battery.lua

-- Source: http://awesome.naquadah.org/wiki/Closured_Battery_Widget
local io = io
local math = math
local naughty = naughty
local beautiful = beautiful
local tonumber = tonumber
local tostring = tostring
local print = print
local pairs = pairs

module("battery")

local limits = {{25, 5},
	  {12, 3},
	  { 7, 1},
	    {0}}

function get_bat_state (adapter)
    local fcur = io.open("/sys/class/power_supply/"..adapter.."/charge_now")
    local fcap = io.open("/sys/class/power_supply/"..adapter.."/charge_full")
    local fsta = io.open("/sys/class/power_supply/"..adapter.."/status")
    local cur = fcur:read()
    local cap = fcap:read()
    local sta = fsta:read()
    fcur:close()
    fcap:close()
    fsta:close()
    local battery = math.floor(cur * 100 / cap)
    if sta:match("Charging") then
	dir = 1
    elseif sta:match("Discharging") then
	dir = -1
    else
	dir = 0
	battery = ""
    end
    return battery, dir
end

function getnextlim (num)
    for ind, pair in pairs(limits) do
	lim = pair[1]; step = pair[2]; nextlim = limits[ind+1][1] or 0
	if num > nextlim then
	    repeat
		lim = lim - step
	    until num > lim
	    if lim < nextlim then
		lim = nextlim
	    end
	    return lim
	end
    end
end


function batclosure (adapter)
    local nextlim = limits[1][1]
    return function ()
	local prefix = "⚡"
	local battery, dir = get_bat_state(adapter)
	if dir == -1 then
	    dirsign = "↓"
	    prefix = "Bat:"
	    if battery <= nextlim then
		naughty.notify({title = "⚡ Beware! ⚡",
			    text = "Battery charge is low ( ⚡ "..battery.."%)!",
			    timeout = 7,
			    position = "bottom_right",
			    fg = beautiful.fg_focus,
			    bg = beautiful.bg_focus
			    })
		nextlim = getnextlim(battery)
	    end
	elseif dir == 1 then
	    dirsign = "↑"
	    nextlim = limits[1][1]
	else
	    dirsign = ""
	end
	if dir ~= 0 then battery = battery.."%" end
	return " "..prefix.." "..dirsign..battery..dirsign.." "
    end
end