using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace IStation.Untity 
{
    /// <summary>
    /// http文件辅助类
    /// </summary>
    public class HttpFileHelper
    {
        /// <summary>
        /// 上传文件
        /// </summary>
        public static string Upload(string url, string filePath)
        {
            if (string.IsNullOrEmpty(url))
                return default;
            if (string.IsNullOrEmpty(filePath))
                return default;
            if (!System.IO.File.Exists(filePath))
                return default;
            try
            {
                var fileInfo = new System.IO.FileInfo(filePath);
                string boundary = "----" + DateTime.Now.Ticks.ToString("x");// 边界符
                byte[] beginBoundaryBytes = Encoding.UTF8.GetBytes("--" + boundary + "\r\n");     // 边界符开始。【☆】右侧必须要有 \r\n 。
                byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n"); // 边界符结束。【☆】两侧必须要有 --\r\n 。

                var fileFormTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" + "Content-Type: application/octet-stream\r\n\r\n";//文件模板

                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
                request.Method = WebRequestMethods.Http.Post;
                request.AllowWriteStreamBuffering = false;
                //request.KeepAlive = true;
                request.Timeout = -1;

                long contentLength = 0;

                var fileFormItem = string.Format(fileFormTemplate, "file", fileInfo.Extension);
                byte[] fileFormItemBytes = Encoding.UTF8.GetBytes(fileFormItem);
                contentLength += beginBoundaryBytes.Length;
                contentLength += fileFormItemBytes.Length;

                var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
                contentLength += fileStream.Length;
                contentLength += endBoundaryBytes.Length;
                request.ContentLength = contentLength;
                var requestStream = request.GetRequestStream();
                requestStream.Write(beginBoundaryBytes, 0, beginBoundaryBytes.Length);
                requestStream.Write(fileFormItemBytes, 0, fileFormItemBytes.Length);

                //每次上传4M
                byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)fileStream.Length))];
                int bytesRead = 0;
                while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                {
                    requestStream.Write(buffer, 0, bytesRead);
                }
                requestStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);

                fileStream.Close();
                requestStream.Close();

                var response = request.GetResponse();
                string responsetext = string.Empty;
                using (Stream stream = response.GetResponseStream())
                using (StreamReader reader = new StreamReader(stream))
                {
                    responsetext = reader.ReadToEnd();
                }
                return responsetext;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        /// <summary>
        /// 文件上传
        /// </summary>
        public static string Upload(string url, Stream stream, string suffix)
        {
            if (string.IsNullOrEmpty(url))
                return default;
            if (stream == null)
                return default;
            try
            {
                string boundary = "----" + DateTime.Now.Ticks.ToString("x");// 边界符
                byte[] beginBoundaryBytes = Encoding.UTF8.GetBytes("--" + boundary + "\r\n");     // 边界符开始。【☆】右侧必须要有 \r\n 。
                byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n"); // 边界符结束。【☆】两侧必须要有 --\r\n 。

                var fileFormTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" + "Content-Type: application/octet-stream\r\n\r\n";//文件模板

                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
                request.Method = WebRequestMethods.Http.Post;
                request.AllowWriteStreamBuffering = false;
                //request.KeepAlive = true;
                request.Timeout = -1;

                long contentLength = 0;

                var fileFormItem = string.Format(fileFormTemplate, "file", suffix);
                byte[] fileFormItemBytes = Encoding.UTF8.GetBytes(fileFormItem);

                contentLength += beginBoundaryBytes.Length;
                contentLength += fileFormItemBytes.Length;
                //var fileStream = new FileStream(steam, FileMode.Open, FileAccess.Read);

                contentLength += stream.Length;
                contentLength += endBoundaryBytes.Length;
                request.ContentLength = contentLength;
                var requestStream = request.GetRequestStream();
                requestStream.Write(beginBoundaryBytes, 0, beginBoundaryBytes.Length);
                requestStream.Write(fileFormItemBytes, 0, fileFormItemBytes.Length);

                //每次上传4M
                byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)stream.Length))];
                int bytesRead = 0;
                while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0)
                {
                    requestStream.Write(buffer, 0, bytesRead);
                }
                requestStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);

                stream.Close();
                requestStream.Close();

                var response = request.GetResponse();
                string responsetext = string.Empty;
                using (Stream rs = response.GetResponseStream())
                using (StreamReader reader = new StreamReader(rs))
                {
                    responsetext = reader.ReadToEnd();
                }
                return responsetext;
            }
            catch (System.Exception ex)
            {
                throw ex;
            }

        }

        /// <summary>
        /// 下载文件
        /// </summary>
        public static Stream Download(string url)
        {
            var request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            request.ContentType = "application/json";
            //request.Timeout = 10 * 1000;//请求超时时间      
            using (var response = (HttpWebResponse)request.GetResponse())
            {
                if (response.StatusCode == HttpStatusCode.NoContent)
                    return null;
                var ms = new MemoryStream();
                response.GetResponseStream().CopyTo(ms);
                return ms;
            }
        }

        /// <summary>
        /// 下载文件
        /// </summary>
        public static void DownloadUri(string uri, string filePath)
        {
            var client = new System.Net.WebClient();
            client.DownloadFile(uri, filePath);
        }
         
    }
}