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

public class LoadDll2 
{
    private static string GetWebRequestPath(string asset)
    {
        var path = $"{Application.streamingAssetsPath}/{asset}";
        if (!path.Contains("://"))
        {
            path = "file://" + path;
        }
        return path;
    }
    static Dictionary<string, AssetBundle> ablist = new Dictionary<string, AssetBundle>();
    public static IEnumerator DownLoadAssets(Action<AssetBundle> callback)
    {
        if (ablist.ContainsKey("obe"))
        {
            callback.Invoke(ablist["obe"]);

            yield return null;
        }
        else
        {
            string dllPath = GetWebRequestPath("obe");
            Debug.Log($"start download asset:{dllPath}");
            UnityWebRequest www = UnityWebRequest.Get(dllPath);
            yield return www.SendWebRequest();

#if UNITY_2020_1_OR_NEWER
            if (www.result != UnityWebRequest.Result.Success)
            {
                Debug.Log(www.error);
            }
#else
        if (www.isHttpError || www.isNetworkError)
        {
            Debug.Log(www.error);
        }
#endif
            else
            {
                if (ablist.ContainsKey("obe"))
                {

                    callback.Invoke(ablist["obe"]);
                }
                else
                {
                    Debug.Log("assets===>" + "obe");
                    // Or retrieve results as binary data
                    byte[] assetData = www.downloadHandler.data;

                    AssetBundle ab = AssetBundle.LoadFromMemory(assetData);
                    ablist.Add("obe", ab);
                    callback.Invoke(ab);
                    UnityEngine.Object[] assets = ab.LoadAllAssets();
                    for (int i = 0; i < assets.Length; i++)
                    {
                        Debug.Log("assets===>" + assets[i].name);
                        yield return null;
                    }

                }

            }

        }
    }
}