//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="CancellableTask.cs"
//     Project: StgSharp
//     AuthorGroup: Nitload Space
//     Copyright (c) Nitload Space. All rights reserved.
//     
//     Permission is hereby granted, free of charge, to any person 
//     obtaining a copy of this software and associated documentation 
//     files (the “Software”), to deal in the Software without restriction, 
//     including without limitation the rights to use, copy, modify, merge,
//     publish, distribute, sublicense, and/or sell copies of the Software, 
//     and to permit persons to whom the Software is furnished to do so, 
//     subject to the following conditions:
//     
//     The above copyright notice and 
//     this permission notice shall be included in all copies 
//     or substantial portions of the Software.
//     
//     THE SOFTWARE IS PROVIDED “AS IS”, 
//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//     
//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace StgSharp.Threading
{
    internal class CancellableTask
    {

        private protected Action<CancellationToken> _startup;
        private protected Task taskInternal;
        private CancellationTokenSource cts;

        private protected CancellableTask()
        {
            cts = new CancellationTokenSource();
        }

        private protected CancellableTask(Action<CancellationToken> action)
        {
            taskInternal = new Task(InternalAction);
            cts = new CancellationTokenSource();
        }

        public bool IsCompleted
        {
            get => taskInternal.IsCompleted;
        }

        public CancellationTokenSource Cts
        {
            get => cts;
        }

        public int Id
        {
            get => taskInternal.Id;
        }

        public void Cancel()
        {
            Cts.Cancel();
        }

        public static CancellableTask Run(Action<CancellationToken> startup)
        {
            CancellableTask ret = new CancellableTask { _startup = startup };
            ret.taskInternal = Task.Run(ret.InternalAction);
            return ret;
        }

        public static void WaitAll(IEnumerable<CancellableTask> tasks)
        {
            IEnumerable<Task> convertedTasks = tasks.Select<CancellableTask, Task>
                (ct => ct.taskInternal);
            Task.WaitAll(convertedTasks.ToArray());
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        internal void InternalAction()
        {
            //Console.WriteLine($"Task {Task.CurrentId} is running.");
            _startup(Cts.Token);
        }

        public static implicit operator Task(CancellableTask task)
        {
            return task.taskInternal;
        }

        ~CancellableTask()
        {
            Cts.Dispose();
        }

    }
}