//	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.Data;

namespace Spludlow
{
	/// <summary>
	/// Simple Persistant varible storage (per host). For thread safty do get() and set() inside using{}, see test methods below
	/// </summary>
	public class Variables : IDisposable
	{
		private Spludlow.Data.LockedTextTable _LockedTextTable;

		private static string Filename = Spludlow.Config.ProgramData + @"\Data\Variables.txt";

		private static DataTable _EmptyTable = Spludlow.Data.TextTable.ReadText(new string[]
		{
			"Key		Value",
			"String*	String",
		});

		private static Spludlow.Data.LockedTextTable MakeLockedTable()
		{
			return new Data.LockedTextTable(Filename, false, Encoding.UTF8, false, _EmptyTable);
		}

		public Variables()
		{
			this._LockedTextTable = MakeLockedTable();
		}

		public void Set(string key, string value)
		{
			DataRow row = this._LockedTextTable.Table.Rows.Find(key);
			if (row == null)
				row = this._LockedTextTable.Table.Rows.Add(key, value);
			else
				row["Value"] = value;
		}
		public static void SetValue(string key, string value)
		{
			using (Variables variables = new Variables())
				variables.Set(key, value);
		}

		public string Get(string key)
		{
			DataRow row = this._LockedTextTable.Table.Rows.Find(key);
			if (row == null)
				return null;
			else
				return (string)row["Value"];
		}
		public static string GetValue(string key)
		{
			using (Variables variables = new Variables())
				return variables.Get(key);
		}

		public void Dispose()
		{
			this._LockedTextTable.Dispose();
		}




		/// <summary>
		/// Bump up a number on seperate theads. Report is logged showing results with and without using{}.
		/// </summary>
		public static void Test()
		{
			string key = "VariablesTest";
			int threads = 8;
			int iterations = 8;
			int sleepMs = 100;

			DataSet dataSet = new DataSet();

			Spludlow.Variables.SetValue(key, "0");
			dataSet.Tables.Add(Test(key, threads, iterations, sleepMs, false));

			Spludlow.Variables.SetValue(key, "0");
			dataSet.Tables.Add(Test(key, threads, iterations, sleepMs, true));

			Spludlow.Log.Report("Variables Thread Test", dataSet);

		}
		private static DataTable Test(string key, int threads, int iterations, int sleepMs, bool rightWay)
		{
			DataTable table = Spludlow.Data.TextTable.ReadText(new string[]
			{
				"Thread	Pass	Value",
				"Int32	Int32	String",
			});
			table.TableName = (rightWay == true ? "Right Way" : "Wrong Way");

			Task[] tasks = new Task[threads];
			for (int index = 0; index < threads; ++index)
			{
				int threadId = index;
				tasks[index] = new Task(() => TestWork(key, iterations, threadId, sleepMs, table, rightWay));
			}

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

			Task.WaitAll(tasks);

			return table;
		}
		private static void TestWork(string key, int iterations, int threadId, int sleepMs, DataTable table, bool rightWay)
		{
			Random rand = new Random();

			for (int pass = 0; pass < iterations; ++pass)
			{
				string value;

				if (rightWay == true)
				{
					using (Spludlow.Variables variables = new Spludlow.Variables())
					{
						value = variables.Get(key);

						System.Threading.Thread.Sleep(rand.Next(sleepMs));

						value = (Int32.Parse(value) + 1).ToString();
						variables.Set(key, value);
					}
				}
				else
				{
					value = Spludlow.Variables.GetValue(key);

					System.Threading.Thread.Sleep(rand.Next(sleepMs));

					value = (Int32.Parse(value) + 1).ToString();
					Spludlow.Variables.SetValue(key, value);
				}

				table.Rows.Add(threadId, pass, value);
			}
		}
	}
}