using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using UnityEngine.Networking;
using System;

public class WebImageLoader : MonoBehaviour
{
    // 用于显示图片的UI RawImage组件
    public RawImage imageDisplay;

    // 成功加载回调
    public Action<Texture2D> OnLoadSuccess;

    // 加载失败回调
    public Action<string> OnLoadFailed;

    // 进度更新回调
    public Action<float> OnProgressChanged;

    void Start()
    {
    }

    /// <summary>
    /// 异步加载网络图片
    /// </summary>
    /// <param name="url">图片URL地址</param>
    public void LoadImageFromUrl(string url, RawImage rawImage, Action action = null)
    {
        StartCoroutine(LoadImageCoroutine(url, rawImage, action));
    }

    /// <summary>
    /// 异步加载网络图片，带超时设置
    /// </summary>
    /// <param name="url">图片URL地址</param>
    /// <param name="timeoutSeconds">超时时间（秒）</param>
    public void LoadImageFromUrl(string url, int timeoutSeconds)
    {
        StartCoroutine(LoadImageWithTimeoutCoroutine(url, timeoutSeconds));
    }

    /// <summary>
    /// 协程方式加载图片
    /// </summary>
    /// <param name="url">图片URL地址</param>
    private IEnumerator LoadImageCoroutine(string url, RawImage _imageDisplay, Action action = null)
    {
        if (string.IsNullOrEmpty(url))
        {
            Debug.LogError("图片URL不能为空");
            OnLoadFailed?.Invoke("图片URL不能为空");
            yield break;
        }
        Debug.Log("url:" + url);

        using (UnityWebRequest request = UnityWebRequestTexture.GetTexture(url))
        {
            // 添加请求头，模拟浏览器访问
            request.SetRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36");

            var operation = request.SendWebRequest();

            // 监听下载进度
            while (!operation.isDone)
            {
                float progress = operation.progress;
                OnProgressChanged?.Invoke(progress);
                yield return null;
            }

            OnProgressChanged?.Invoke(1f); // 下载完成

            if (request.result == UnityWebRequest.Result.ConnectionError ||
                request.result == UnityWebRequest.Result.ProtocolError)
            {
                Debug.LogError($"加载图片失败: {request.error}");
                OnLoadFailed?.Invoke(request.error);
                StopCoroutine(LoadImageCoroutine(url, _imageDisplay, action));
                StartCoroutine(LoadImageCoroutine(url, _imageDisplay, action));
            }
            else
            {
                Texture2D texture = ((DownloadHandlerTexture)request.downloadHandler).texture;

                if (texture != null)
                {
                    if (_imageDisplay != null)
                    {
                        _imageDisplay.texture = texture;
                    }

                    OnLoadSuccess?.Invoke(texture);
                    _imageDisplay.gameObject.SetActive(true);
                    action?.Invoke();
                    Debug.Log("图片加载成功");
                }
                else
                {
                    Debug.LogError("获取到的纹理为空");
                    OnLoadFailed?.Invoke("获取到的纹理为空");
                }
            }
        }
    }

    /// <summary>
    /// 带超时控制的协程加载
    /// </summary>
    /// <param name="url">图片URL地址</param>
    /// <param name="timeoutSeconds">超时时间（秒）</param>
    private IEnumerator LoadImageWithTimeoutCoroutine(string url, int timeoutSeconds)
    {
        if (string.IsNullOrEmpty(url))
        {
            Debug.LogError("图片URL不能为空");
            OnLoadFailed?.Invoke("图片URL不能为空");
            yield break;
        }

        using (UnityWebRequest request = UnityWebRequestTexture.GetTexture(url))
        {
            // 设置超时
            request.timeout = timeoutSeconds;

            // 添加请求头
            request.SetRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36");

            var operation = request.SendWebRequest();

            float startTime = Time.time;
            while (!operation.isDone)
            {
                if (Time.time - startTime > timeoutSeconds)
                {
                    Debug.LogError($"加载超时 ({timeoutSeconds}秒)");
                    OnLoadFailed?.Invoke($"加载超时 ({timeoutSeconds}秒)");
                    yield break;
                }

                float progress = operation.progress;
                OnProgressChanged?.Invoke(progress);
                yield return null;
            }

            OnProgressChanged?.Invoke(1f); // 下载完成

            if (request.result == UnityWebRequest.Result.ConnectionError ||
                request.result == UnityWebRequest.Result.ProtocolError)
            {
                Debug.LogError($"加载图片失败: {request.error}");
                OnLoadFailed?.Invoke(request.error);
            }
            else
            {
                Texture2D texture = ((DownloadHandlerTexture)request.downloadHandler).texture;

                if (texture != null)
                {
                    if (imageDisplay != null)
                    {
                        imageDisplay.texture = texture;
                    }

                    OnLoadSuccess?.Invoke(texture);
                    Debug.Log("图片加载成功");
                }
                else
                {
                    Debug.LogError("获取到的纹理为空");
                    OnLoadFailed?.Invoke("获取到的纹理为空");
                }
            }
        }
    }

    /// <summary>
    /// 直接加载图片并返回Texture2D（静态方法）
    /// </summary>
    /// <param name="url">图片URL地址</param>
    /// <param name="callback">回调函数，参数为Texture2D和错误信息</param>
    public static IEnumerator LoadTextureFromUrl(string url, Action<Texture2D, string> callback)
    {
        using (UnityWebRequest request = UnityWebRequestTexture.GetTexture(url))
        {
            // 添加请求头
            request.SetRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36");

            yield return request.SendWebRequest();

            if (request.result == UnityWebRequest.Result.ConnectionError ||
                request.result == UnityWebRequest.Result.ProtocolError)
            {
                callback(null, request.error);
            }
            else
            {
                Texture2D texture = ((DownloadHandlerTexture)request.downloadHandler).texture;
                callback(texture, null);
            }
        }
    }

    /// <summary>
    /// 将Texture2D转换为Sprite
    /// </summary>
    /// <param name="texture">输入纹理</param>
    /// <returns>生成的Sprite</returns>
    public static Sprite TextureToSprite(Texture2D texture)
    {
        if (texture == null) return null;

        Rect rect = new Rect(0, 0, texture.width, texture.height);
        Vector2 pivot = new Vector2(0.5f, 0.5f); // 中心点

        return Sprite.Create(texture, rect, pivot);
    }
}