using Microsoft.Extensions.Hosting;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace TEAMModelOS.SDK.DI
{
    public class BackgroundWorkerQueue
    {
        private readonly ConcurrentQueue<Func<CancellationToken, Task>> _workItems = new();
        private readonly SemaphoreSlim _signal = new(0);

        public async Task<Func<CancellationToken, Task>> DequeueAsync(CancellationToken cancellationToken)
        {
            await _signal.WaitAsync(cancellationToken);
            _workItems.TryDequeue(out var workItem);

            return workItem;
        }

        public void QueueBackgroundWorkItem(Func<CancellationToken, Task> workItem)
        {
            ArgumentNullException.ThrowIfNull(workItem);

            _workItems.Enqueue(workItem);
            _signal.Release();
        }
    }
    public class LongRunningService : BackgroundService
    {

        public LongRunningService(BackgroundWorkerQueue queue)
        {
            _queue = queue;
        }
        private readonly BackgroundWorkerQueue _queue;

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                var workItem = await _queue.DequeueAsync(stoppingToken);

                await workItem(stoppingToken);
            }
        }
    }
}