using System.IO;
using UnityEngine;

namespace AssetUpdate
{
    /// <summary>
    ///     获得服务器版本的AssetVersion
    /// </summary>
    public class AssetVersionAction : IAssetAsyncAction
    {
        private static string fileName
        {
            get
            {
                return AssetUtils.GetTextMd5(AssetConst.versionFile) + AssetConst.bundleVariant;
            }
        }
        private AssetUpdateDownloader _downloader;
        public AssetDependencyInfo mainInfo { get; private set; }
        public bool isEnd { get; private set; }
        public AssetUpdateManager.AssetUpdateError error { get; private set; }
        public int serverVersion { get; private set; }

        public bool UpdateTimeout()
        {
            return isEnd;
        }

        public void Dispose()
        {
            if (_downloader != null)
            {
                _downloader.Dispose();
                _downloader = null;
            }
        }

        public void Start(int version, string uri)
        {
            serverVersion = version;
            LoadAssetInfo();
            // 当前资源清单不存在或者过时
            if (mainInfo == null)
            {
                var oldUri = uri;
                uri = uri.Open(serverVersion.ToString()).Open(fileName);
                var path = AssetConst.persistentDataPath.Open(fileName);
                Debug.Log("Download version file from: " + uri + " url: " + oldUri);
                _downloader = new AssetUpdateDownloader(uri, path) {onComplete = OnComplete};
                _downloader.Start();
            }
            else
            {
                isEnd = true;
            }
        }

        private void OnComplete(AssetUpdateDownloader downloader)
        {
            isEnd = true;
            error = downloader.error;
            // 转换错误类型
            if (error != AssetUpdateManager.AssetUpdateError.FileCreateError
                && error != AssetUpdateManager.AssetUpdateError.Success)
                error = AssetUpdateManager.AssetUpdateError.VersionDataError;
            LoadAssetInfo();
            if (mainInfo == null || mainInfo.version != serverVersion)
            {
                error = AssetUpdateManager.AssetUpdateError.VersionDataError;
                Debug.LogError("Asset version info download complete, but still cannot get file under persistPath!");
            }
        }

        private void LoadAssetInfo()
        {
            var configPath = AssetConst.persistentDataPath.Open(fileName);
            if (File.Exists(configPath))
            {
                var persistInfo = AssetDependencyInfo.Create(configPath);
                if (persistInfo != null && persistInfo.version == serverVersion)
                    mainInfo = persistInfo;
            }
        }
    }
}