-------------------------------------------------
-- Net Speed Widget for Awesome Window Manager
-- Shows current upload/download speed
-- More details could be found here:
-- https://github.com/streetturtle/awesome-wm-widgets/tree/master/net-speed-widget

-- @author Pavel Makhov
-- @copyright 2020 Pavel Makhov
-------------------------------------------------

local watch = require("awful.widget.watch")
local wibox = require("wibox")

local HOME_DIR = os.getenv("HOME")
local WIDGET_DIR = HOME_DIR .. '/.config/awesome/awesome-wm-widgets/net-speed-widget/'
local ICONS_DIR = WIDGET_DIR .. 'icons/'

local net_speed_widget = wibox.widget {
    {
        id = 'rx_speed',
        forced_width = 55,
        align = 'right',
        widget = wibox.widget.textbox
    },
    {
        image = ICONS_DIR .. 'down.svg',
        widget = wibox.widget.imagebox
    },
    {
        image =  ICONS_DIR .. 'up.svg',
        widget = wibox.widget.imagebox
    },
    {
        id = 'tx_speed',
        forced_width = 55,
        align = 'left',
        widget = wibox.widget.textbox
    },
    layout = wibox.layout.fixed.horizontal,
    set_rx_text = function(self, new_rx_speed)
        self:get_children_by_id('rx_speed')[1]:set_text(tostring(new_rx_speed))
    end,
    set_tx_text = function(self, new_tx_speed)
        self:get_children_by_id('tx_speed')[1]:set_text(tostring(new_tx_speed))
    end
}

local prev_rx = 0
local prev_tx = 0

local function convert_to_h(bytes)
    local speed
    local dim
    local bits = bytes * 8
    if bits < 1000 then
        speed = bits
        dim = 'b/s'
    elseif bits < 1000000 then
        speed = bits/1000
        dim = 'kb/s'
    elseif bits < 1000000000 then
        speed = bits/1000000
        dim = 'mb/s'
    elseif bits < 1000000000000 then
        speed = bits/1000000000
        dim = 'gb/s'
    else
        speed = tonumber(bits)
        dim = 'b/s'
    end
    return math.floor(speed + 0.5) .. dim
end

local function split(string_to_split, separator)
    if separator == nil then separator = "%s" end
    local t = {}

    for str in string.gmatch(string_to_split, "([^".. separator .."]+)") do
        table.insert(t, str)
    end

    return t
end

local function worker(user_args)

    local args = user_args or {}

    local interface = args.interface or '*'
    local timeout = args.timeout or 1

    local update_widget = function(widget, stdout)

        local cur_vals = split(stdout, '\r\n')

        local cur_rx = 0
        local cur_tx = 0

        for i, _ in ipairs(cur_vals) do
            if i%2 == 1 then cur_rx = cur_rx + cur_vals[i] end
            if i%2 == 0 then cur_tx = cur_tx + cur_vals[i] end
        end

        local speed_rx = cur_rx - prev_rx
        local speed_tx = cur_tx - prev_tx

        widget:set_rx_text(convert_to_h(speed_rx))
        widget:set_tx_text(convert_to_h(speed_tx))

        prev_rx = cur_rx
        prev_tx = cur_tx
    end

    watch(string.format([[bash -c "cat /sys/class/net/%s/statistics/*_bytes"]], interface),
        timeout, update_widget, net_speed_widget)

    return net_speed_widget

end

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