv >= 15 and not doDump() or true
end

local function dig()
  for i = 1, 4 do
    turtle.dig()
    turtle.turnRight()
  end
end

local c = load(saveFile)
while true do
  term.clear()
  term.setCursorPos(1, 1)
  print("Running iteration " .. tostring(c))

  local fl = true
  if doDig() then
    print("Digging.")
    dig()
    print("Done.")
  else
    print("Cannot dig.")
    fl = false
  end

  if doDump() then
    print("Dumping inv")
    dump()
    print("Done.")
  elseif not fl then
    error("Cannot dig and cannot dump.  Inventories are full.", 0)
  end

  print("Total items in cache: " .. tostring(getCount()))
  print("Saving.")
  save(saveFile, c)
  print("Done.")
  print("Waiting 60 seconds.")
  os.sleep(60)
  c = c + 1
end