using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;
using System.Threading.Tasks;


public class ImageLoader : MonoBehaviour
{
    // 缓存字典
    private Dictionary<string, Sprite> imageCache = new Dictionary<string, Sprite>();
    //private async void Start()
    //{
    //    GetComponent<Image>().sprite = await LoadImageAsync("https://fantasymonster-app.oss-cn-hangzhou.aliyuncs.com/goods/mall/c7860d8909194d479b6f27ccb922e863.png");
    //}
    // 异步加载图片
    public async Task<Sprite> LoadImageAsync(string url)
    {
        // 如果缓存中已经有图片，则直接返回缓存的图片
        if (imageCache.ContainsKey(url))
        {
            Debug.Log("Image found in cache.");
            return imageCache[url];
        }

        // 如果缓存中没有图片，则异步加载
        using (UnityWebRequest webRequest = UnityWebRequestTexture.GetTexture(url))
        {
            // 等待请求完成
            //await webRequest.SendWebRequest().ToTask();
            // 发送请求并等待响应
            var operation = webRequest.SendWebRequest();
            while (!operation.isDone)
                await Task.Yield(); // 等待请求完成，使用await以非阻塞的方式处理
            // 检查请求是否成功
            if (webRequest.result == UnityWebRequest.Result.Success)
            {
                // 获取下载的纹理
                Texture2D texture = ((DownloadHandlerTexture)webRequest.downloadHandler).texture;

                // 将纹理缓存
                imageCache[url] = TextureToSprite(texture);
                return imageCache[url];
            }
            else
            {
                Debug.LogError("Failed to load image: " + webRequest.error);
                return null;
            }
        }
    }
    // 将Texture2D转换为Sprite
    Sprite TextureToSprite(Texture2D texture)
    {
        // 使用纹理的尺寸创建一个Sprite
        return Sprite.Create(texture, new Rect(0, 0, texture.width, texture.height), new Vector2(0.5f, 0.5f));
    }
    // 加载并显示图片
    //public async void LoadAndDisplayImage(string url, Renderer renderer)
    //{
    //    Texture2D texture = await LoadImageAsync(url);
    //    if (texture != null)
    //    {
    //        renderer.material.mainTexture = texture;
    //    }
    //}
}