//	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.IO;

namespace Spludlow.Io
{
	public class FsLinks
	{
		public static void LinkFile(string link, string target)
		{
			LinkFiles(new string[][] { new string[] { link, target } }, false, null);
		}

		public static void LinkFiles(string[][] linkTargetFilenames)
		{
			LinkFiles(linkTargetFilenames, false, null);
		}

		/// <summary>
		/// target can be relative path if originDirectory supplied
		/// link should always use full path
		/// </summary>
		/// <param name="targetLinkFilenames"></param>
		/// <param name="hard"></param>
		/// <param name="originDirectory"></param>
		/// <returns></returns>
		public static void LinkFiles(string[][] linkTargetFilenames, bool hard, string originDirectory)
		{
			string flag = hard ? "/H " : "";
			List<string> linkDirectories = new List<string>();

			StringBuilder batch = new StringBuilder();

			for (int index = 0; index < linkTargetFilenames.Length; ++index)
			{
				string link = linkTargetFilenames[index][0];
				string target = linkTargetFilenames[index][1];

				string linkDirectory = Path.GetDirectoryName(link);
				if (linkDirectories.Contains(linkDirectory) == false)
					linkDirectories.Add(linkDirectory);

				//	Escape characters, may be more
				link = link.Replace("%", "%%");

				batch.Append("mklink ");
				batch.Append(flag);
				batch.Append('\"');
				batch.Append(link);
				batch.Append("\" \"");
				batch.Append(target);
				batch.Append('\"');
				batch.AppendLine();
			}

			foreach (string linkDirectory in linkDirectories)
			{
				if (Directory.Exists(linkDirectory) == false)
					Directory.CreateDirectory(linkDirectory);
			}

			Spludlow.SpawnProcess.ProcessExitInfo info;

			using (Spludlow.TempDirectory tempDir = new TempDirectory())
			{
				string batchFilename = tempDir.Path + @"\link.bat";
				File.WriteAllText(batchFilename, batch.ToString(), new UTF8Encoding(false));

				string input = "chcp 65001" + Environment.NewLine + batchFilename + Environment.NewLine;

				info = Spludlow.SpawnProcess.Run("cmd.exe", null, originDirectory, null, 0, false, input, Encoding.UTF8);
			}

			//foreach (string[] linkTarget in linkTargetFilenames)
			//{
			//	if (File.Exists(linkTarget[0]) == false)
			//		Spludlow.Log.Error("Link Failure: " + linkTarget[0] + " -> " + linkTarget[1]);
			//}

			if (info.ExitCode != 0 || info.StandardError.Length > 0)
			{
				Spludlow.Log.Error("LinkFiles, StandardError, exit code: " + info.ExitCode, info.StandardError);
				Spludlow.Log.Error("LinkFiles, StandardOutput, exit code: " + info.ExitCode, info.StandardOutput);

				throw new ApplicationException("LinkFiles, exit code: " + info.ExitCode);
			}
		}

	}
}