monitor = peripheral.wrap("left")

chest1 = peripheral.wrap("chest_1")
chest2 = peripheral.wrap("chest_2")

letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

items = {}
sortedItems = {}
tableLength = 0

function addChest(chest)
  for i = 1, chest.getInventorySize(), 1 do
    item = chest.getStackInSlot(i)
    if item ~= null then
      if items[item["display_name"]] == null then
        itemEntry = {}
        itemEntry["name"] = item["display_name"]
        itemEntry["qty"] = item["qty"]
        items[item["display_name"]] = itemEntry
        tableLength = tableLength + 1
        sortedItems[tableLength] = itemEntry
      else
        items[item["display_name"]]["qty"] = items[item["display_name"]]["qty"] + item["qty"]
      end
    end
  end
end

function addChests()
  tableLength = 0
  items = {}
  sortedItems = {}
  addChest(chest1)
  addChest(chest2)
end

function sort()
  for i = tableLength - 1, 1, -1 do
    for j = 1, i, 1 do
      if string.find(letters, string.sub(sortedItems[j]["name"], 1, 1)) > string.find(letters, string.sub(sortedItems[j + 1]["name"], 1, 1)) then
        temp = sortedItems[j]
        sortedItems[j] = sortedItems[j+1]
        sortedItems[j+1] = temp
      end
    end
  end
end

function refreshMonitor()
  monitor.setTextScale(0.5)
  monitor.setCursorPos(1, 1)
  monitor.clear()
  for k, v in pairs(sortedItems) do
    monitor.write(v["name"] .. ": " .. v["qty"])
    x, y = monitor.getCursorPos()
    monitor.setCursorPos(1, y + 1)
  end
end

while true do
  addChests()
  sort()
  refreshMonitor()
  sleep(5)
end