using System.IO;
using UnityEngine;
using YooAsset;

namespace AlicizaX.Resource.Runtime
{
    internal partial class ResourceManager
    {
        /// <summary>
        /// 远端资源地址查询服务类
        /// </summary>
        private class RemoteServices : IRemoteServices
        {
            private readonly string _defaultHostServer;
            private readonly string _fallbackHostServer;

            public RemoteServices(string defaultHostServer, string fallbackHostServer)
            {
                _defaultHostServer = defaultHostServer;
                _fallbackHostServer = fallbackHostServer;
            }

            string IRemoteServices.GetRemoteMainURL(string fileName)
            {
                return $"{_defaultHostServer}/{fileName}";
            }

            string IRemoteServices.GetRemoteFallbackURL(string fileName)
            {
                return $"{_fallbackHostServer}/{fileName}";
            }
        }

           /// <summary>
        /// 资源文件流加载解密类
        /// </summary>
        private 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.FileLoadCRC, 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.FileLoadCRC, GetManagedReadBufferSize());
            }

            public byte[] ReadFileData(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

            public string ReadFileText(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

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

        /// <summary>
        /// 资源文件偏移加载解密类
        /// </summary>
        private class FileOffsetDecryption : 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)
            {
                managedStream = null;
                return AssetBundle.LoadFromFile(fileInfo.FileLoadPath, fileInfo.FileLoadCRC, GetFileOffset());
            }

            /// <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)
            {
                managedStream = null;
                return AssetBundle.LoadFromFileAsync(fileInfo.FileLoadPath, fileInfo.FileLoadCRC, GetFileOffset());
            }

            public byte[] ReadFileData(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

            public string ReadFileText(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

            private static ulong GetFileOffset()
            {
                return 32;
            }
        }
    


        /// <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;
            }
        }


        public class StreamingAssetsDefine
        {
            /// <summary>
            /// 根目录名称（保持和YooAssets资源系统一致）
            /// </summary>
            public const string RootFolderName = "package";
        }


#if UNITY_EDITOR
        internal class PreprocessBuild : UnityEditor.Build.IPreprocessBuildWithReport
        {
            public int callbackOrder
            {
                get { return 0; }
            }

            /// <summary>
            /// 在构建应用程序前处理
            /// 原理：在构建APP之前，搜索StreamingAssets目录下的所有资源文件，然后将这些文件信息写入内置清单，内置清单存储在Resources文件夹下。
            /// </summary>
            public void OnPreprocessBuild(UnityEditor.Build.Reporting.BuildReport report)
            {
                string saveFilePath = "Assets/AATemp/Resources/BuildinFileManifest.asset";
                if (File.Exists(saveFilePath))
                {
                    File.Delete(saveFilePath);
                    UnityEditor.AssetDatabase.SaveAssets();
                    UnityEditor.AssetDatabase.Refresh();
                }

                string folderPath = $"{Application.dataPath}/StreamingAssets/{StreamingAssetsDefine.RootFolderName}";
                DirectoryInfo root = new DirectoryInfo(folderPath);
                if (root.Exists == false)
                {
                    Debug.LogWarning($"没有发现YooAsset内置目录 : {folderPath}");
                    return;
                }

                var manifest = ScriptableObject.CreateInstance<BuildinFileManifest>();
                FileInfo[] files = root.GetFiles("*", SearchOption.AllDirectories);
                foreach (var fileInfo in files)
                {
                    if (fileInfo.Extension == ".meta")
                        continue;
                    if (fileInfo.Name.StartsWith("PackageManifest_"))
                        continue;

                    BuildinFileManifest.Element element = new BuildinFileManifest.Element();
                    element.PackageName = fileInfo.Directory.Name;
                    element.FileCRC32 = YooAsset.HashUtility.FileCRC32(fileInfo.FullName);
                    element.FileName = fileInfo.Name;
                    manifest.BuildinFiles.Add(element);
                }

                if (Directory.Exists("Assets/AATemp/Resources") == false)
                    Directory.CreateDirectory("Assets/AATemp/Resources");
                UnityEditor.AssetDatabase.CreateAsset(manifest, saveFilePath);
                UnityEditor.AssetDatabase.SaveAssets();
                UnityEditor.AssetDatabase.Refresh();
                Debug.Log($"一共{manifest.BuildinFiles.Count}个内置文件，内置资源清单保存成功 : {saveFilePath}");
            }
        }
#endif
    }
}