//	Spludlow Software
//	Copyright © Samuel P. Ludlow 2020 All Rights Reserved
//	Distributed under the terms of the GNU General Public License version 3
//	Distributed WITHOUT ANY WARRANTY; without implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE
//	https://www.spludlow.co.uk/LICENCE.TXT
//	The Spludlow logo is a registered trademark of Samuel P. Ludlow and may not be used without permission
//	v1.14

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

using System.Net;
using System.IO;
using System.Data;

namespace Spludlow.Net
{
	public class Ftp
	{
		//	active		ports need to open on client
		//	passive		default		all ports on server
		
		private int BufferSize = 1024 * 1024;

		private string Key;

		private NetworkCredential NetworkCredential;

		private bool UsePassive;
		private bool EnableSsl;

		private string Address;
		private string ConnectionGroupName;

		public Ftp(string key)
		{
			this.Key = key;
			
			NetworkCredential credential = Spludlow.Credentials.GetCredential(this.Key);

			string host = credential.Domain;

			this.UsePassive = true;
			this.EnableSsl = false;

			int trim = 0;

			if (host.Contains("*") == true)
			{
				this.UsePassive = false;
				++trim;
			}

			if (host.Contains("$") == true)
			{
				this.EnableSsl = true;
				++trim;
			}

			host = host.Substring(0, host.Length - trim);

			this.NetworkCredential = new NetworkCredential(credential.UserName, credential.Password);

			this.Address = "ftp://" + host;

			if (this.EnableSsl == true)
				Spludlow.WebServices.SetServerCertificateValidation();
		}

		public Ftp(string host, string userName, string password, bool activeMode, bool secure)
		{
			this.NetworkCredential = new NetworkCredential(userName, password);

			this.UsePassive = !activeMode;
			this.EnableSsl = secure;

			this.Address = "ftp://" + host;

			if (this.EnableSsl == true)
				Spludlow.WebServices.SetServerCertificateValidation();
		}

		private FtpWebRequest MakeRequest(string path, string method, bool useBinary)
		{
			if (path != null && path[0] != '/')
				throw new ApplicationException("FTP, Please supply an absolute FTP Path:\t" + path);

			if (this.ConnectionGroupName == null)
				this.ConnectionGroupName = this.Address + "/" + this.NetworkCredential.UserName;

			FtpWebRequest request = (FtpWebRequest)WebRequest.Create(this.Address + path);

			request.Method = method;
			request.Credentials = this.NetworkCredential;
			request.UsePassive = this.UsePassive;
			request.UseBinary = useBinary;

			request.KeepAlive = true;
			request.ConnectionGroupName = this.ConnectionGroupName;

			request.EnableSsl = this.EnableSsl;

			return request;
		}

		public string[] ListDirectory(string directory)
		{
			FtpWebRequest request = this.MakeRequest(directory, WebRequestMethods.Ftp.ListDirectory, false);

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

			using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
			{
				using (StreamReader reader = new StreamReader(response.GetResponseStream()))
				{
					string line = null;
					while ((line = reader.ReadLine()) != null)
						list.Add(line);
				}
			}

			list.Sort();
			return list.ToArray();
		}

		public string[] ListDirectoryDetails(string directory)
		{
			FtpWebRequest request = this.MakeRequest(directory, WebRequestMethods.Ftp.ListDirectoryDetails, false);

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

			using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
			{
				using (StreamReader reader = new StreamReader(response.GetResponseStream()))
				{
					string line = null;
					while ((line = reader.ReadLine()) != null)
						list.Add(line);
				}
			}

			return list.ToArray();
		}

		public static DataTable ParseDirectoryDetailsUNIX(string[] directoryListings)
		{
			DateTime lookTime = DateTime.Now;

			DataTable table = Spludlow.Data.TextTable.ReadText(new string[]
			{
				"FullName	LastWriteTime	Length	IsDirectory",
				"String		DateTime		Int64	Boolean",
			});

			foreach (string line in directoryListings)
			{
				string[] words = Spludlow.Text.Split(line, ' ', true, false, 9);

				if (words.Length != 9)
					throw new ApplicationException("ParseDirectoryDetailsUnix; Bad word count in directory line:\t" + line);

				long fileLength = Int64.Parse(words[4]);

				DateTime lastWriteTime;

				if (words[6].Length == 1)
					words[6] = "0" + words[6];

				if (words[7].Contains(":") == true)
				{
					//	Sep 10 11:48
					lastWriteTime = DateTime.ParseExact(words[5] + " " + words[6] + " " + lookTime.Year + " " + words[7], "MMM dd yyyy HH:mm", System.Globalization.CultureInfo.InvariantCulture);

					if (lastWriteTime > lookTime)
						lastWriteTime = lastWriteTime.AddYears(-1);
				}
				else
				{
					//	Jun 25  2006
					lastWriteTime = DateTime.ParseExact(words[5] + " " + words[6] + " " + words[7], "MMM dd yyyy", System.Globalization.CultureInfo.InvariantCulture);
				}

				bool isDirectory = false;
				if (words[0][0] == 'd')
					isDirectory = true;

				table.Rows.Add(new object[] { words[8], lastWriteTime, fileLength, isDirectory });
			}

			return table;
		}

		public void DeleteFile(string filename)
		{
			FtpWebRequest request = this.MakeRequest(filename, WebRequestMethods.Ftp.DeleteFile, false);
			FtpWebResponse response = (FtpWebResponse)request.GetResponse();
			response.Dispose();
		}

		public void RemoveDirectory(string directory)
		{
			FtpWebRequest request = this.MakeRequest(directory, WebRequestMethods.Ftp.RemoveDirectory, false);
			FtpWebResponse response = (FtpWebResponse)request.GetResponse();
			response.Dispose();
		}

		public void MakeDirectory(string directory)
		{
			FtpWebRequest request = this.MakeRequest(directory, WebRequestMethods.Ftp.MakeDirectory, false);
			FtpWebResponse response = (FtpWebResponse)request.GetResponse();
			response.Dispose();
		}

		public long GetFileSize(string filename)
		{
			FtpWebRequest request = this.MakeRequest(filename, WebRequestMethods.Ftp.GetFileSize, false);

			try
			{
				using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
					return response.ContentLength;
			}
			catch (WebException ee)
			{
				FtpWebResponse response = (FtpWebResponse)ee.Response;
				if (response.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable)
					return 0;

				throw ee;
			}
		}

		public bool FileExists(string filename)
		{
			FtpWebRequest request = this.MakeRequest(filename, WebRequestMethods.Ftp.GetFileSize, false);

			try
			{
				FtpWebResponse response = (FtpWebResponse)request.GetResponse();
				response.Dispose();
				return true;
			}
			catch (WebException ee)
			{
				FtpWebResponse response = (FtpWebResponse)ee.Response;
				if (response.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable)
					return false;

				throw ee;
			}
		}

		public void DownloadFile(string ftpFilename, string localFilename)
		{
			byte[] buffer = new byte[this.BufferSize];

			FtpWebRequest request = this.MakeRequest(ftpFilename, WebRequestMethods.Ftp.DownloadFile, true);

			using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
			{
				using (Stream responseStream = response.GetResponseStream())
				{
					using (FileStream fileStream = new FileStream(localFilename, FileMode.Create))
					{
						int count;
						while ((count = responseStream.Read(buffer, 0, buffer.Length)) > 0)
							fileStream.Write(buffer, 0, count);
					}
				}
			}
		}

		public void UploadText(string text, string ftpFilename)
		{
			byte[] buffer = Spludlow.Text.GetBytes(text);

			FtpWebRequest request = this.MakeRequest(ftpFilename, WebRequestMethods.Ftp.UploadFile, true);

			using (Stream requestStream = request.GetRequestStream())
			{
				requestStream.Write(buffer, 0, buffer.Length);
			}

			FtpWebResponse response = (FtpWebResponse)request.GetResponse();
			response.Dispose();
		}

		public void UploadFile(string localFilename, string ftpFilename)
		{
			byte[] buffer = new byte[this.BufferSize];

			FtpWebRequest request = this.MakeRequest(ftpFilename, WebRequestMethods.Ftp.UploadFile, true);

			using (FileStream fileStream = new FileStream(localFilename, FileMode.Open))
			{
				using (Stream requestStream = request.GetRequestStream())
				{
					int count;
					while ((count = fileStream.Read(buffer, 0, buffer.Length)) > 0)
						requestStream.Write(buffer, 0, count);
				}
			}

			FtpWebResponse response = (FtpWebResponse)request.GetResponse();
			response.Dispose();
		}

		public long AppendFile(string localFilename, string ftpFilename)
		{
			long localSize = Spludlow.Io.Files.FileLength(localFilename);
			long ftpSize = this.GetFileSize(ftpFilename);
			long transfered = 0;

			if (ftpSize == localSize)
				return 0;

			if (ftpSize > localSize)
				throw new ApplicationException("FTP Append, FTP File size is greater than local file size:\t" + localFilename + ", " + ftpSize);

			byte[] buffer = new byte[this.BufferSize];

			FtpWebRequest request = this.MakeRequest(ftpFilename, WebRequestMethods.Ftp.AppendFile, true);

			using (FileStream fileStream = new FileStream(localFilename, FileMode.Open))
			{
				fileStream.Seek(ftpSize, SeekOrigin.Begin);

				using (Stream requestStream = request.GetRequestStream())
				{
					int count;
					while ((count = fileStream.Read(buffer, 0, buffer.Length)) > 0)
					{
						requestStream.Write(buffer, 0, count);
						transfered += count;
					}
				}
			}

			FtpWebResponse response = (FtpWebResponse)request.GetResponse();
			response.Dispose();

			return transfered;
		}

		public int DownloadDirectory(string ftpDirectory, string localDirectory)
		{
			List<string> ftpFilenames = new List<string>();
			foreach (string filename in this.ListDirectory(ftpDirectory))
				ftpFilenames.Add(Path.GetFileName(filename));

			List<string> localFilenames = new List<string>();
			foreach (string filename in Directory.GetFiles(localDirectory))
				localFilenames.Add(Path.GetFileName(filename));

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

			foreach (string ftpFilename in ftpFilenames)
			{
				if (localFilenames.Contains(ftpFilename) == false)
					downloadFilenames.Add(ftpFilename);
			}

			int goneCount = 0;
			int gotCount = 0;
			foreach (string localFilename in localFilenames)
			{
				if (ftpFilenames.Contains(localFilename) == false)
					++goneCount;
				else
					++gotCount;
			}

			foreach (string filename in downloadFilenames)
			{
				string ftpFilename = ftpDirectory + "/" + filename;
				string localFilename = localDirectory + @"\" + filename;

				this.DownloadFile(ftpFilename, localFilename);
			}

			Spludlow.Log.Info("FTP, Download Directory:" + this.Key +
				", Ftp:" + ftpFilenames.Count + ", Local:" + localFilenames.Count + ", Download:" + downloadFilenames.Count + ", Gone:" + goneCount + ", Got:" + gotCount);

			return downloadFilenames.Count;
		}

		public int UploadDirectory(string localDirectory, string ftpDirectory)
		{
			List<string> localFilenames = new List<string>();
			foreach (string filename in Directory.GetFiles(localDirectory))
				localFilenames.Add(Path.GetFileName(filename));

			List<string> ftpFilenames = new List<string>();
			foreach (string filename in this.ListDirectory(ftpDirectory))
				ftpFilenames.Add(Path.GetFileName(filename));

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

			foreach (string localFilename in localFilenames)
			{
				if (ftpFilenames.Contains(localFilename) == false)
					uploadFilenames.Add(localFilename);
			}

			foreach (string filename in uploadFilenames)
			{
				string localFilename = localDirectory + @"\" + filename;
				string ftpFilename = ftpDirectory + "/" + filename;

				this.UploadFile(localFilename, ftpFilename);
			}

			Spludlow.Log.Info("FTP, Upload Directory:" + this.Key +
				", Ftp:" + ftpFilenames.Count + ", Local:" + localFilenames.Count + ", Upload:" + uploadFilenames.Count);

			return uploadFilenames.Count;
		}

	}
}