oUF Simple 

function()
    local this = WeakAuras.regions[aura_env.id].region
    local thisSpell = GetSpellInfo(203720)
    local c,_,s,d = GetSpellCharges(thisSpell)
    
    if c and c > 0 then
        this:SetInverse(false)
        return 1,1,true 
    elseif c == 0 and d then
        this:SetInverse(true)
        return d, s + d        
    else
        this:SetInverse(false)
        return 0,1,true
    end
end

function()
    local c,_,s,d = GetSpellCharges(203720)
    
    if (c == nil) or (c >= 1) then
        return ""
    elseif (c == 0) and (d) and (s) then
        return string.format("%.1f",s + d - GetTime())
    else
        return "Unknown"
    end
end