added retrieval with vector and bm25 search

app/MindWork AI Studio/Tools/Services/DataSourceLocalRetrievalService.cs

@@ -0,0 +1,307 @@
+using AIStudio.Chat;
+using AIStudio.Provider;
+using AIStudio.Settings;
+using AIStudio.Settings.DataModel;
+using AIStudio.Tools.Databases;
+using AIStudio.Tools.Databases.EmbeddingState;
+using AIStudio.Tools.Databases.VectorStore;
+using AIStudio.Tools.RAG;
+
+namespace AIStudio.Tools.Services;
+
+public sealed class DataSourceLocalRetrievalService(
+    SettingsManager settingsManager,
+    DatabaseClientProvider databaseClientProvider,
+    ILogger<DataSourceLocalRetrievalService> logger)
+{
+    private enum RetrievalChannel
+    {
+        VECTOR,
+        BM25,
+    }
+
+    private sealed record LocalRetrievalHit(
+        RetrievalChannel Channel,
+        string ChunkId,
+        string ParentFileId,
+        string DataSourceId,
+        string DataSourceName,
+        string DataSourceType,
+        string AbsolutePath,
+        string FileName,
+        string RelativePath,
+        string FileType,
+        int? PageNumber,
+        int ChunkIndex,
+        string Text,
+        double Score,
+        int Rank,
+        string ComplianceLevel,
+        int ComplianceLevelRank);
+
+    public Task<IReadOnlyList<IRetrievalContext>> RetrieveDataAsync(DataSourceLocalFile dataSource, IContent lastUserPrompt, ChatThread thread, CancellationToken token = default) =>
+        this.RetrieveDataAsync((IInternalDataSource)dataSource, lastUserPrompt, token);
+
+    public Task<IReadOnlyList<IRetrievalContext>> RetrieveDataAsync(DataSourceLocalDirectory dataSource, IContent lastUserPrompt, ChatThread thread, CancellationToken token = default) =>
+        this.RetrieveDataAsync((IInternalDataSource)dataSource, lastUserPrompt, token);
+
+    private async Task<IReadOnlyList<IRetrievalContext>> RetrieveDataAsync(IInternalDataSource dataSource, IContent lastUserPrompt, CancellationToken token)
+    {
+        var query = GetQueryText(lastUserPrompt);
+        if (string.IsNullOrWhiteSpace(query))
+        {
+            logger.LogDebug("Skipping local retrieval for data source '{DataSourceName}' ({DataSourceId}) because the latest prompt does not contain text.", dataSource.Name, dataSource.Id);
+            return [];
+        }
+
+        var maxMatches = (int)dataSource.MaxMatches;
+        if (maxMatches == 0)
+            return [];
+
+        var candidateLimit = maxMatches * 2;
+        var collectionName = DataSourceEmbeddingNames.GetCollectionName(dataSource.Name, dataSource.Id);
+        var vectorTask = this.SearchVectorAsync(dataSource, query, candidateLimit, collectionName, token);
+        var bm25Task = this.SearchBm25Async(dataSource, query, candidateLimit, token);
+
+        await Task.WhenAll(vectorTask, bm25Task);
+        token.ThrowIfCancellationRequested();
+
+        var hits = MergeResults(vectorTask.Result, bm25Task.Result, maxMatches);
+        logger.LogInformation(
+            "Retrieved {MergedHits} local RAG hits for data source '{DataSourceName}' ({DataSourceId}). VectorCandidates={VectorHits}, BM25Candidates={BM25Hits}, RequestedPerChannel={RequestedPerChannel}.",
+            hits.Count,
+            dataSource.Name,
+            dataSource.Id,
+            vectorTask.Result.Count,
+            bm25Task.Result.Count,
+            maxMatches);
+
+        return hits
+            .Where(hit => !string.IsNullOrWhiteSpace(hit.Text))
+            .Select(ToRetrievalContext)
+            .ToList();
+    }
+
+    private async Task<IReadOnlyList<VectorSearchResult>> SearchVectorAsync(
+        IInternalDataSource dataSource,
+        string query,
+        int maxMatches,
+        string collectionName,
+        CancellationToken token)
+    {
+        try
+        {
+            var vectorStore = await databaseClientProvider.GetVectorStoreAsync(token);
+            if (!vectorStore.IsAvailable)
+            {
+                logger.LogWarning(
+                    "Skipping vector retrieval for data source '{DataSourceName}' ({DataSourceId}) because vector store '{VectorStoreName}' is unavailable.",
+                    dataSource.Name,
+                    dataSource.Id,
+                    vectorStore.Name);
+                return [];
+            }
+
+            if (!DataSourceEmbeddingProviders.TryResolve(settingsManager, dataSource, out var embeddingProvider))
+            {
+                logger.LogWarning("Skipping vector retrieval for data source '{DataSourceName}' ({DataSourceId}) because the selected embedding provider is not available.", dataSource.Name, dataSource.Id);
+                return [];
+            }
+
+            var provider = embeddingProvider.CreateProvider();
+            var vectors = await provider.EmbedTextAsync(embeddingProvider.Model, settingsManager, token, [query]);
+            token.ThrowIfCancellationRequested();
+            var vector = vectors.FirstOrDefault();
+            if (vector is null || vector.Count == 0)
+            {
+                logger.LogWarning("Skipping vector retrieval for data source '{DataSourceName}' ({DataSourceId}) because query embedding returned no vector.", dataSource.Name, dataSource.Id);
+                return [];
+            }
+
+            return await vectorStore.SearchEmbeddingAsync(collectionName, vector, maxMatches, token);
+        }
+        catch (OperationCanceledException) when (token.IsCancellationRequested)
+        {
+            throw;
+        }
+        catch (Exception exception)
+        {
+            logger.LogWarning(exception, "Vector retrieval failed for data source '{DataSourceName}' ({DataSourceId}).", dataSource.Name, dataSource.Id);
+            return [];
+        }
+    }
+
+    private async Task<IReadOnlyList<EmbeddingStateSearchResult>> SearchBm25Async(IInternalDataSource dataSource, string query, int maxMatches, CancellationToken token)
+    {
+        try
+        {
+            var embeddingState = await databaseClientProvider.GetEmbeddingStateAsync(token);
+            if (!embeddingState.IsAvailable)
+            {
+                logger.LogWarning(
+                    "Skipping BM25 retrieval for data source '{DataSourceName}' ({DataSourceId}) because local RAG index '{DatabaseName}' is unavailable.",
+                    dataSource.Name,
+                    dataSource.Id,
+                    embeddingState.Name);
+                return [];
+            }
+
+            return await embeddingState.SearchChunksAsync(dataSource.Id, query, maxMatches, token);
+        }
+        catch (OperationCanceledException) when (token.IsCancellationRequested)
+        {
+            throw;
+        }
+        catch (Exception exception)
+        {
+            logger.LogWarning(exception, "BM25 retrieval failed for data source '{DataSourceName}' ({DataSourceId}).", dataSource.Name, dataSource.Id);
+            return [];
+        }
+    }
+
+    private static IReadOnlyList<LocalRetrievalHit> MergeResults(
+        IReadOnlyList<VectorSearchResult> vectorResults,
+        IReadOnlyList<EmbeddingStateSearchResult> bm25Results,
+        int maxMatches)
+    {
+        // Future reranking should replace this deterministic channel merge.
+        var merged = new List<LocalRetrievalHit>(maxMatches * 2);
+        var seenChunkIds = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        AppendHits(
+            merged,
+            seenChunkIds,
+            vectorResults
+                .Select((result, index) => FromVectorResult(result, index + 1)),
+            maxMatches);
+
+        AppendHits(
+            merged,
+            seenChunkIds,
+            bm25Results
+                .Select((result, index) => FromBm25Result(result, index + 1)),
+            maxMatches);
+
+        return merged;
+    }
+
+    private static void AppendHits(List<LocalRetrievalHit> merged, HashSet<string> seenChunkIds, IEnumerable<LocalRetrievalHit> hits, int maxNewHits)
+    {
+        var added = 0;
+        foreach (var hit in hits)
+        {
+            if (!string.IsNullOrWhiteSpace(hit.ChunkId) && !seenChunkIds.Add(hit.ChunkId))
+                continue;
+
+            merged.Add(hit);
+            added++;
+            if (added >= maxNewHits)
+                return;
+        }
+    }
+
+    private static LocalRetrievalHit FromVectorResult(VectorSearchResult result, int rank) =>
+        new(
+            RetrievalChannel.VECTOR,
+            result.ChunkId,
+            result.ParentFileId,
+            result.DataSourceId,
+            result.DataSourceName,
+            result.DataSourceType,
+            FirstNonEmpty(result.AbsolutePath, result.FilePath),
+            result.FileName,
+            result.RelativePath,
+            result.FileType,
+            result.PageNumber,
+            result.ChunkIndex,
+            result.Text,
+            result.Score,
+            rank,
+            result.ComplianceLevel,
+            result.ComplianceLevelRank);
+
+    private static LocalRetrievalHit FromBm25Result(EmbeddingStateSearchResult result, int rank) =>
+        new(
+            RetrievalChannel.BM25,
+            result.ChunkId,
+            result.ParentFileId,
+            result.DataSourceId,
+            result.DataSourceName,
+            result.DataSourceType,
+            result.AbsolutePath,
+            result.FileName,
+            result.RelativePath,
+            result.FileType,
+            result.PageNumber,
+            result.ChunkIndex,
+            result.ChunkText,
+            result.Score,
+            rank,
+            result.ComplianceLevel,
+            result.ComplianceLevelRank);
+
+    private static RetrievalTextContext ToRetrievalContext(LocalRetrievalHit hit)
+    {
+        var sourceName = FirstNonEmpty(hit.FileName, hit.DataSourceName);
+        var path = FirstNonEmpty(hit.AbsolutePath, hit.RelativePath);
+        var referenceLink = string.IsNullOrWhiteSpace(path) ? string.Empty : BuildReferenceLink(path, hit);
+
+        return new RetrievalTextContext
+        {
+            DataSourceName = sourceName,
+            Category = RetrievalContentCategory.TEXT,
+            Type = GetRetrievalContentType(hit.FileType),
+            Path = path,
+            Links = [],
+            MatchedText = hit.Text,
+            SurroundingContent = [],
+            ReferenceTitle = BuildReferenceTitle(hit),
+            ReferenceLink = referenceLink,
+        };
+    }
+
+    private static string BuildReferenceTitle(LocalRetrievalHit hit)
+    {
+        var sourceName = FirstNonEmpty(hit.FileName, hit.DataSourceName);
+        var page = hit.PageNumber is > 0 ? $", page {hit.PageNumber}" : string.Empty;
+        return $"{sourceName} (chunk {hit.ChunkIndex + 1}{page})";
+    }
+
+    private static string BuildReferenceLink(string path, LocalRetrievalHit hit)
+    {
+        var link = NormalizeLocalReferencePath(path);
+        var separator = link.Contains('#', StringComparison.Ordinal) ? "&" : "#";
+        return $"{link}{separator}chunk={hit.ChunkIndex}";
+    }
+
+    private static string NormalizeLocalReferencePath(string path)
+    {
+        try
+        {
+            return Path.IsPathRooted(path)
+                ? new Uri(Path.GetFullPath(path)).AbsoluteUri
+                : path;
+        }
+        catch
+        {
+            return path;
+        }
+    }
+
+    private static RetrievalContentType GetRetrievalContentType(string fileType) => fileType.TrimStart('.').ToLowerInvariant() switch
+    {
+        "csv" or "tsv" or "ods" or "xls" or "xlsx" or "xlsm" or "xlsb" => RetrievalContentType.TEXT_SPREADSHEET,
+        "odp" or "ppt" or "pptx" => RetrievalContentType.TEXT_PRESENTATION,
+        "htm" or "html" => RetrievalContentType.TEXT_WEBSITE,
+        _ => RetrievalContentType.TEXT_DOCUMENT
+    };
+
+    private static string GetQueryText(IContent lastUserPrompt) => lastUserPrompt switch
+    {
+        ContentText text => text.Text,
+        _ => string.Empty
+    };
+
+    private static string FirstNonEmpty(params string[] values) =>
+        values.FirstOrDefault(value => !string.IsNullOrWhiteSpace(value)) ?? string.Empty;
+}