s&box Hints GameObjectSystem: UI hint queue

public class Hints : GameObjectSystem<Hints>
{
    [ConVar("cl_showhints", ConVarFlags.Saved | ConVarFlags.GameSetting)]
    public static bool cl_showhints { get; set; } = true;

    public void Queue(string hintName, string hintIcon, float delay);
    public void Cancel(string hintName);
}

// Queue a hint to display after 5 seconds
Hints.Current.Queue("my_hint", "ℹ️", 5.0f);

// Cancel a queued hint
Hints.Current.Cancel("my_hint");

public class Hints : GameObjectSystem<Hints>
{
    record class Hint(string Name, string Icon, RealTimeUntil Delay)
    {
        public bool Ready => Delay < 0;
    }

    List<Hint> _queue = new();

    public Hints(Scene scene) : base(scene)
    {
        // Queue default hints
        Queue("openspawnmenu", "ℹ️", 10);
        Queue("openinspectmenu", "ℹ️", 40);
        Queue("openpausemenu", "ℹ️", 70);

        Listen(Stage.StartUpdate, 0, Tick, "UpdateHints");
    }

    public void Queue(string hintName, string hintIcon, float delay)
    {
        _queue.Add(new Hint(hintName, hintIcon, delay));
    }

    void Tick()
    {
        if (timeSinceLast < 3) return;
        if (!cl_showhints) return;

        var next = _queue.Where(x => x.Ready).FirstOrDefault();
        if (next is null) return;

        _queue.Remove(next);
        timeSinceLast = 0;

        var phrase = Game.Language.GetPhrase($"hint.{next.Name}");
        phrase = ReplaceSpecialTokens(phrase);

        Notices.AddNotice(next.Icon, Color.White, phrase, 5);
    }

    public void Cancel(string hintName)
    {
        _queue.RemoveAll(x => x.Name.Equals(hintName, StringComparison.OrdinalIgnoreCase));
    }

    string ReplaceSpecialTokens(string input)
    {
        // Replace {input:<inputname>} with the key bound to that input
        input = Regex.Replace(input, @"{input:([^}]+)}", match =>
        {
            string key = match.Groups[1].Value.Trim();
            return $"<span class=\"key\"> {Input.GetButtonOrigin(key)} </span>";
        });
        return input;
    }
}