-- Copy file here ==> /lib/gluon/announce/nodeinfo.d/wifistats

SAVE_FILE = "/tmp/wifiutilization.txt"
INTERFACE = "mesh0"

function execute_command(command)
  cmd = assert (io.popen (command))
  local output = ""
  for line in cmd:lines() do
     output = output..'\n'..line
  end -- for loop
  cmd:close()
  return output
end


function get_last_data()
  local filehandle,err = io.open(SAVE_FILE,"r")
  if err then return false; end

  local line = filehandle:read('*l')
  if line then
    local _, _, active_time, busy_time = string.find(line,"^([0-9]*) ([0-9]*)$")
    if active_time and busy_time then
      filehandle:close()
      return {active_time=tonumber(active_time), busy_time=tonumber(busy_time)}
    else
      filehandle:close()
      return false
    end
  else
    filehandle:close()
    return false
  end
end


function get_current_data()
  local output = execute_command("iw dev "..INTERFACE.." survey dump")
  local data = {}
  local _, _, active_time, busy_time = string.find(output,'%[.-%]\n.-\n.-([0-9]-) ms\n.-([0-9]-) ms')
  if active_time and busy_time then
    return {active_time=tonumber(active_time), busy_time=tonumber(busy_time)}
  else
    return false
  end
  -- retry / transmitted_frame_count * 100
  local output = execute_command("cat /sys/kernel/debug/ieee80211/phy0/statistics/transmitted_frame_count")
  local  _, _, tx_frame_count = string.find(output,'^([0-9]-)$')

  local output = execute_command("cat /sys/kernel/debug/ieee80211/phy0/statistics/retry_count")
  local  _, _, retry_count = string.find(output,'^([0-9]-)$')

  local output = execute_command("cat /sys/kernel/debug/ieee80211/phy0/statistics/multiple_retry_count")
  local  _, _, multiple_retry_count = string.find(output,'^([0-9]-)$')

  local output = execute_command("cat /sys/kernel/debug/ieee80211/phy0/statistics/failed_count")
  local  _, _, failed_count = string.find(output,'^([0-9]-)$')

local output = execute_command("cat /sys/kernel/debug/ieee80211/phy0/statistics/frame_duplicate_count")
  local  _, _, frame_duplicate_count = string.find(output,'^([0-9]-)$')

end


function set_data(data)
  local filehandle,err = io.open(SAVE_FILE,"w+")
  if err then return false; end

  filehandle:write(data["active_time"].." "..data["busy_time"].."\n")
  filehandle:flush()
  filehandle:close()
  return true
end



current_data = get_current_data()

if current_data then
  last_data = get_last_data()
  if last_data then
    local last_minute = {active=(current_data["active_time"] - last_data["active_time"]), busy=(current_data["busy_time"] - last_data["busy_time"])}
    last_minute["utilization"] = string.format("%.2f", last_minute["busy"] / last_minute["active"])
    set_data(current_data)
    return{total={active=current_data["active_time"], busy=current_data["busy_time"], utilization=string.format("%.2f", current_data["busy_time"] / current_data["active_time"])}, last_minute=last_minute}
  end
  set_data(current_data)
end




--Sample data
--Survey data from mesh0
--      frequency:                      2412 MHz [in use]
--      noise:                          -95 dBm
--      channel active time:            785305812 ms
--      channel busy time:              197674023 ms
--      channel receive time:           175420195 ms
--      channel transmit time:          16634930 ms