using Sarand.Net.Standard.Base.Core;
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;

namespace Sarand.Net.Standard.Base.Tasks
{
	//=======================================================================
	public class SacsTaskData : SacsDisposable
	{
		//-------------------------------------------------------------------
		// Data members.
		// Cancellation token source - allows task cancellation to be triggered
		// if the cancellation token wasn't supplied on construction.
		private CancellationTokenSource cancellationTokenSource = null;

		//-------------------------------------------------------------------
		// Construction.
		public SacsTaskData (CancellationToken? cancellationToken = null)
		{
			if (cancellationToken != null)
			{
				// Cancell token supplied on construction
				// - cancellation is controlled by a higher level task.
				CancellationToken = (CancellationToken)cancellationToken;
			}
			else
			{
				// Cancellation token not supplied - cancellation can be triggered here.
				cancellationTokenSource = new CancellationTokenSource();
				CancellationToken = cancellationTokenSource.Token;
			}
		}
		protected override void Dispose (bool disposing)
		{
			if (disposing)
			{
				if (cancellationTokenSource != null)
				{
					cancellationTokenSource.Cancel();
					cancellationTokenSource.Dispose();
				}
				cancellationTokenSource = null;
			}
		}

		//-------------------------------------------------------------------
		// Properties.
		public bool Debug { get; set; }

		/// <summary>Token to allow the async request to be cancelled.</summary>
		public CancellationToken CancellationToken { get; }

		//-------------------------------------------------------------------
		//                      C a n c e l l a t i o n
		//-------------------------------------------------------------------

		/// <summary>Gets whether cancellation has been requested.</summary>
		public bool IsCancellationRequested { get { return CancellationToken.IsCancellationRequested; } }

		/// <summary>Throws a System.OperationCanceledException if this token has had cancellation requested.</summary>
		public void ThrowIfCancellationRequested()
		{
			CancellationToken.ThrowIfCancellationRequested();
		}

		/// <summary>Can cancellation be triggered here?</summary>
		public bool CanBeCancelled { get { return cancellationTokenSource != null; } }
		public bool TriggerCancellation ()
		{
			if (!CanBeCancelled) return false;
			cancellationTokenSource.Cancel();
			return true;
		}

		//-------------------------------------------------------------------
	}
	//=======================================================================
}