Add resilient Azure offline transcription backlog

MeetingAssistant/Recording/FileOfflineTranscriptionBacklog.cs

@@ -0,0 +1,134 @@
+using System.Text.Json;
+using Microsoft.Extensions.Options;
+
+namespace MeetingAssistant.Recording;
+
+public sealed class FileOfflineTranscriptionBacklog : IOfflineTranscriptionBacklog
+{
+    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web)
+    {
+        WriteIndented = true
+    };
+
+    private readonly MeetingAssistantOptions options;
+    private readonly ILogger<FileOfflineTranscriptionBacklog> logger;
+
+    public FileOfflineTranscriptionBacklog(
+        IOptions<MeetingAssistantOptions> options,
+        ILogger<FileOfflineTranscriptionBacklog> logger)
+    {
+        this.options = options.Value;
+        this.logger = logger;
+    }
+
+    public async Task EnqueueAsync(OfflineTranscriptionBacklogItem item, CancellationToken cancellationToken)
+    {
+        var folder = GetBacklogFolder(options);
+        Directory.CreateDirectory(folder);
+        var path = GetItemPath(folder, item.Id);
+        await File.WriteAllTextAsync(path, JsonSerializer.Serialize(item, JsonOptions), cancellationToken);
+        logger.LogInformation(
+            "Queued offline transcription backlog item {BacklogItemId} for recording {RecordingPath}",
+            item.Id,
+            item.AudioPath);
+    }
+
+    public async Task<IReadOnlyList<OfflineTranscriptionBacklogItem>> ListAsync(CancellationToken cancellationToken)
+    {
+        var folder = GetBacklogFolder(options);
+        if (!Directory.Exists(folder))
+        {
+            return [];
+        }
+
+        var items = new List<OfflineTranscriptionBacklogItem>();
+        foreach (var path in Directory.EnumerateFiles(folder, "*.json", SearchOption.TopDirectoryOnly))
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+            try
+            {
+                var content = await File.ReadAllTextAsync(path, cancellationToken);
+                if (JsonSerializer.Deserialize<OfflineTranscriptionBacklogItem>(content, JsonOptions) is { } item)
+                {
+                    items.Add(item);
+                }
+            }
+            catch (JsonException exception)
+            {
+                logger.LogWarning(exception, "Could not read offline transcription backlog item {BacklogItemPath}", path);
+            }
+            catch (IOException exception)
+            {
+                logger.LogWarning(exception, "Could not read offline transcription backlog item {BacklogItemPath}", path);
+            }
+        }
+
+        return items;
+    }
+
+    public async Task CompleteAsync(string id, CancellationToken cancellationToken)
+    {
+        var folder = GetBacklogFolder(options);
+        var path = GetItemPath(folder, id);
+        if (!File.Exists(path))
+        {
+            return;
+        }
+
+        OfflineTranscriptionBacklogItem? item = null;
+        try
+        {
+            item = JsonSerializer.Deserialize<OfflineTranscriptionBacklogItem>(
+                await File.ReadAllTextAsync(path, cancellationToken),
+                JsonOptions);
+        }
+        catch (JsonException exception)
+        {
+            logger.LogWarning(exception, "Could not read completed offline transcription backlog item {BacklogItemPath}", path);
+        }
+
+        File.Delete(path);
+        if (item is not null && File.Exists(item.AudioPath))
+        {
+            DeleteCompletedAudio(item.AudioPath);
+        }
+    }
+
+    private static string GetBacklogFolder(MeetingAssistantOptions options)
+    {
+        return Path.Combine(VaultPath.Resolve(options.Recording.TemporaryRecordingsFolder), "offline-transcription-backlog");
+    }
+
+    private static string GetItemPath(string folder, string id)
+    {
+        return Path.Combine(folder, $"{id}.json");
+    }
+
+    private void DeleteCompletedAudio(string audioPath)
+    {
+        try
+        {
+            File.Delete(audioPath);
+        }
+        catch (FileNotFoundException)
+        {
+        }
+        catch (DirectoryNotFoundException)
+        {
+        }
+        catch (IOException exception)
+        {
+            logger.LogWarning(
+                exception,
+                "Could not delete completed offline transcription recording file {RecordingPath}",
+                audioPath);
+        }
+        catch (UnauthorizedAccessException exception)
+        {
+            logger.LogWarning(
+                exception,
+                "Could not delete completed offline transcription recording file {RecordingPath}",
+                audioPath);
+        }
+    }
+}