using System.IO;
using Cysharp.Threading.Tasks;
using UnityEngine;
using YooAsset;

namespace HotMain.SHGame.YooAsset
{
    public class RemoteServices : IRemoteServices
    {
        private string defaultHostServer;
        private string fallbackHostServer;

        public RemoteServices(string defaultHostServer, string fallbackHostServer)
        {
            this.defaultHostServer = defaultHostServer;
            this.fallbackHostServer = fallbackHostServer;
        }

        public string GetRemoteMainURL(string fileName)
        {
            return $"{defaultHostServer}/{fileName}";
        }

        public string GetRemoteFallbackURL(string fileName)
        {
            return $"{fallbackHostServer}/{fileName}";
        }
    }
    
    /// <summary>
    /// 资源文件解密流
    /// </summary>
    public class BundleStream : FileStream
    {
        public const byte KEY = 64;

        public BundleStream(string path, FileMode mode, FileAccess access, FileShare share) : base(path, mode, access, share)
        {
        }

        public BundleStream(string path, FileMode mode) : base(path, mode)
        {
        }

        public override int Read(byte[] array, int offset, int count)
        {
            var index = base.Read(array, offset, count);
            for (int i = 0; i < array.Length; i++)
            {
                array[i] ^= KEY;
            }

            return index;
        }
    }
    
    
    /// <summary>
    /// 资源文件流加载解密类
    /// </summary>
    public class FileStreamDecryption : IDecryptionServices
    {
        /// <summary>
        /// 同步方式获取解密的资源包对象
        /// 注意：加载流对象在资源包对象释放的时候会自动释放
        /// </summary>
        AssetBundle IDecryptionServices.LoadAssetBundle(DecryptFileInfo fileInfo, out Stream managedStream)
        {
            BundleStream bundleStream = new BundleStream(fileInfo.FileLoadPath, FileMode.Open, FileAccess.Read, FileShare.Read);
            managedStream = bundleStream;
            return AssetBundle.LoadFromStream(bundleStream, fileInfo.ConentCRC, GetManagedReadBufferSize());
        }

        /// <summary>
        /// 异步方式获取解密的资源包对象
        /// 注意：加载流对象在资源包对象释放的时候会自动释放
        /// </summary>
        AssetBundleCreateRequest IDecryptionServices.LoadAssetBundleAsync(DecryptFileInfo fileInfo, out Stream managedStream)
        {
            BundleStream bundleStream = new BundleStream(fileInfo.FileLoadPath, FileMode.Open, FileAccess.Read, FileShare.Read);
            managedStream = bundleStream;
            return AssetBundle.LoadFromStreamAsync(bundleStream, fileInfo.ConentCRC, GetManagedReadBufferSize());
        }

        private static uint GetManagedReadBufferSize()
        {
            return 1024;
        }
    }
    
}