Added the Model Comparison assistant for blind comparisons of two models (#1009)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Assistants/ModelComparison/ModelComparisonStore.Results.cs

@@ -0,0 +1,105 @@
+using System.Runtime.CompilerServices;
+
+namespace AIStudio.Assistants.ModelComparison;
+
+public sealed partial class ModelComparisonStore
+{
+    /// <summary>
+    /// The folder of the stored comparisons, one file per batch.
+    /// </summary>
+    private const string RESULTS_DIRECTORY_NAME = "results";
+
+    /// <summary>
+    /// Gets the folder of the stored comparisons.
+    /// </summary>
+    private string ResultsDirectory => Path.Combine(this.RootDirectory, RESULTS_DIRECTORY_NAME);
+
+    /// <summary>
+    /// Gets the file of a stored comparison.
+    /// </summary>
+    /// <param name="recordId">The ID of the batch.</param>
+    private string ResultPath(Guid recordId) => Path.Combine(this.ResultsDirectory, $"{recordId:D}.json");
+
+    /// <summary>
+    /// Stores what the assistant keeps of a batch, in place of what it kept of the same batch before.
+    /// </summary>
+    /// <param name="record">The stored comparison.</param>
+    /// <param name="token">The cancellation token.</param>
+    /// <exception cref="ArgumentException">The stored comparison has no ID.</exception>
+    public async Task SaveResultAsync(ModelComparisonRecord record, CancellationToken token = default)
+    {
+        if (record.Id == Guid.Empty)
+            throw new ArgumentException("A stored comparison needs an ID.", nameof(record));
+
+        await this.InitializeAsync(token);
+        var gate = this.GetLock(record.Id);
+        await gate.WaitAsync(token);
+        try
+        {
+            await WriteJsonAtomicAsync(this.ResultPath(record.Id), record, token);
+        }
+        finally
+        {
+            gate.Release();
+        }
+    }
+
+    /// <summary>
+    /// Reads the stored comparisons one by one, so that never more than one of them is in memory at once.
+    /// </summary>
+    /// <remarks>
+    /// A file this version cannot read is skipped, but stays on the disk, see ModelComparisonJson.
+    /// </remarks>
+    /// <param name="token">The cancellation token.</param>
+    /// <returns>The stored comparisons, in no particular order.</returns>
+    public async IAsyncEnumerable<ModelComparisonRecord> ReadResultsAsync([EnumeratorCancellation] CancellationToken token = default)
+    {
+        await this.InitializeAsync(token);
+        if (!Directory.Exists(this.ResultsDirectory))
+            yield break;
+
+        foreach (var path in Directory.EnumerateFiles(this.ResultsDirectory, "*.json"))
+        {
+            token.ThrowIfCancellationRequested();
+            if (!Guid.TryParseExact(Path.GetFileNameWithoutExtension(path), "D", out var recordId))
+                continue;
+
+            // The ID inside the file must not lead to another file than the one it was read from:
+            if (await this.ReadJsonAsync<ModelComparisonRecord>(path, token) is { } record)
+                yield return record with { Id = recordId };
+        }
+    }
+
+    /// <summary>
+    /// Deletes all stored comparisons, the presets aside.
+    /// </summary>
+    /// <remarks>
+    /// Unlike reading, deleting takes the files this version cannot read along: the user asked for all results to go.
+    /// </remarks>
+    /// <param name="token">The cancellation token.</param>
+    public async Task DeleteAllResultsAsync(CancellationToken token = default)
+    {
+        await this.InitializeAsync(token);
+        if (!Directory.Exists(this.ResultsDirectory))
+            return;
+
+        foreach (var path in Directory.EnumerateFiles(this.ResultsDirectory, "*.json").ToList())
+        {
+            token.ThrowIfCancellationRequested();
+            if (!Guid.TryParseExact(Path.GetFileNameWithoutExtension(path), "D", out var recordId))
+                continue;
+
+            var gate = this.GetLock(recordId);
+            await gate.WaitAsync(token);
+            try
+            {
+                File.Delete(path);
+            }
+            finally
+            {
+                gate.Release();
+                this.ForgetLock(recordId);
+            }
+        }
+    }
+}