Syntriax.Engine/Engine.Systems/Tween/TweenExtensions.cs

using System;

namespace Engine.Systems.Tween;

public static class TweenExtensions
{
    private static readonly System.Collections.Generic.Dictionary<ITween, int> loopDictionary = [];

    public static ITween Loop(this ITween tween, int count)
    {
        if (!loopDictionary.TryAdd(tween, count))
            throw new($"Tween already has a loop in progress.");

        tween.OnCompleted.AddListener(looperDelegate);
        tween.OnEnded.AddListener(looperEndDelegate);

        return tween;
    }

    private static readonly Core.Event<ITween>.EventHandler looperEndDelegate = sender => loopDictionary.Remove(sender);
    private static readonly Core.Event<ITween>.EventHandler looperDelegate = sender =>
    {
        int counter = loopDictionary[sender] = loopDictionary[sender] - 1;

        if (counter <= 0)
        {
            loopDictionary.Remove(sender);
            return;
        }

        Tween tweenConcrete = (Tween)sender;
        tweenConcrete.Reset();
        tweenConcrete.State = TweenState.Playing;
    };

    public static ITween LoopInfinitely(this ITween tween)
    {
        tween.OnCompleted.AddListener(repeaterDelegate);
        return tween;
    }

    private static readonly Core.Event<ITween>.EventHandler repeaterDelegate = sender =>
    {
        Tween tweenConcrete = (Tween)sender;
        tweenConcrete.Reset();
        tweenConcrete.State = TweenState.Playing;
    };

    public static ITween Ease(this ITween tween, IEasing easing)
    {
        Tween tweenConcrete = (Tween)tween;
        tweenConcrete.Easing = easing;

        return tween;
    }

    public static ITween OnStart(this ITween tween, Action callback)
    {
        tween.OnStarted.AddListener(_ => callback.Invoke());
        return tween;
    }

    public static ITween OnPause(this ITween tween, Action callback)
    {
        tween.OnPaused.AddListener(_ => callback.Invoke());
        return tween;
    }

    public static ITween OnResume(this ITween tween, Action callback)
    {
        tween.OnResumed.AddListener(_ => callback.Invoke());
        return tween;
    }

    public static ITween OnCancel(this ITween tween, Action callback)
    {
        tween.OnCancelled.AddListener(_ => callback.Invoke());
        return tween;
    }

    public static ITween OnComplete(this ITween tween, Action callback)
    {
        tween.OnCompleted.AddListener(_ => callback.Invoke());
        return tween;
    }

    public static ITween OnEnd(this ITween tween, Action callback)
    {
        tween.OnEnded.AddListener(_ => callback.Invoke());
        return tween;
    }

    public static ITween OnUpdate(this ITween tween, Action callback)
    {
        tween.OnUpdated.AddListener(_ => callback.Invoke());
        return tween;
    }

    public static ITween OnDeltaUpdate(this ITween tween, Action<float> callback)
    {
        tween.OnDeltaUpdated.AddListener((_, arguments) => callback.Invoke(arguments.Delta));
        return tween;
    }
}