---------------------------------------------------
-- Licensed under the GNU General Public License v2
--  * (c) 2012, Axel Arnold <arnolda _at_ icp.uni-stuttgart.de>
--  * (c) 2010, Adrian C. <anrxc@sysphere.org>
--  * (c) 2010, Henning Glawe <glaweh@debian.org>
--  * (c) 2009, Lucas de Vries <lucas@glacicle.com>
---------------------------------------------------

---------------------------------------------------
-- looks for the given wireless devices (watch_devices),
-- and displays the up and downstream traffic.
---------------------------------------------------

local watch_devices = { "ppp0", "wlan0", "eth0" }

-- {{{ Grab environment
local pairs = pairs
local tonumber = tonumber
local os = { time = os.time }
local io = { open = io.open }
local setmetatable = setmetatable
local string = {
    match = string.match,
    format = string.format
}
-- }}}

-- Net: provides usage statistics for all network interfaces
module("mynet")

-- Initialise function tables
local nets = {}

-- {{{ Net widget type
local function worker(format)
   -- Get /proc/net/dev
   local f = io.open("/proc/net/dev")

   for device,val in pairs(nets) do
      nets[device].up   = nil
      nets[device].down = nil
   end

   for line in f:lines() do
      -- Match wmaster0 as well as rt0 (multiple leading spaces)
      if string.match(line, "^[%s]?[%s]?[%s]?[%s]?[%w]+:") then
	 local name = string.match(line, "^[%s]?[%s]?[%s]?[%s]?([%w]+):")
	 -- Received bytes, first value after the name
	 local recv = tonumber(string.match(line, ":[%s]*([%d]+)"))
	 -- Transmited bytes, 7 fields from end of the line
	 local send = tonumber(string.match(line,
					    "([%d]+)%s+%d+%s+%d+%s+%d+%s+%d+%s+%d+%s+%d+%s+%d$"))
	 local up   = 0
	 local down = 0

	 if nets[name] ~= nil then
	    local interval  = os.time() - nets[name].time >  0 and os.time() - nets[name].time or 1

	    down = (recv - nets[name].recv) / interval
	    up   = (send - nets[name].send) / interval
	 end

	 -- Store totals
	 nets[name] = { time = os.time(),
			recv = recv,
			send = send,
			up   = up,
			down = down }
      end
   end
   f:close()

   local args = { ["{device}"]="none",
		  ["{send}"]="0",
		  ["{recv}"]="0" }
   
   for idx,name in pairs(watch_devices) do
      if nets[name] ~= nil and nets[name].up ~= nil then
	 args["{send}"] = string.format("%.1f", nets[name].up/1024)
	 args["{recv}"] = string.format("%.1f", nets[name].down/1024)
	 args["{device}"] = name
         break
      end
   end
   
   return args
end
-- }}}

setmetatable(_M, { __call = function(_, ...) return worker(...) end })