Implement Daybreak.API. Reorganize FocusView components (#995)

Daybreak.API/Models/AsyncRefreshCache.cs

@@ -0,0 +1,38 @@
+using System.Core.Extensions;
+using System.Extensions;
+
+namespace Daybreak.API.Models;
+
+public sealed class AsyncRefreshCache<T>(TimeSpan refreshRate, Func<CancellationToken, ValueTask<T>> refreshFunc)
+{
+    private readonly Func<CancellationToken, ValueTask<T>> refreshFunc = refreshFunc.ThrowIfNull();
+    
+    private readonly SemaphoreSlim semaphoreSlim = new(1);
+    
+    private T? cache;
+    private DateTime lastUpdateDateTime = DateTime.MinValue;
+    private TimeSpan refreshRate = refreshRate;
+
+    public async ValueTask<T> GetAsync(CancellationToken cancellationToken)
+    {
+        if (this.cache is not null && DateTime.UtcNow - this.lastUpdateDateTime < this.refreshRate)
+        {
+            return this.cache;
+        }
+
+        using var ctx = await this.semaphoreSlim.Acquire(cancellationToken);
+        if (DateTime.UtcNow - this.lastUpdateDateTime > this.refreshRate ||
+            this.cache is null)
+        {
+            this.lastUpdateDateTime = DateTime.UtcNow;
+            this.cache = await this.refreshFunc(cancellationToken);
+        }
+
+        return this.cache;
+    }
+
+    public void UpdateRefreshRate(TimeSpan newRefreshRate)
+    {
+        this.refreshRate = newRefreshRate;
+    }
+}