using System;
using System.IO;
using UnityEngine.Networking;
using XRTool.Util;

namespace MRStore.Util
{
    /// <summary>
    /// 断点下载的辅助器
    /// </summary>
    public class DownInfoHandler : DownloadHandlerScript
    {
        /// <summary>
        /// 文件流
        /// </summary>
        private FileStream stream;
        /// <summary>
        /// 下载资源的结构体
        /// </summary>
        public DownInfo info { get; private set; }
        public UnityWebRequest webRequest { get; private set; }
        public void SetWebRequest(UnityWebRequest req, long contentLength)
        {
            webRequest = req;
            ReadLocalData();
            if (info != null)
            {
                info.ActiveTotalLength((long)contentLength);
            }
        }
        /// <summary>
        /// 读取本地的数据
        /// 读取临时数据缓存区tmppath
        /// </summary>
        private void ReadLocalData()
        {
            if (stream == null)
            {
                try
                {
                    FileMode model = FileMode.Append;
                    if (!File.Exists(info.tmpFilePath))
                    {
                        model = FileMode.OpenOrCreate;
                    }
                    stream = new FileStream(info.tmpFilePath, model, FileAccess.Write, FileShare.Write);
                }
                catch (Exception ex)
                {
                    UnityLog.LogError(info.tmpFilePath + "File Stream Error" + ex.ToString());
                    if (stream != null)
                    {
                        stream.Dispose();
                    }
                    stream = null;
                }
            }
        }
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="info"></param>
        public DownInfoHandler(DownInfo info) : base(new byte[1024*256])
        {
            this.info = info;
            this.info.SetDownHandler(this);
        }
        /// <summary>
        /// 服务器返回此文件的剩余大小
        /// </summary>
        /// <param name="contentLength"></param>
        protected override void ReceiveContentLengthHeader(ulong contentLength)
        {
            if (contentLength == 0)
            {
                CompleteContent();
            }
            base.ReceiveContentLengthHeader(contentLength);
        }
        /// <summary>
        /// 从服务器接收到数据
        /// </summary>
        /// <param name="data"></param>
        /// <param name="dataLength"></param>
        /// <returns></returns>
        protected override bool ReceiveData(byte[] data, int dataLength)
        {
            WriteFile(data, dataLength);
            return base.ReceiveData(data, dataLength);
        }
        /// <summary>
        /// 下载，写入文件
        /// </summary>
        /// <param name="data"></param>
        /// <param name="dataLength"></param>
        public void WriteFile(byte[] data, int dataLength)
        {
            if (data != null && data.Length > 0)
            {
                if (stream != null)
                {
                    stream.Write(data, 0, dataLength);
                    info.ActiveProcess(GetProgress());
                }
            }
        }
        protected override float GetProgress()
        {
            return info.downloadedFileLen*1.0f / info.totalSize;
        }
        /// <summary>
        /// 下载完成
        /// 网络停止时也有可能会调用此方法
        /// </summary>
        protected override void CompleteContent()
        {
            if (stream != null)
            {
                stream.Flush();
                stream.Dispose();
            }
            stream = null;
            info.ActiveComplete();
            base.CompleteContent();
            Dispose();
        }
        /// <summary>
        /// 下载错误，程序异常退出，网络停止时等异常情况下，停止此资源
        /// </summary>
        public void ErrorDispose(string error)
        {
            if (stream != null)
            {
                stream.Flush();
                stream.Dispose();
            }
            if (info != null && !string.IsNullOrEmpty(error))
            {
                info.ActiveError(error);
            }
            stream = null;
            webRequest = null;
            Dispose();
        }
    }
}