using System;
using System.Threading;
using System.Threading.Tasks;

namespace com.clusterrr.SemaphoreLock
{
    public static class SemaphoreSlimSimple
    {
        public static SemaphoreLock WaitDisposable(this SemaphoreSlim semaphore)
        {
            var l = new SemaphoreLock(semaphore);
            semaphore.Wait();
            //GC.KeepAlive(l);
            return l;
        }

        public static async Task<SemaphoreLock> WaitDisposableAsync(this SemaphoreSlim semaphore, CancellationToken cancellationToken = default)
        {
            var l = new SemaphoreLock(semaphore);
            await semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
            //GC.KeepAlive(l);
            return l;
        }
    }

    public class SemaphoreLock : IDisposable
    {
        readonly SemaphoreSlim lockedSemaphore;

        public SemaphoreLock(SemaphoreSlim lockedSemaphore)
        {
            this.lockedSemaphore = lockedSemaphore;
        }

        public void Dispose()
        {
            lockedSemaphore.Release();
        }
    }
}