using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

using System.Net;

using System.Windows.Forms;

namespace PCMDataImporter

{

    /// <summary>

    /// 封装了FTP的两个操作：下载文件Download()和获取FTP服务器上文件列表信息GetFileList()

    /// </summary>

    public class ftpOperater

    {

        private string ftpServerIP;

        private string ftpUser;

        private string ftpPwd;

        private SystemParaReader spReader;

        public ftpOperater()

        {

            spReader = new SystemParaReader();

            this.ftpServerIP = spReader.GetSysParaValue("ftpServer");

            this.ftpUser = spReader.GetSysParaValue("ftpUser");

            this.ftpPwd = spReader.GetSysParaValue("ftpPwd");

        }

        /// <summary>

        /// 获取ftp服务器上的文件信息

        /// </summary>

        /// <returns>存储了所有文件信息的字符串数组</returns>

        public string[] GetFileList()

        {

            string[] downloadFiles;

            StringBuilder result = new StringBuilder();

            FtpWebRequest reqFTP;

            try

            {

                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/"));

                reqFTP.UseBinary = true;

                reqFTP.Credentials = new NetworkCredential(ftpUser, ftpPwd);

                reqFTP.Method = WebRequestMethods.Ftp.ListDirectory;

                WebResponse response = reqFTP.GetResponse();

                StreamReader reader = new StreamReader(response.GetResponseStream());

                string line = reader.ReadLine();

                while (line != null)

                {

                    result.Append(line);

                    result.Append("\n");

                    line = reader.ReadLine();

                }

                result.Remove(result.ToString().LastIndexOf('\n'), 1);

                reader.Close();

                response.Close();

                return result.ToString().Split('\n');

            }

            catch (Exception ex)

            {

                System.Windows.Forms.MessageBox.Show("获取文件信息失败:"+ex.Message,"操作失败",MessageBoxButtons.OK,MessageBoxIcon.Error);

                downloadFiles = null;

                return downloadFiles;

            }

        }

        /// <summary>

        /// 获取FTP上指定文件的大小

        /// </summary>

        /// <param name="filename">文件名</param>

        /// <returns>文件大小</returns>

        public long GetFileSize(string filename)

        {

            FtpWebRequest reqFTP;

            long fileSize = 0;

            try

            {

                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + filename));

                reqFTP.Method = WebRequestMethods.Ftp.GetFileSize;

                reqFTP.UseBinary = true;

                reqFTP.Credentials = new NetworkCredential(ftpUser, ftpPwd);

                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();

                Stream ftpStream = response.GetResponseStream();

                fileSize = response.ContentLength;

                ftpStream.Close();

                response.Close();

            }

            catch (Exception ex)

            {

                MessageBox.Show("获取文件大小时，出现异常:\n" + ex.Message, "获取文件大小失败！", MessageBoxButtons.OK, MessageBoxIcon.Error);

            }

            return fileSize;

        }

        /// <summary>

        /// 实现ftp下载操作

        /// </summary>

        /// <param name="filePath">保存到本地的文件名</param>

        /// <param name="fileName">远程文件名</param>

        public void Download(string filePath, string fileName)

        {

            FtpWebRequest reqFTP;

            try

            {

                //filePath = <<The full path where the file is to be created.>>,

                //fileName = <<Name of the file to be created(Need not be the name of the file on FTP server).>>

                FileStream outputStream = new FileStream(filePath + "\\" + fileName, FileMode.Create);

                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + fileName));

                reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;

                reqFTP.UseBinary = true;

                reqFTP.Credentials = new NetworkCredential(ftpUser, ftpPwd);

                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();

                Stream ftpStream = response.GetResponseStream();

                long cl = response.ContentLength;

                int bufferSize = 2048;

                int readCount;

                byte[] buffer = new byte[bufferSize];

                readCount = ftpStream.Read(buffer, 0, bufferSize);

                while (readCount > 0)

                {

                    outputStream.Write(buffer, 0, readCount);

                    readCount = ftpStream.Read(buffer, 0, bufferSize);

                }

                ftpStream.Close();

                outputStream.Close();

                response.Close();

            }

            catch (Exception ex)

            {

                MessageBox.Show(ex.Message);

            }

        }

    }

}