using UnityEngine;
using UnityEngine.UI;

[RequireComponent(typeof(Graphic))]
public class UIDissolveController : MonoBehaviour
{
    public Material materialTemplate;
    [Range(0f, 1f)]
    public float dissolveAmount = 1f;
    public float dissolveSpeed = 1f;
    public bool isDissolving;
    [ColorUsage(true, true)]
    public Color dissolveOutColor = Color.magenta;
    [ColorUsage(true, true)]
    public Color dissolveInColor = Color.white;

    private Graphic graphic;
    private Material runtimeMaterial;

    private static readonly int DissolveAmountId = Shader.PropertyToID("_DissolveAmount");
    private static readonly int DissolveColorId = Shader.PropertyToID("_DissolveColor");

    private void Awake()
    {
        graphic = GetComponent<Graphic>();
        EnsureRuntimeMaterial();
        ApplyProperties();
    }

    private void OnEnable()
    {
        EnsureRuntimeMaterial();
        ApplyProperties();
    }

    private void OnDestroy()
    {
        if (runtimeMaterial != null)
        {
            if (graphic != null && graphic.material == runtimeMaterial)
            {
                graphic.material = null;
            }
            Destroy(runtimeMaterial);
        }
    }

    private void Update()
    {
        if (runtimeMaterial == null)
        {
            return;
        }

        if (isDissolving)
        {
            dissolveAmount = Mathf.Max(0f, dissolveAmount - Time.deltaTime * dissolveSpeed);
            runtimeMaterial.SetColor(DissolveColorId, dissolveOutColor);
        }
        else
        {
            dissolveAmount = Mathf.Min(1f, dissolveAmount + Time.deltaTime * dissolveSpeed);
            runtimeMaterial.SetColor(DissolveColorId, dissolveInColor);
        }

        runtimeMaterial.SetFloat(DissolveAmountId, dissolveAmount);
    }

    public void SetDissolveAmount(float value)
    {
        dissolveAmount = Mathf.Clamp01(value);
        ApplyProperties();
    }

    public void DissolveOut()
    {
        isDissolving = true;
        ApplyProperties();
    }

    public void DissolveIn()
    {
        isDissolving = false;
        ApplyProperties();
    }

    private void EnsureRuntimeMaterial()
    {
        if (graphic == null)
        {
            graphic = GetComponent<Graphic>();
        }

        if (graphic == null)
        {
            return;
        }

        Material source = materialTemplate != null
            ? materialTemplate
            : (graphic.material != null ? graphic.material : graphic.defaultMaterial);
        if (source == null)
        {
            return;
        }

        if (runtimeMaterial != null && runtimeMaterial.shader == source.shader)
        {
            if (graphic.material != runtimeMaterial)
            {
                graphic.material = runtimeMaterial;
            }
            return;
        }

        if (runtimeMaterial != null)
        {
            Destroy(runtimeMaterial);
        }

        runtimeMaterial = new Material(source);
        runtimeMaterial.name = source.name + " (UI Runtime)";
        graphic.material = runtimeMaterial;
    }

    private void ApplyProperties()
    {
        if (runtimeMaterial == null)
        {
            return;
        }

        runtimeMaterial.SetFloat(DissolveAmountId, dissolveAmount);
        runtimeMaterial.SetColor(DissolveColorId, isDissolving ? dissolveOutColor : dissolveInColor);
    }
}