added manual refresh and cleaned up code

app/MindWork AI Studio/Tools/Services/DataSourceEmbeddingService.State.cs

@@ -0,0 +1,89 @@
+using System.Text.Json;
+
+using AIStudio.Settings;
+
+namespace AIStudio.Tools.Services;
+
+public sealed partial class DataSourceEmbeddingService
+{
+    private const string STATE_FILENAME = "rag-embedding-state.json";
+
+    private readonly JsonSerializerOptions jsonOptions = new()
+    {
+        WriteIndented = true,
+    };
+
+    private async Task EnsureStateLoadedAsync(CancellationToken token)
+    {
+        if (this.stateLoaded)
+            return;
+
+        await this.stateLock.WaitAsync(token);
+        try
+        {
+            if (this.stateLoaded)
+                return;
+
+            var statePath = this.GetStatePath();
+            if (!string.IsNullOrWhiteSpace(statePath) && File.Exists(statePath))
+            {
+                var json = await File.ReadAllTextAsync(statePath, token);
+                var persistedState = JsonSerializer.Deserialize<PersistedEmbeddingState>(json, this.jsonOptions);
+                this.manifests = persistedState?.DataSources ?? new Dictionary<string, DataSourceEmbeddingManifest>(StringComparer.OrdinalIgnoreCase);
+            }
+
+            this.stateLoaded = true;
+        }
+        finally
+        {
+            this.stateLock.Release();
+        }
+    }
+
+    private async Task<DataSourceEmbeddingManifest> GetManifestAsync(string dataSourceId, CancellationToken token)
+    {
+        await this.EnsureStateLoadedAsync(token);
+        if (this.manifests.TryGetValue(dataSourceId, out var manifest))
+            return manifest;
+
+        manifest = new DataSourceEmbeddingManifest();
+        this.manifests[dataSourceId] = manifest;
+        return manifest;
+    }
+
+    private async Task SaveStateAsync(CancellationToken token)
+    {
+        var statePath = this.GetStatePath();
+        if (string.IsNullOrWhiteSpace(statePath))
+            return;
+
+        var directory = Path.GetDirectoryName(statePath);
+        if (!string.IsNullOrWhiteSpace(directory))
+            Directory.CreateDirectory(directory);
+
+        var persistedState = new PersistedEmbeddingState
+        {
+            DataSources = this.manifests
+        };
+
+        var json = JsonSerializer.Serialize(persistedState, this.jsonOptions);
+        await File.WriteAllTextAsync(statePath, json, token);
+    }
+
+    private async Task ResetPersistedStateAsync(string dataSourceId)
+    {
+        await this.EnsureStateLoadedAsync(CancellationToken.None);
+        this.manifests.Remove(dataSourceId);
+        await this.DeleteCollectionAsync(this.GetCollectionName(dataSourceId));
+        await this.SaveStateAsync(CancellationToken.None);
+        this.logger.LogInformation("Reset persisted embedding state for data source '{DataSourceId}'.", dataSourceId);
+    }
+
+    private string GetStatePath()
+    {
+        if (string.IsNullOrWhiteSpace(SettingsManager.ConfigDirectory))
+            return string.Empty;
+
+        return Path.Combine(SettingsManager.ConfigDirectory, STATE_FILENAME);
+    }
+}