up

src/Signals/StellaOps.Signals/Persistence/IReachabilityFactRepository.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 using StellaOps.Signals.Models;
@@ -9,4 +11,24 @@ public interface IReachabilityFactRepository
     Task<ReachabilityFactDocument> UpsertAsync(ReachabilityFactDocument document, CancellationToken cancellationToken);
 
     Task<ReachabilityFactDocument?> GetBySubjectAsync(string subjectKey, CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Gets documents with ComputedAt older than the specified cutoff.
+    /// </summary>
+    Task<IReadOnlyList<ReachabilityFactDocument>> GetExpiredAsync(DateTimeOffset cutoff, int limit, CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Deletes the document with the specified subject key.
+    /// </summary>
+    Task<bool> DeleteAsync(string subjectKey, CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Gets the count of runtime facts for a subject.
+    /// </summary>
+    Task<int> GetRuntimeFactsCountAsync(string subjectKey, CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Trims runtime facts for a subject to the specified limit, keeping most recent.
+    /// </summary>
+    Task TrimRuntimeFactsAsync(string subjectKey, int maxCount, CancellationToken cancellationToken);
 }

src/Signals/StellaOps.Signals/Persistence/InMemoryReachabilityFactRepository.cs

@@ -1,4 +1,7 @@
+using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using StellaOps.Signals.Models;
@@ -31,6 +34,66 @@ internal sealed class InMemoryReachabilityFactRepository : IReachabilityFactRepo
         return Task.FromResult(_store.TryGetValue(subjectKey, out var doc) ? Clone(doc) : null);
     }
 
+    public Task<IReadOnlyList<ReachabilityFactDocument>> GetExpiredAsync(DateTimeOffset cutoff, int limit, CancellationToken cancellationToken)
+    {
+        var expired = _store.Values
+            .Where(d => d.ComputedAt < cutoff)
+            .OrderBy(d => d.ComputedAt)
+            .Take(limit)
+            .Select(Clone)
+            .ToList();
+
+        return Task.FromResult<IReadOnlyList<ReachabilityFactDocument>>(expired);
+    }
+
+    public Task<bool> DeleteAsync(string subjectKey, CancellationToken cancellationToken)
+    {
+        if (string.IsNullOrWhiteSpace(subjectKey))
+        {
+            throw new ArgumentException("Subject key is required.", nameof(subjectKey));
+        }
+
+        return Task.FromResult(_store.TryRemove(subjectKey, out _));
+    }
+
+    public Task<int> GetRuntimeFactsCountAsync(string subjectKey, CancellationToken cancellationToken)
+    {
+        if (string.IsNullOrWhiteSpace(subjectKey))
+        {
+            throw new ArgumentException("Subject key is required.", nameof(subjectKey));
+        }
+
+        if (_store.TryGetValue(subjectKey, out var doc))
+        {
+            return Task.FromResult(doc.RuntimeFacts?.Count ?? 0);
+        }
+
+        return Task.FromResult(0);
+    }
+
+    public Task TrimRuntimeFactsAsync(string subjectKey, int maxCount, CancellationToken cancellationToken)
+    {
+        if (string.IsNullOrWhiteSpace(subjectKey))
+        {
+            throw new ArgumentException("Subject key is required.", nameof(subjectKey));
+        }
+
+        if (_store.TryGetValue(subjectKey, out var doc) && doc.RuntimeFacts is { Count: > 0 })
+        {
+            if (doc.RuntimeFacts.Count > maxCount)
+            {
+                var trimmed = doc.RuntimeFacts
+                    .OrderByDescending(f => f.ObservedAt ?? DateTimeOffset.MinValue)
+                    .ThenByDescending(f => f.HitCount)
+                    .Take(maxCount)
+                    .ToList();
+                doc.RuntimeFacts = trimmed;
+            }
+        }
+
+        return Task.CompletedTask;
+    }
+
     private static ReachabilityFactDocument Clone(ReachabilityFactDocument source) => new()
     {
         Id = source.Id,