using UnityEngine;
using System.Collections.Generic;

public class FadeAlphaController : MonoBehaviour
{
    [Header("Fade Settings")]
    [Tooltip("Animation curve to control fade alpha over time (0-1)")]
    public AnimationCurve fadeCurve = AnimationCurve.Linear(0f, 1f, 1f, 0f);
    
    [Tooltip("Duration of the fade animation in seconds")]
    [Range(0.1f, 10f)]
    public float duration = 1f;
    
    [Tooltip("Auto play on start")]
    public bool autoPlay = false;
    
    [Tooltip("Loop the animation")]
    public bool loop = false;
    
    [Header("Material Settings")]
    [Tooltip("Shader property name for fade alpha")]
    public string fadeAlphaPropertyName = "_fadeAlpha";
    
    [Header("Runtime Info")]
    [SerializeField]
    [Tooltip("Current time in the animation")]
    private float currentTime = 0f;
    
    [SerializeField]
    [Tooltip("Is the animation currently playing")]
    private bool isPlaying = false;
    
    [Tooltip("初始 alpha")]
    public float initialAlpha = 0f; 

    private List<Material> cachedMaterials = new List<Material>();
    private int fadeAlphaPropertyID;
    
    private void Awake()
    {

        fadeAlphaPropertyID = Shader.PropertyToID(fadeAlphaPropertyName);
        CacheMaterials();
        ApplyFadeAlpha(initialAlpha);
    }
    
    private void Start()
    {
        if (autoPlay)
        {
            Play();
        }
    }
    
    private void Update()
    {
        if (isPlaying)
        {
            currentTime += Time.deltaTime;

            float normalizedTime = Mathf.Clamp01(currentTime / duration);

            float fadeValue = fadeCurve.Evaluate(normalizedTime);

            ApplyFadeAlpha(fadeValue);

            if (currentTime >= duration)
            {
                if (loop)
                {
                    currentTime = 0f;
                }
                else
                {
                    isPlaying = false;
                    currentTime = duration;
                }
            }
        }
    }
    

    private void CacheMaterials()
    {
        cachedMaterials.Clear();

        SkinnedMeshRenderer[] skinnedRenderers = GetComponentsInChildren<SkinnedMeshRenderer>(true);
        
        foreach (SkinnedMeshRenderer renderer in skinnedRenderers)
        {
            if (renderer != null && renderer.sharedMaterials != null)
            {
                foreach (Material mat in renderer.sharedMaterials)
                {
                    if (mat != null && mat.HasProperty(fadeAlphaPropertyID))
                    {
                        cachedMaterials.Add(mat);
                    }
                }
            }
        }

        MeshRenderer[] meshRenderers = GetComponentsInChildren<MeshRenderer>(true);
        
        foreach (MeshRenderer renderer in meshRenderers)
        {
            if (renderer != null && renderer.sharedMaterials != null)
            {
                foreach (Material mat in renderer.sharedMaterials)
                {
                    if (mat != null && mat.HasProperty(fadeAlphaPropertyID))
                    {
                        cachedMaterials.Add(mat);
                    }
                }
            }
        }
        
        Debug.Log($"[FadeAlphaController] Cached {cachedMaterials.Count} materials with {fadeAlphaPropertyName} property");
    }
    

    private void ApplyFadeAlpha(float alpha)
    {
        foreach (Material mat in cachedMaterials)
        {
            if (mat != null)
            {
                mat.SetFloat(fadeAlphaPropertyID, alpha);
            }
        }
    }

    public void Play()
    {
        currentTime = 0f;
        isPlaying = true;
    }

    public void Pause()
    {
        isPlaying = false;
    }

    public void Resume()
    {
        isPlaying = true;
    }

    public void Stop()
    {
        isPlaying = false;
        currentTime = 0f;
        ApplyFadeAlpha(fadeCurve.Evaluate(0f));
    }

    public void SetFadeAlpha(float alpha)
    {
        ApplyFadeAlpha(Mathf.Clamp01(alpha));
    }

    public void RefreshMaterials()
    {
        CacheMaterials();
    }

    public float GetCurrentFadeAlpha()
    {
        float normalizedTime = Mathf.Clamp01(currentTime / duration);
        return fadeCurve.Evaluate(normalizedTime);
    }
    
    private void OnValidate()
    {
        if (duration <= 0f)
        {
            duration = 0.1f;
        }
    }
    
    private void OnDestroy()
    {
        cachedMaterials.Clear();
    }
}