using Cysharp.Threading.Tasks;
using System.Threading;
using UnityEngine;
using UnityEngine.UI;

public class ExitDisplay : MonoBehaviour
{
    [SerializeField] private CanvasGroup progressGroup;  
    [SerializeField] private Image bar;

    private bool groupVisible = false;
    private float progress;
    private CancellationTokenSource cts;

    public void SetProgress(float percent)
    {
        progress = percent;
    }

    private void Update()
    {
        if(!groupVisible && progress>0)
        {
            cts?.Cancel();
            cts?.Dispose();
            cts = new();

            SetVisibility(true, cts.Token).Forget();
        }
        if (groupVisible && progress == 0) 
        {
            cts?.Cancel();
            cts?.Dispose();
            cts = new();

            SetVisibility(false, cts.Token).Forget();
        }

        bar.fillAmount = progress;
    }

    private async UniTask SetVisibility(bool visible, CancellationToken token)
    {
        float targetAlpha = visible ? 1 : 0;
        groupVisible = visible;

        while(progressGroup.alpha != targetAlpha && !token.IsCancellationRequested)
        {
            progressGroup.alpha= Mathf.MoveTowards(progressGroup.alpha, targetAlpha, Time.deltaTime);
            await UniTask.Yield(PlayerLoopTiming.Update, token);
        }
    }
}