WoWInterface - WeakAura Nameplate custom Power-Text

I wrote a WeakAura to display Ressource/Powerbars to the default nameplates.

It is pretty easy to display text but I want my own text-format and I have issues to use my custom code for nameplates since I dont have a exact unit like player/target/focus.

My Weakaura as lua.import:
https://pastebin.com/q8SaDGMV

WeakAuras

Display
Custom/Common Text:

Code:

function()

    local power = UnitPower("UNIT");

    local maxPower = UnitPowerMax("UNIT");

    return string.format("%s", aura_env.pretty(power), aura_env.pretty(maxPower))

end

Action
Custom/Format Code:

Code:

aura_env.pretty = function(power)

    if power < 1000 then

        return string.format('%s', power)

    end

    if power < 1000000 then

        powerRed = power/1000

        suffix = 'k'

    elseif power < 1000000000 then

        powerRed = power/1000000

        suffix = 'm'

    else

        powerRed = power/1000000000

        suffix = 'b'

    end

    if powerRed < 10 then

        return string.format('%.1f%s', powerRed, suffix)

    elseif powerRed < 100 then

        return string.format('%.1f%s', powerRed, suffix)

    else

        return string.format('%.1f%s', powerRed, suffix)

    end

end

I could use the default/weakaura format options but I would prefer my own one.

If somebody has an idea/knows how to get this to work I would really appreciate some help :)