Changes

api/Services/Rag/InMemoryCvVectorStore.cs

@@ -0,0 +1,79 @@
+using Api.Models.Rag;
+
+namespace Api.Services.Rag;
+
+public interface ICvVectorStore
+{
+    void Save(string documentId, IEnumerable<StoredCvChunk> chunks);
+    IReadOnlyList<StoredCvChunk> Get(string documentId);
+    IReadOnlyList<RetrievedCvChunk> Search(string documentId, float[] queryEmbedding, int topK);
+}
+
+public sealed class InMemoryCvVectorStore : ICvVectorStore
+{
+    private readonly object _lock = new();
+    private readonly Dictionary<string, List<StoredCvChunk>> _store = new(StringComparer.OrdinalIgnoreCase);
+
+    public void Save(string documentId, IEnumerable<StoredCvChunk> chunks)
+    {
+        lock (_lock)
+        {
+            CleanupExpiredUnsafe();
+            _store[documentId] = chunks.ToList();
+        }
+    }
+
+    public IReadOnlyList<StoredCvChunk> Get(string documentId)
+    {
+        lock (_lock)
+        {
+            CleanupExpiredUnsafe();
+            return _store.TryGetValue(documentId, out var chunks) ? chunks.ToList() : [];
+        }
+    }
+
+    public IReadOnlyList<RetrievedCvChunk> Search(string documentId, float[] queryEmbedding, int topK)
+    {
+        var chunks = Get(documentId);
+        if (chunks.Count == 0) return [];
+
+        return chunks
+            .Select(chunk => new RetrievedCvChunk
+            {
+                Text = chunk.Text,
+                ChunkIndex = chunk.ChunkIndex,
+                Score = CosineSimilarity(queryEmbedding, chunk.Embedding)
+            })
+            .OrderByDescending(x => x.Score)
+            .Take(Math.Clamp(topK, 1, 12))
+            .ToList();
+    }
+
+    private void CleanupExpiredUnsafe()
+    {
+        var now = DateTimeOffset.UtcNow;
+        foreach (var key in _store.Where(x => x.Value.All(c => c.ExpiresAt <= now)).Select(x => x.Key).ToList())
+        {
+            _store.Remove(key);
+        }
+    }
+
+    private static double CosineSimilarity(float[] a, float[] b)
+    {
+        if (a.Length != b.Length || a.Length == 0) return 0;
+
+        double dot = 0;
+        double magA = 0;
+        double magB = 0;
+
+        for (var i = 0; i < a.Length; i++)
+        {
+            dot += a[i] * b[i];
+            magA += a[i] * a[i];
+            magB += b[i] * b[i];
+        }
+
+        if (magA == 0 || magB == 0) return 0;
+        return dot / (Math.Sqrt(magA) * Math.Sqrt(magB));
+    }
+}