Sorting Turtle

local sortSlots = {}
local input = turtle.suckDown
local output = turtle.dropUp
local wait = 10

local facing = 0
function orient(dir)
  if facing == dir then
    return
  elseif math.abs(facing - dir) == 2 then
    turtle.turnLeft()
    turtle.turnLeft()
    facing = dir
  elseif facing - dir == 1 or facing - dir == -3 then
    turtle.turnLeft()
    facing = dir
  else
    turtle.turnRight()
    facing = dir
  end
end

for i = 1, 16 do
  if turtle.getItemCount(i) > 0 then
    sortSlots[i] = true
  end
end
while true do
  -- get items
  turtle.select(1)
  while input() do
  end
  local full = {}
  for slot = 1, 16 do
    if sortSlots[slot] and turtle.getItemCount(slot) > 1
        or not sortSlots[slot] and turtle.getItemCount(slot) > 0 then
      turtle.select(slot)
      local similarSlots = {}
      for sortSlot in pairs(sortSlots) do
        if turtle.compareTo(sortSlot) then
          table.insert(similarSlots, sortSlot)
        end
      end
      if #similarSlots > 0 then
        for i, sortSlot in ipairs(similarSlots) do
          local chest = math.floor((sortSlot-1)/4)
          if not full[chest] then
            orient(chest)
            local amount = turtle.getItemCount(slot)
            if sortSlots[slot] then
              amount = amount - 1
            end

            -- temp fix for duplication bug
            while amount > 64 do
              if not turtle.drop(64) then
                full[chest] = true
                break
              end
              amount = amount - 64
            end
            if not full[chest] then
            -- end temp fix

              if turtle.drop(amount) then
                break
              else
                full[chest] = true
              end

            -- temp fix
            end
            -- end temp fix

          end
        end
      else
        output()
      end
    end
  end
  orient(0)
  sleep(wait)
end