using System;
using BF;
using UnityEngine;
using UnityEngine.UI;

[RequireComponent(typeof(Image))]
public class UIResGhostTweenEffect : MonoBehaviour
{
    private Material mat;
    private float time;
    private Vector4[] offsets = new Vector4[3]
    { 
        new Vector4(-30, -30, 0, 0), 
        new Vector4(30, -30, 0, 0),  
        new Vector4(0, -60, 0, 0), 
    };

    public float smooth = .25f;

    private const float TWEEN_TIME = 1f;

    public void SetMaterial(Material material)
    {
        mat = material;
    }

    private void Awake()
    {
        time = TWEEN_TIME;
        var img = GetComponent<Image>();
        if (mat == null)
        {
            mat = new Material(Shader.Find("BF/UI/UIGhost"));
        }
        img.material = mat;
    }

    private void Update()
    {
        if (time > 0)
        {
            time -= Time.deltaTime;
            var lerp = (TWEEN_TIME - time) * smooth;
            offsets[0] = Vector4.Lerp(offsets[0], Vector4.zero, lerp);
            offsets[1] = Vector4.Lerp(offsets[1], Vector4.zero, lerp);
            offsets[2] = Vector4.Lerp(offsets[2], Vector4.zero, lerp);
            mat.SetVector("_Offset1", offsets[0]);
            mat.SetVector("_Offset2", offsets[1]);
            mat.SetVector("_Offset3", offsets[2]);
        }
    }

    private void OnDestroy()
    {
    }
}