startup

modem = peripheral.wrap("left")

function EditDestinations()
while true do
  local lsDestinations
  if fs.exists("destinations.ls") then
    --Load the existing destinations
    local file = fs.open("destinations.ls","r")
    local data = file.readAll()
    file.close()
    lsDestinations = textutils.unserialize(data)
  else
    lsDestinations = {}
  end

  --Display existing destinations
  print("\n")
  if #lsDestinations == 0 then
    print("No destinations exist\n")
  else
    for i=1,#lsDestinations do
      print(tostring(i)..". "..lsDestinations[i]["Display"])
    end
  end
  --Display option
  print("(a. Add)")
  --Receive input
  write("Your selection: ")
  local selection = read()

  --Decode selection
  if selection == "a" then
    write("\n\nEnter display name: ")
    local sName = read()
    write("Enter ticket: ")
    local sTicket = read()
    --Box this up
    local destination = {}
    destination["Display"] = sName
    destination["Ticket"] = sTicket
    --Add to the list
    table.insert(lsDestinations, destination)
  else
    local iSelection = tonumber(selection)
    if iSelection ~= null then
      if (iSelection <= #lsDestinations) then
        print("\n\nDisplay: " .. lsDestinations[iSelection]["Display"])
        print("Ticket: " .. lsDestinations[iSelection]["Ticket"])
        --Give options
        print("(d. Delete)")
        print("(e. Edit Display Name)")
        print("(t. Edit Ticket)")
        write("Your selection: ")
        selection = read()
        --Decode selection
        if selection == "d" then
          table.remove(lsDestinations,iSelection)
        elseif selection == "e" then
          write("New Display: ")
          local newName = read()
          lsDestinations[iSelection]["Display"] = newName
        elseif selection == "t" then
          write("New Ticket: ")
          local newTicket = read()
          lsDestinations[iSelection]["Ticket"] = newTicket
        else
          print("\nInvalid selection")
        end
      end
    else
      print("\nInvalid selection")
    end
  end

  --Save any edits to the list
  file = fs.open("destinations.ls","w")
  file.write(textutils.serialize(lsDestinations))
  file.close()
end
end

function ServeTickets()
while true do
  local event,side,freq,refreq,message = os.pullEvent("modem_message")
  if (message == "List") then
    --Load the list
    local data
    if fs.exists("destinations.ls") then
      local file = fs.open("destinations.ls","r")
      data = file.readAll()
      file.close()
    else
      local lsEmpty = {}
      data = textutils.serialize(lsEmpty)
    end
    --Send the list back on refreq
    modem.transmit(refreq,refreq,data)
  end
end
end

--Start the server
print("Starting server...")
modem.open(10)
print("Server listening on frequency 10.\n\n")
--Run EditDestinations and ServeTickets in parallel
parallel.waitForAll(EditDestinations,ServeTickets)