using UnityEngine;
using UnityEngine.UI;

public class UIFader : MonoBehaviour
{
    public float flashSpeed = 0.5f;     // 闪烁速度
    public float minAlpha = 0f;     // 最低透明度
    public float maxAlpha = 1f;       // 最高透明度

    private Image[] childImages;
    private bool flashing = false;

    void OnEnable()
    {
        // 只获取子物体上的 Image
        childImages = GetComponentsInChildren<Image>(true);
        childImages = System.Array.FindAll(childImages, img => img.gameObject != this.gameObject);

        flashing = true;
    }

    void OnDisable()
    {
        flashing = false;

        // 恢复透明度为 1
        if (childImages != null)
        {
            foreach (var img in childImages)
            {
                if (img != null)
                {
                    Color c = img.color;
                    c.a = 1f;
                    img.color = c;
                }
            }
        }
    }

    void Update()
    {
        if (!flashing || childImages == null) return;

        float alpha = Mathf.Lerp(minAlpha, maxAlpha, (Mathf.Sin(Time.time * flashSpeed) + 1f) / 2f);

        foreach (var img in childImages)
        {
            if (img != null)
            {
                Color c = img.color;
                c.a = alpha;
                img.color = c;
            }
        }
    }
}