awesome_configs/widgets/bat_linux.lua

-- battery widget type for GNU/Linux
-- Copyright (C) 2010  Adrian C. <anrxc@sysphere.org>
-- Copyright (C) 2013  NormalRa <normalrawr@gmail.com>
-- Copyright (C) 2017  David Udelson <dru5@cornell.edu>
-- Copyright (C) 2017  Roberto <empijei@users.noreply.github.com>
-- Copyright (C) 2017  mutlusun <mutlusun@github.com>
--
-- This file is part of Vicious.
--
-- Vicious is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as
-- published by the Free Software Foundation, either version 2 of the
-- License, or (at your option) any later version.
--
-- Vicious is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with Vicious.  If not, see <https://www.gnu.org/licenses/>.

-- {{{ Grab environment
local tonumber = tonumber
local string = { format = string.format }
local math = {
    min = math.min,
    floor = math.floor
}

local helpers = require"vicious.helpers"
-- }}}

-- {{{ Battery widget type
return helpers.setcall(function (format, warg)
    if not warg then return end

    local battery = helpers.pathtotable("/sys/class/power_supply/"..warg)
    local battery_state = {
        ["Full\n"]        = "↯",
        ["Unknown\n"]     = "⌁",
        ["Charged\n"]     = "↯",
        ["Charging\n"]    = "+",
        ["Discharging\n"] = "-"
    }

    -- Get current power usage in watt
    local curpower = "N/A"
    if battery.power_now then
        curpower = string.format("%.2f", tonumber(battery.power_now) /1000000)
    end

    -- Check if the battery is present
    if battery.present ~= "1\n" then
        return {battery_state["Unknown\n"], 0, "N/A", 0, curpower}
    end

    -- Get state information
    local state = battery_state[battery.status] or battery_state["Unknown\n"]

    -- Get capacity information
    local remaining, capacity, capacity_design
    if battery.charge_now then
        remaining, capacity = battery.charge_now, battery.charge_full
        capacity_design = battery.charge_full_design or capacity
    elseif battery.energy_now then
        remaining, capacity = battery.energy_now, battery.energy_full
        capacity_design = battery.energy_full_design or capacity
    else
        return {battery_state["Unknown\n"], 0, "N/A", 0, curpower}
    end

    -- Calculate capacity and wear percentage (but work around broken BAT/ACPI implementations)
    local percent = math.min(math.floor(remaining / capacity * 100), 100)
    local wear = math.floor(100 - capacity / capacity_design * 100)

    -- Get charge information
    local rate
    if battery.current_now then
        rate = tonumber(battery.current_now)
    elseif battery.power_now then
        rate = tonumber(battery.power_now)
    else
        return {state, percent, "N/A", wear, curpower}
    end

    -- Calculate remaining (charging or discharging) time
    local time = "N/A"

    if rate ~= nil and rate ~= 0 then
        local timeleft
        if state == "+" then
            timeleft = (tonumber(capacity)-tonumber(remaining)) / tonumber(rate)
        elseif state == "-" then
            timeleft = tonumber(remaining) / tonumber(rate)
        else
            return {state, percent, time, wear, curpower}
        end

        -- Calculate time
        local hoursleft   = math.floor(timeleft)
        local minutesleft = math.floor((timeleft - hoursleft) * 60 )

        time = string.format("%02d:%02d", hoursleft, minutesleft)
    end

    return {state, percent, time, wear, curpower}
end)
-- }}}