using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using NLog;
using Renci.SshNet;
using Renci.SshNet.Common;

namespace Dfs.WayneChina.FairbanksRTData
{
    /// <summary>
    /// The SFTP client is implemented using SSH.NET 2016.1.0
    /// </summary>
    public class FairbanksSftpClient
    {
        #region Properties

        public string Host { get; private set; }

        public int Port { get; private set; }

        public string UserName { get; set; }

        public string Password { get; set; }

        public SftpClient Client { get; private set; }

        public bool Connected { get; set; } = false;

        #endregion

        #region Logger

        NLog.Logger logger = NLog.LogManager.LoadConfiguration("NLog.config").GetLogger("Fairbanks");

        #endregion

        #region Constructor

        public FairbanksSftpClient(string host, string username, string password)
        {
            RefreshConfig(host, username, password);
        }

        #endregion

        #region Refresh Config

        public void RefreshConfig(string host, string username, string password)
        {
            Host = host;
            UserName = username;
            Password = password;

            //Reset the connection
            Client = null;
            Connected = false;
        }

        #endregion

        #region Initialize

        public void Initialize()
        {
            if (Client != null)
                return;

            logger.Info($"Initializing SFTP client against: {Host}, {UserName}, {Password}");
            Client = new SftpClient(Host, 22, UserName, Password);
        }

        #endregion

        #region Connection (connect and disconnect)

        public void Connect()
        {
            Initialize(); //Ensure the client is initialized

            logger.Info($"** Connecting to SFTP host: {Host}");

            try
            {
                Client.Connect();

                Connected = true;
            }
            catch (SshOperationTimeoutException timeoutEx)
            {
                Connected = false;
                logger.Error("timeout: " + timeoutEx.ToString());
                Client.Disconnect();
            }
            catch (InvalidOperationException invOpEx)
            {
                if (invOpEx.Message.Contains("already connected"))
                {
                    logger.Error("Exception indicates client already connected, let's disconnect");
                    Client.Disconnect();
                    Connected = false;
                }
            }
            catch (Exception ex)
            {
                Connected = false;
                logger.Error(ex.ToString());
            }
        }

        public void Disconnect()
        {
            if (Connected && Client != null)
            {
                logger.Info("** Disconnecting from SFTP host");
                Client.Disconnect();
                Connected = false;
            }
        }

        #endregion

        #region Upload methods
        //Consider implementing an asynchronous method here.

        public bool UploadSingleFile(string fileName, string hostFolder)
        {
            try
            {
                logger.Info($"** Current SFTP client connected? {Connected}");

                Client.ChangeDirectory(hostFolder);
                using (var uplfileStream = File.OpenRead(fileName))
                {
                    Client.UploadFile(uplfileStream, Path.GetFileName(fileName), true);

                    logger.Info($"** Uploaded File: {fileName}");
                }

                return true;
            }
            catch (Exception ex)
            {
                logger.Error("Upload exception: " + ex.ToString());
                return false;
            }
        }

        public bool ConnectAndSend(string fileName, string hostFolder)
        {
            using (var sftp = new SftpClient(Host, 22, UserName, Password))
            {
                logger.Info($"** Connecting {Host}, port: 22, username: {UserName}, password: {Password}");

                try
                {
                    sftp.Connect();

                    logger.Info("** Connected");
                    sftp.ChangeDirectory(hostFolder);
                    using (var uplfileStream = File.OpenRead(fileName))
                    {
                        sftp.UploadFile(uplfileStream, Path.GetFileName(fileName), true);

                        logger.Info($"** Finished uploading - {fileName}");
                    }

                    sftp.Disconnect();
                    logger.Info("** Disconnected");

                    return true;
                }
                catch (Exception ex)
                {
                    logger.Error(ex.ToString());
                    return false;
                }
            }
        }

        #endregion
    }
}