//	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;
using System.Security.Cryptography;

using System.Data;

namespace Spludlow.Io
{
	public class DiskTest
	{
		public static void TestWrite(string[] volumes)
		{
			int passCount = 1;

			int fileSizeMeg = 16;

			DataTable table = Spludlow.Data.TextTable.ReadText(new string[] {
				"Volume	Action	Pass	Time		Took	Result",
				"String	String	Int32	DateTime	String	String",
			});

			Task[] tasks = new Task[volumes.Length];
			for (int index = 0; index < volumes.Length; ++index)
			{
				string volume = volumes[index];

				tasks[index] = new Task(() => TestWriteWorker(volume, passCount, fileSizeMeg, table));
			}
			for (int index = 0; index < tasks.Length; ++index)
			{
				if (index > 0)
					System.Threading.Thread.Sleep(1000);   //	Prevent format getting duplicate Volume Serial Number 
				tasks[index].Start();
			}
				
			Task.WaitAll(tasks);

			Spludlow.Log.Report("Disk Test Write", table);

		}
		public static void TestWriteWorker(string volume, int passCount, int fileSizeMeg, DataTable table)
		{
			string label = "TEST_" + volume[0];

			DateTime last;

			bool error = false;

			for (int pass = 0; pass < passCount; ++pass)
			{
				string result;

				last = DateTime.Now;
				try
				{
					result = Spludlow.Io.Format.FormatDisk(volume, null, label);
				}
				catch (Exception e)
				{
					result = e.Message;
					error = true;
				}
				lock (table)
				{
					table.Rows.Add(volume, "FORMAT", pass, DateTime.Now, Spludlow.Text.TimeTook(last), result);
				}
				if (error == true)
					break;

				last = DateTime.Now;
				try
				{
					result = FillRandom(volume + @"\", fileSizeMeg).ToString();
				}
				catch (Exception e)
				{
					result = e.Message;
					error = true;
				}
				lock (table)
				{
					table.Rows.Add(volume, "WRITE", pass, DateTime.Now, Spludlow.Text.TimeTook(last), result);
				}
				if (error == true)
					break;
			}
		}



		public static int FillRandom(string directory, int sizeMeg)
		{
			Random random = new Random();

			byte[] buffer = new byte[1024 * 1024];

			int count = 0;

			while (true)
			{
				SHA1 hash = new SHA1Managed();

				using (MemoryStream memoryStream = new MemoryStream())
				{
					using (CryptoStream cryStream = new CryptoStream(memoryStream, hash, CryptoStreamMode.Write))
					{
						for (int meg = 0; meg < sizeMeg; ++meg)
						{
							random.NextBytes(buffer);
							cryStream.Write(buffer, 0, buffer.Length);
						}

						cryStream.FlushFinalBlock();
					}

					string filename = directory + @"\" + Spludlow.Hashing.Hex(hash.Hash);

					try
					{
						File.WriteAllBytes(filename, memoryStream.ToArray());
						++count;
					}
					catch (IOException ee)
					{
						if ((uint)ee.HResult != 0x80070070)
							throw ee;

						File.Delete(filename);
						break;
					}
				}
			}

			return count;
		}

		public static void TestRead(string[] volumes)
		{
			int passCount = 1;

			int fileSizeMeg = 16;

			DataTable table = Spludlow.Data.TextTable.ReadText(new string[] {
				"Volume	Action	Pass	Time		Took	Result",
				"String	String	Int32	DateTime	String	String",
			});

			Task[] tasks = new Task[volumes.Length];
			for (int index = 0; index < volumes.Length; ++index)
			{
				string volume = volumes[index];

				tasks[index] = new Task(() => TestReadWorker(volume, passCount, fileSizeMeg, table));
			}

			foreach (Task task in tasks)
				task.Start();

			Task.WaitAll(tasks);

			Spludlow.Log.Report("Disk Test Read", table);

		}

		public static void TestReadWorker(string volume, int passCount, int fileSizeMeg, DataTable table)
		{

			DateTime last;

			bool error = false;

			for (int pass = 0; pass < passCount; ++pass)
			{
				string result;

				last = DateTime.Now;
				try
				{
					result = ReadRandom(volume + @"\");
				}
				catch (Exception e)
				{
					result = e.Message;
					error = true;
				}
				lock (table)
				{
					table.Rows.Add(volume, "READ", pass, DateTime.Now, Spludlow.Text.TimeTook(last), result);
				}
				if (error == true)
					break;
			}
		}

		public static string ReadRandom(string directory)
		{
			string[] filenames = Directory.GetFiles(directory);
			int count = 0;
			foreach (string filename in filenames)
			{
				byte[] data = File.ReadAllBytes(filename);
				if (Spludlow.Hashing.SHA1Hex(data) != Path.GetFileName(filename))
					break;

				++count;
			}

			if (count == filenames.Length)
				return count.ToString();

			return count + "/" + filenames.Length;
		}

	}
}