feat(services): implement VectorDbService for user-specific picture collections

Services/VectorDb/VectorDbService.cs

@@ -0,0 +1,79 @@
+using Foxel.Models.Vector;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.VectorData;
+using Microsoft.SemanticKernel.Connectors.InMemory;
+
+namespace Foxel.Services.VectorDB;
+
+public class VectorDbService
+{
+    private readonly VectorStore _vectorStore;
+    private readonly IDbContextFactory<MyDbContext> _contextFactory;
+
+    public VectorDbService(IDbContextFactory<MyDbContext> contextFactory)
+    {
+        _vectorStore = new InMemoryVectorStore();
+        _contextFactory = contextFactory;
+        _ = InitData();
+    }
+
+    private async Task InitData()
+    {
+        await using var dbContext = await _contextFactory.CreateDbContextAsync();
+        var userPictures = dbContext.Pictures
+            .Where(p => p.UserId != null && p.Embedding != null)
+            .Select(p => new { p.Id, p.Name, p.Embedding, p.UserId })
+            .GroupBy(p => p.UserId!.Value)
+            .ToList();
+
+        foreach (var group in userPictures)
+        {
+            int userId = group.Key;
+            var collectionName = $"picture_{userId}";
+            var collection = _vectorStore.GetCollection<int, PictureVector>(collectionName);
+            await collection.EnsureCollectionExistsAsync();
+
+            var picVectors = group.Select(p => new PictureVector
+            {
+                Id = p.Id,
+                Name = p.Name,
+                Embedding = p.Embedding
+            }).ToList();
+
+            foreach (var picVector in picVectors)
+            {
+                await collection.UpsertAsync(picVector);
+            }
+        }
+    }
+
+    public async Task<List<PictureVector>> SearchAsync(ReadOnlyMemory<float> query, int? userId, int topK = 10)
+    {
+        var collectionName = $"picture_{userId}";
+        var collection = _vectorStore.GetCollection<int, PictureVector>(collectionName);
+        var results = collection.SearchAsync(query, topK);
+        var res = new List<PictureVector>();
+        await foreach (var record in results)
+        {
+            res.Add(record.Record);
+        }
+
+        return res;
+    }
+
+    public async Task AddPictureToUserCollectionAsync(int userId, PictureVector pictureVector)
+    {
+        var collectionName = $"picture_{userId}";
+        var collection = _vectorStore.GetCollection<int, PictureVector>(collectionName);
+        await collection.EnsureCollectionExistsAsync();
+        await collection.UpsertAsync(pictureVector);
+    }
+
+    public async Task RemovePictureFromUserCollectionAsync(int userId, int pictureId)
+    {
+        var collectionName = $"picture_{userId}";
+        var collection = _vectorStore.GetCollection<int, PictureVector>(collectionName);
+        await collection.EnsureCollectionExistsAsync();
+        await collection.DeleteAsync(pictureId);
+    }
+}