ilk commit

src/DownloadManager.Core/Queue/DownloadQueue.cs

@@ -0,0 +1,66 @@
+using DownloadManager.Core.Models;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace DownloadManager.Core.Queue;
+
+public class DownloadQueue
+{
+    private SemaphoreSlim _concurrencySemaphore;
+    private readonly SemaphoreSlim _itemsAvailableSemaphore = new(0);
+    private readonly PriorityQueue<DownloadItem, int> _inner = new();
+    private readonly object _lock = new();
+
+    public DownloadQueue(int maxConcurrent = 3)
+        => _concurrencySemaphore = new SemaphoreSlim(maxConcurrent, maxConcurrent);
+
+    public void Enqueue(DownloadItem item)
+    {
+        lock (_lock)
+        {
+            _inner.Enqueue(item, item.Priority);
+            _itemsAvailableSemaphore.Release();
+        }
+    }
+
+    public async Task<DownloadItem?> DequeueAsync(CancellationToken ct)
+    {
+        // Önce bir slotun boşalmasını bekle (concurrency limit)
+        await _concurrencySemaphore.WaitAsync(ct);
+
+        try
+        {
+            // Sonra kuyrukta bir öğe olmasını bekle
+            await _itemsAvailableSemaphore.WaitAsync(ct);
+
+            lock (_lock)
+            {
+                if (_inner.TryDequeue(out var item, out _))
+                    return item;
+            }
+        }
+        catch
+        {
+            _concurrencySemaphore.Release();
+            throw;
+        }
+        
+        return null;
+    }
+
+    public void Release() => _concurrencySemaphore.Release();
+
+    /// <summary>Çalışma zamanında limit değiştir (ayarlar panelinden)</summary>
+    public void SetConcurrencyLimit(int newLimit)
+    {
+        lock (_lock)
+        {
+            // Not: Bu basit uygulama çalışma anındaki limit değişimini tam olarak yansıtmayabilir, 
+            // ama temel yapı için yeterli.
+            var old = _concurrencySemaphore;
+            _concurrencySemaphore = new SemaphoreSlim(newLimit, newLimit);
+            old.Dispose();
+        }
+    }
+}