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Jellyfin.Plugin.JRay/Services/TruthDataService.cs

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+using System;
+using System.Collections.Concurrent;
+using System.IO;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Jellyfin.Plugin.JRay.Models;
+using Jellyfin.Plugin.JRay.Services.Interfaces;
+using MediaBrowser.Controller.Library;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Plugin.JRay.Services;
+
+/// <summary>
+/// Loads scene-actor-extraction truth files from disk, alongside each media
+/// item's source file, and caches the parsed result for a configurable
+/// duration.
+/// </summary>
+public sealed class TruthDataService : ITruthDataService
+{
+    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web);
+
+    private readonly ILibraryManager _libraryManager;
+    private readonly IManagedTruthStore _managedTruthStore;
+    private readonly ILogger<TruthDataService> _logger;
+    private readonly ConcurrentDictionary<Guid, CacheEntry> _cache = new();
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TruthDataService"/> class.
+    /// </summary>
+    /// <param name="libraryManager">The Jellyfin library manager.</param>
+    /// <param name="managedTruthStore">The managed truth store.</param>
+    /// <param name="logger">The logger.</param>
+    public TruthDataService(ILibraryManager libraryManager, IManagedTruthStore managedTruthStore, ILogger<TruthDataService> logger)
+    {
+        _libraryManager = libraryManager;
+        _managedTruthStore = managedTruthStore;
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+    public async Task<TruthFile?> GetTruthAsync(Guid itemId, CancellationToken cancellationToken)
+    {
+        var cacheDuration = TimeSpan.FromMinutes(Math.Max(0, Plugin.Instance?.Configuration.CacheDurationMinutes ?? 0));
+
+        if (_cache.TryGetValue(itemId, out var cached) && DateTime.UtcNow - cached.LoadedAt < cacheDuration)
+        {
+            return cached.Truth;
+        }
+
+        var managed = await _managedTruthStore.LoadAsync(itemId, cancellationToken).ConfigureAwait(false);
+        if (managed is not null)
+        {
+            _cache[itemId] = new CacheEntry(managed, DateTime.UtcNow);
+            return managed;
+        }
+
+        var item = _libraryManager.GetItemById(itemId);
+        if (item is null || string.IsNullOrEmpty(item.Path))
+        {
+            _logger.LogDebug("JRay: item {ItemId} not found or has no path", itemId);
+            return null;
+        }
+
+        var suffix = Plugin.Instance?.Configuration.TruthFileSuffix ?? ".jray.json";
+        var truthPath = Path.Combine(
+            Path.GetDirectoryName(item.Path) ?? string.Empty,
+            Path.GetFileNameWithoutExtension(item.Path) + suffix);
+
+        if (!File.Exists(truthPath))
+        {
+            _logger.LogDebug("JRay: no truth file at {TruthPath}", truthPath);
+            _cache[itemId] = new CacheEntry(null, DateTime.UtcNow);
+            return null;
+        }
+
+        try
+        {
+            using var stream = File.OpenRead(truthPath);
+            var truth = await JsonSerializer.DeserializeAsync<TruthFile>(stream, JsonOptions, cancellationToken)
+                .ConfigureAwait(false);
+            _cache[itemId] = new CacheEntry(truth, DateTime.UtcNow);
+            return truth;
+        }
+        catch (Exception ex) when (ex is IOException or JsonException)
+        {
+            _logger.LogWarning(ex, "JRay: failed to read truth file {TruthPath}", truthPath);
+            return null;
+        }
+    }
+
+    /// <inheritdoc />
+    public void Invalidate(Guid itemId)
+    {
+        _cache.TryRemove(itemId, out _);
+    }
+
+    private sealed record CacheEntry(TruthFile? Truth, DateTime LoadedAt);
+}