Light toolbar button when editable MIDI take is pooled (WIP).lua

function main()
  local newtime=os.time()
  -- slow down script frequency
  -- https://forum.cockos.com/showpost.php?p=1591089&postcount=14
  if newtime-lasttime >= 0.5 then -- run ~every 0.5 sec.
    lasttime = newtime
    local me = reaper.MIDIEditor_GetActive()
    if me ~= nil then
      -- iterate (enum) editable takes
      local i = 0
      local foundPooledTake = false
      while true do
        local take = reaper.MIDIEditor_EnumTakes(me, i, true)
        -- https://forum.cockos.com/showpost.php?p=2481441&postcount=11
        if take == nil or reaper.ValidatePtr(take, "MediaItem_Take*") == false then break end
        -- reaper.ShowConsoleMsg(tostring(take))
        local sourceType = reaper.GetMediaSourceType(reaper.GetMediaItemTake_Source(take), '')
        -- reaper.ShowConsoleMsg(sourceType)
        if sourceType == "MIDIPOOL" then 
          foundPooledTake = true
          break
        end
        i = i+1
      end -- while true do
      reaper.SetToggleCommandState(sectionID, cmdID, foundPooledTake and 1 or 0) -- convert boolean to 0/1
      -- reaper.ShowConsoleMsg(tostring(foundPooledTake and 1 or 0) .. "\n")
      reaper.RefreshToolbar2(sectionID, cmdID)
    end -- if me ~= nil then
  end -- if newtime - lasttime...

  reaper.defer(main) 
end -- main()