Todo List

os.loadAPI("write")
local mon = peripheral.wrap("right")
rednet.open("back")

local function createList()
  todo = {}
  local h = fs.open("todoList", "r")
  while true do
    nextLine = h.readLine()
    if nextLine ~= nil then
      table.insert(todo, nextLine)
    else
      break
    end
  end
  h.close()
end

local acceptanceID = 47

while true do
  createList()
  mon.setBackgroundColor(colors.black)
  mon.setTextColor(colors.white)
  mon.clear()
  mon.setCursorPos(1,1)
  mon.write("Todo: ")
  mon.setCursorPos(1,3)
  for i = 1,#todo do
    --mon.write(i..". "..todo[i])
    write.center(i..", "..todo[i])
    --mon.setCursorPos(1,3+i)
  end

  id, msg = rednet.receive()
  if id == acceptanceID then
    if string.find(msg, "ADD") ~= nil then
      spot = string.find(msg, " ")+1
      newTodo = string.sub(msg, spot)
      h = fs.open("todoList","a")
      h.write(newTodo.."\n")
      h.close()
    elseif string.find(msg, "DEL") ~= nil then
      spot = string.find(msg, " ")+1
      delNum = string.sub(msg,spot)
      if tonumber(delNum) ~= nil then
        table.remove(todo,tonumber(delNum))
        h = fs.open("todoList","w")
        for i = 1,#todo do
          h.write(todo[i].."\n")
        end
        h.close()
      end
    end
  end
end