Added the guided chat to the BeyondFacts Lab (#1177)

app/MindWork AI Studio/Assistants/BeyondFactsLab/BeyondFactsLabStore.Threads.cs

@@ -0,0 +1,166 @@
+using System.Text.Json;
+
+using AIStudio.Chat;
+
+namespace AIStudio.Assistants.BeyondFactsLab;
+
+public sealed partial class BeyondFactsLabStore
+{
+    /// <summary>
+    /// The file of a step which holds its chat.
+    /// </summary>
+    private const string THREAD_FILE_NAME = "thread.json";
+
+    /// <summary>
+    /// Loads the chat of a step.
+    /// </summary>
+    /// <param name="location">The step of the preparation.</param>
+    /// <param name="token">The cancellation token.</param>
+    /// <returns>The chat, or null while the step has none.</returns>
+    /// <exception cref="InvalidDataException">This version cannot open the chat.</exception>
+    public async Task<ChatThread?> LoadThreadAsync(BflThreadLocation location, CancellationToken token = default)
+    {
+        await this.InitializeAsync(token);
+        return await this.LoadThreadWithoutInitializeAsync(location, token);
+    }
+
+    /// <summary>
+    /// Stores the chat of a step and counts it as a change of the preparation.
+    /// </summary>
+    /// <param name="location">The step of the preparation.</param>
+    /// <param name="thread">The chat.</param>
+    /// <param name="token">The cancellation token.</param>
+    /// <returns>The preparation with its new time of change.</returns>
+    /// <exception cref="FileNotFoundException">The preparation does not exist, e.g., because the person deleted it while the model answered.</exception>
+    /// <exception cref="InvalidDataException">This version cannot open the preparation or the stored chat, so it does not write them either.</exception>
+    public async Task<BflProject> SaveThreadAsync(BflThreadLocation location, ChatThread thread, CancellationToken token = default)
+    {
+        if (thread.ChatId != location.ChatId)
+            throw new ArgumentException("The chat belongs to another step.", nameof(thread));
+
+        await this.InitializeAsync(token);
+        var gate = this.GetLock(location.ProjectId);
+        await gate.WaitAsync(token);
+        try
+        {
+            var project = await this.LoadRequiredWithoutInitializeAsync(location.ProjectId, token);
+
+            // A chat which a newer version stored, or which is damaged, stays as it is:
+            await this.LoadThreadWithoutInitializeAsync(location, token);
+
+            await WriteTextAtomicAsync(this.ThreadPath(location), JsonSerializer.Serialize(thread, WorkspaceBehaviour.JSON_OPTIONS), token);
+
+            project.ModifiedAtUtc = DateTimeOffset.UtcNow;
+            await this.StoreProjectAsync(project, token);
+            return project;
+        }
+        finally
+        {
+            gate.Release();
+        }
+    }
+
+    /// <summary>
+    /// Deletes the chat of a step, so that its conversation starts over.
+    /// </summary>
+    /// <remarks>
+    /// Unlike the other files of a step, a chat which this version cannot open is deleted as well: the person asked
+    /// to start the conversation over, and nothing else refers to it.
+    /// </remarks>
+    /// <param name="location">The step of the preparation.</param>
+    /// <param name="token">The cancellation token.</param>
+    public async Task DeleteThreadAsync(BflThreadLocation location, CancellationToken token = default)
+    {
+        await this.InitializeAsync(token);
+        var gate = this.GetLock(location.ProjectId);
+        await gate.WaitAsync(token);
+        try
+        {
+            var path = this.ThreadPath(location);
+            if (File.Exists(path))
+                File.Delete(path);
+        }
+        finally
+        {
+            gate.Release();
+        }
+    }
+
+    /// <summary>
+    /// Finds the chats of every preparation on the disk, from the folders alone.
+    /// </summary>
+    /// <remarks>
+    /// For the cleanup of the provenance store at the start, which must know every chat which may refer to an entry,
+    /// also when the lab is switched off. A preparation this version cannot open keeps its chats as well.
+    /// </remarks>
+    /// <returns>The step of each chat, by the ID of the chat.</returns>
+    public IReadOnlyDictionary<Guid, BflThreadLocation> ReadAllThreadLocations()
+    {
+        var locations = new Dictionary<Guid, BflThreadLocation>();
+        if (!Directory.Exists(this.RootDirectory))
+            return locations;
+
+        foreach (var directory in Directory.EnumerateDirectories(this.RootDirectory))
+        {
+            if (!Guid.TryParse(Path.GetFileName(directory), out var projectId))
+                continue;
+
+            foreach (var step in BflStep.All)
+            {
+                var location = new BflThreadLocation(projectId, step);
+                if (File.Exists(this.ThreadPath(location)))
+                    locations[location.ChatId] = location;
+            }
+        }
+
+        return locations;
+    }
+
+    /// <summary>
+    /// Tells when the chat of a step was last written.
+    /// </summary>
+    /// <param name="location">The step of the preparation.</param>
+    /// <returns>The time, or null when the step has no chat.</returns>
+    public DateTimeOffset? GetThreadWrittenAt(BflThreadLocation location)
+    {
+        var path = this.ThreadPath(location);
+        return File.Exists(path) ? new DateTimeOffset(File.GetLastWriteTimeUtc(path)) : null;
+    }
+
+    /// <summary>
+    /// Reads the chat of a step without the first start of the store.
+    /// </summary>
+    /// <param name="location">The step of the preparation.</param>
+    /// <param name="token">The cancellation token.</param>
+    /// <returns>The chat, or null when there is no file.</returns>
+    /// <exception cref="InvalidDataException">This version cannot open the chat.</exception>
+    private async Task<ChatThread?> LoadThreadWithoutInitializeAsync(BflThreadLocation location, CancellationToken token)
+    {
+        var path = this.ThreadPath(location);
+        if (!File.Exists(path))
+            return null;
+
+        ChatThread? thread;
+        try
+        {
+            await using var stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read, 65_536, true);
+            thread = await JsonSerializer.DeserializeAsync<ChatThread>(stream, WorkspaceBehaviour.JSON_OPTIONS, token);
+        }
+        catch (Exception exception) when (exception is IOException or UnauthorizedAccessException or JsonException)
+        {
+            throw new InvalidDataException("This version of AI Studio cannot open the chat.", exception);
+        }
+
+        // A chat copied into another step would mix up what the provenance store keeps for it:
+        if (thread is null || thread.ChatId != location.ChatId || IsNull(thread.Blocks))
+            throw new InvalidDataException("This version of AI Studio cannot open the chat.");
+
+        return thread;
+    }
+
+    /// <summary>
+    /// Gets the file of the chat of a step.
+    /// </summary>
+    /// <param name="location">The step of the preparation.</param>
+    private string ThreadPath(BflThreadLocation location) => Path.Combine(this.ProjectDirectory(location.ProjectId), STEPS_DIRECTORY_NAME, location.Step.FolderName, THREAD_FILE_NAME);
+}