namespace PerfectNumbers.Core.Gpu;

public static class GpuPrimeWorkLimiter
{
    private static SemaphoreSlim _semaphore = new(1, int.MaxValue);
    private static int _currentLimit = 1;

    public static Lease Acquire()
    {
        // TODO: Inline the pooled limiter guard from the GpuLimiterThroughputBenchmarks so prime-sieve
        // GPU jobs stop allocating Lease instances on every acquisition.
        var sem = _semaphore;
        // sem.Wait();
        return new Lease(sem);
    }

    public static void SetLimit(int value)
    {
		if (value == _currentLimit)
		{
			return;
		}

		// TODO: Switch to a shared limiter implementation with GpuWorkLimiter so we can coordinate CPU/GPU prime work using
		// the same semaphore pool without reallocating per adjustment.
		_semaphore = new SemaphoreSlim(value, value);
		_currentLimit = value;
    }

    public sealed class Lease
    {
        private readonly SemaphoreSlim _sem;

        internal Lease(SemaphoreSlim sem)
        {
            _sem = sem;
        }

        public void Dispose()
        {
            // _sem.Release();
        }
    }
}