using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;

namespace vCloud.GeneratePackages.Tool
{
    class FtpHelper
    {                                 
        private const int bufferSize = 8192;
        
        /* FTP Get */
        public static void Get(string remoteFile, string localFile, Action<long> procressCallback = null, string user = "anonymous", string pass = null)
        {
            try
            {
                /* Create an FTP Request */
                var ftpRequest = (FtpWebRequest)FtpWebRequest.Create(remoteFile);
                /* Log in to the FTP Server with the User Name and Password Provided */
                ftpRequest.Credentials = new NetworkCredential(user, pass);
                /* When in doubt, use these options */
                ftpRequest.UseBinary = true;
                ftpRequest.UsePassive = true;
                ftpRequest.KeepAlive = true;
                /* Specify the Type of FTP Request */
                ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;
                /* Establish Return Communication with the FTP Server */
                var ftpResponse = (FtpWebResponse)ftpRequest.GetResponse();
                /* Get the FTP Server's Response Stream */
                var ftpStream = ftpResponse.GetResponseStream();
                /* Open a File Stream to Write the Downloaded File */
                FileStream localFileStream = new FileStream(localFile, FileMode.Create);
                /* Buffer for the Downloaded Data */
                byte[] byteBuffer = new byte[bufferSize];
                int bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
                /* Download the File by Writing the Buffered Data Until the Transfer is Complete */
                try
                {
                    while (bytesRead > 0)
                    {
                        localFileStream.Write(byteBuffer, 0, bytesRead);
                        bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
                        procressCallback?.Invoke(localFileStream.Length);
                    }
                }
                catch (Exception ex) { Console.WriteLine(ex.ToString()); }
                /* Resource Cleanup */
                localFileStream.Close();
                ftpStream.Close();
                ftpResponse.Close();
                ftpRequest = null;
            }
            catch (Exception ex) { Console.WriteLine(ex.ToString()); }
            return;
        }

        /// <summary>
        /// get file list
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public static IList<string> GetFileList(string url, string user = "anonymous", string pass = null)
        {
            FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(url);
            ftpRequest.Credentials = new NetworkCredential(user, pass);
            ftpRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
            FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
            StreamReader streamReader = new StreamReader(response.GetResponseStream());

            List<string> directories = new List<string>();

            string line = streamReader.ReadLine();
            while (!string.IsNullOrEmpty(line))
            {
                directories.Add(line);
                line = streamReader.ReadLine();
            }

            streamReader.Close();
            return directories;
        }
    }
}