-- This function returns a formatted string with the current battery status. It
-- can be used to populate a text widget in the awesome window manager. Based
-- on the "Gigamo Battery Widget" found in the wiki at awesome.naquadah.org

local wibox = require("wibox")
local naughty = require("naughty")
local beautiful = require("beautiful")

local previous_percent = 0

function batteryInfo(adapter)
    local fcur = io.open("/sys/class/power_supply/"..adapter.."/energy_now")
    local fcap = io.open("/sys/class/power_supply/"..adapter.."/energy_full")
    local cur = fcur:read()
    local cap = fcap:read()
    fcur:close()
    fcap:close()

    local battery = math.floor(cur * 100 / cap)

    if battery > 100 then
        battery = 100
    end

    return battery
end

function isCharging(adapter)

    local fsta = io.open("/sys/class/power_supply/"..adapter.."/status")
    local sta = fsta:read()
    fsta:close()
    return not sta:match("Discharging")

end

function update_battery()

    local percent = batteryInfo('BAT0')
    local color
    local symbol

    if percent < 15 then
        color="red"
    elseif percent < 30 then
        color="orange"
    elseif percent > 90 then
        color="green"
    else
        color="white"
    end

    if isCharging('BAT0') then
        color = 'green'
        symbol = '⚡'
    else
        symbol = '%'
    end

    if previous_percent >= 15 and percent < 15 then
        naughty.notify({
            title = "Low battery...",
            text = "Battery level is lower than 15% !",
            fg="#000000",
            bg="#ff0000",
            timeout=5
        })
    end

    battery_widget:set_markup('<span color="' .. color .. '">' .. percent .. ' ' .. symbol .. '</span>')

    previous_percent = percent

end

battery_widget = wibox.widget.textbox()
battery_widget.timer = timer({timeout=5})
battery_widget.timer:connect_signal("timeout", update_battery)
battery_widget.timer:start()
update_battery()