using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web;

namespace WebApi.Common
{
    public class FileProvider
    {
        /// <summary>
        /// 下载文件(路径下载)
        /// </summary>
        /// <param name="filePath">文件绝对路径</param>
        /// <param name="fileName">文件保存名称</param>
        public static void DownLoadFile(string filePath, string fileName)
        {
            if (System.IO.File.Exists(filePath))
            {

                if (HttpContext.Current.Request.UserAgent != null && HttpContext.Current.Request.UserAgent.ToUpper().IndexOf("FIREFOX", StringComparison.Ordinal) != -1)
                {
                    fileName = "=?UTF-8?B?" + Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(fileName)) + "?=";
                }
                else
                {
                    fileName = System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8);
                    if (fileName != null) fileName = fileName.Replace("+", "%20");
                }
                FileInfo fileInfo = new FileInfo(filePath);
                HttpContext.Current.Response.Clear();
                HttpContext.Current.Response.ClearContent();
                HttpContext.Current.Response.ClearHeaders();
                HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
                HttpContext.Current.Response.AddHeader("Content-Length", fileInfo.Length.ToString());
                HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");
                HttpContext.Current.Response.ContentType = "application/octet-stream";
                HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
                HttpContext.Current.Response.WriteFile(fileInfo.FullName);
                HttpContext.Current.Response.Flush();
                HttpContext.Current.Response.End();
            }
            else
            {
                HttpContext.Current.Response.Write("文件未找到");
                HttpContext.Current.Response.Flush();
                HttpContext.Current.Response.End();
            }
        }
        /// <summary>
        /// 文件下载(流下载)
        /// </summary>
        /// <param name="ms"></param>
        /// <param name="fileName"></param>
        public static void DownLoadFile(MemoryStream ms, string fileName)
        {
            if (ms != Stream.Null)
            {
                if (HttpContext.Current.Request.UserAgent != null && HttpContext.Current.Request.UserAgent.ToUpper().IndexOf("FIREFOX", StringComparison.Ordinal) != -1)
                {
                    fileName = "=?UTF-8?B?" + Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(fileName)) + "?=";
                }
                else
                {
                    fileName = System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8);
                    if (fileName != null) fileName = fileName.Replace("+", "%20");
                }
                HttpContext.Current.Response.Clear();
                HttpContext.Current.Response.ClearContent();
                HttpContext.Current.Response.ClearHeaders();
                HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment;filename=", fileName));
                HttpContext.Current.Response.AddHeader("Content-Length", ms.Length.ToString());
                HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");
                HttpContext.Current.Response.ContentType = "application/octet-stream;charset=utf-8";
                HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8;
                HttpContext.Current.Response.BinaryWrite(ms.ToArray());
                HttpContext.Current.Response.Flush();
                HttpContext.Current.Response.End();
                ms.Close();
                ms.Dispose();
            }
        }
        /// <summary>
        /// 文件下载(流下载)
        /// </summary>
        /// <param name="buffer"></param>
        /// <param name="fileName"></param>
        public static void DownLoadFile(byte[] buffer, string fileName)
        {
            if (HttpContext.Current.Request.UserAgent != null && HttpContext.Current.Request.UserAgent.ToUpper().IndexOf("FIREFOX", StringComparison.Ordinal) != -1)
            {
                fileName = "=?UTF-8?B?" + Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(fileName)) + "?=";
            }
            else
            {
                fileName = System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8);
                if (fileName != null) fileName = fileName.Replace("+", "%20");
            }
            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.ClearContent();
            HttpContext.Current.Response.ClearHeaders();
            HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}", fileName));
            HttpContext.Current.Response.AddHeader("Content-Length", buffer.Length.ToString());
            HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");
            HttpContext.Current.Response.ContentType = "application/octet-stream;charset=utf-8";
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8;
            HttpContext.Current.Response.BinaryWrite(buffer);
            HttpContext.Current.Response.Flush();
            HttpContext.Current.Response.End();
        }
    }
}