Backport pull request #8087 from jellyfin/release-10.8.z

feat: make subtitleeditparser generic

Authored-by: Claus Vium <cvium@users.noreply.github.com>

Merged-by: Bond-009 <bond.009@outlook.com>

Original-merge: 7323ccfc23

MediaBrowser.MediaEncoding/Subtitles/SubtitleEditParser.cs

@@ -1,12 +1,14 @@
+using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
 using System.Linq;
-using System.Threading;
+using System.Reflection;
 using Jellyfin.Extensions;
 using MediaBrowser.Model.MediaInfo;
 using Microsoft.Extensions.Logging;
 using Nikse.SubtitleEdit.Core.Common;
-using ILogger = Microsoft.Extensions.Logging.ILogger;
+using Nikse.SubtitleEdit.Core.SubtitleFormats;
 using SubtitleFormat = Nikse.SubtitleEdit.Core.SubtitleFormats.SubtitleFormat;
 
 namespace MediaBrowser.MediaEncoding.Subtitles
@@ -14,31 +16,57 @@ namespace MediaBrowser.MediaEncoding.Subtitles
     /// <summary>
     /// SubStation Alpha subtitle parser.
     /// </summary>
-    /// <typeparam name="T">The <see cref="SubtitleFormat" />.</typeparam>
-    public abstract class SubtitleEditParser<T> : ISubtitleParser
-        where T : SubtitleFormat, new()
+    public class SubtitleEditParser : ISubtitleParser
     {
-        private readonly ILogger _logger;
+        private readonly ILogger<SubtitleEditParser> _logger;
+        private readonly Dictionary<string, SubtitleFormat[]> _subtitleFormats;
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="SubtitleEditParser{T}"/> class.
+        /// Initializes a new instance of the <see cref="SubtitleEditParser"/> class.
         /// </summary>
         /// <param name="logger">The logger.</param>
-        protected SubtitleEditParser(ILogger logger)
+        public SubtitleEditParser(ILogger<SubtitleEditParser> logger)
         {
             _logger = logger;
+            _subtitleFormats = GetSubtitleFormats()
+                .Where(subtitleFormat => !string.IsNullOrEmpty(subtitleFormat.Extension))
+                .GroupBy(subtitleFormat => subtitleFormat.Extension.TrimStart('.'), StringComparer.OrdinalIgnoreCase)
+                .ToDictionary(g => g.Key, g => g.ToArray(), StringComparer.OrdinalIgnoreCase);
         }
 
         /// <inheritdoc />
-        public SubtitleTrackInfo Parse(Stream stream, CancellationToken cancellationToken)
+        public SubtitleTrackInfo Parse(Stream stream, string fileExtension)
         {
             var subtitle = new Subtitle();
-            var subRip = new T();
             var lines = stream.ReadAllLines().ToList();
-            subRip.LoadSubtitle(subtitle, lines, "untitled");
-            if (subRip.ErrorCount > 0)
+
+            if (!_subtitleFormats.TryGetValue(fileExtension, out var subtitleFormats))
             {
-                _logger.LogError("{ErrorCount} errors encountered while parsing subtitle", subRip.ErrorCount);
+                throw new ArgumentException($"Unsupported file extension: {fileExtension}", nameof(fileExtension));
+            }
+
+            foreach (var subtitleFormat in subtitleFormats)
+            {
+                _logger.LogDebug(
+                    "Trying to parse '{FileExtension}' subtitle using the {SubtitleFormatParser} format parser",
+                    fileExtension,
+                    subtitleFormat.Name);
+                subtitleFormat.LoadSubtitle(subtitle, lines, fileExtension);
+                if (subtitleFormat.ErrorCount == 0)
+                {
+                    break;
+                }
+
+                _logger.LogError(
+                    "{ErrorCount} errors encountered while parsing '{FileExtension}' subtitle using the {SubtitleFormatParser} format parser",
+                    subtitleFormat.ErrorCount,
+                    fileExtension,
+                    subtitleFormat.Name);
+            }
+
+            if (subtitle.Paragraphs.Count == 0)
+            {
+                throw new ArgumentException("Unsupported format: " + fileExtension);
             }
 
             var trackInfo = new SubtitleTrackInfo();
@@ -57,5 +85,36 @@ namespace MediaBrowser.MediaEncoding.Subtitles
             trackInfo.TrackEvents = trackEvents;
             return trackInfo;
         }
+
+        /// <inheritdoc />
+        public bool SupportsFileExtension(string fileExtension)
+            => _subtitleFormats.ContainsKey(fileExtension);
+
+        private IEnumerable<SubtitleFormat> GetSubtitleFormats()
+        {
+            var subtitleFormats = new List<SubtitleFormat>();
+            var assembly = typeof(SubtitleFormat).Assembly;
+
+            foreach (var type in assembly.GetTypes())
+            {
+                if (!type.IsSubclassOf(typeof(SubtitleFormat)) || type.IsAbstract)
+                {
+                    continue;
+                }
+
+                try
+                {
+                    // It shouldn't be null, but the exception is caught if it is
+                    var subtitleFormat = (SubtitleFormat)Activator.CreateInstance(type, true)!;
+                    subtitleFormats.Add(subtitleFormat);
+                }
+                catch (Exception ex)
+                {
+                    _logger.LogWarning(ex, "Failed to create instance of the subtitle format {SubtitleFormatType}", type.Name);
+                }
+            }
+
+            return subtitleFormats;
+        }
     }
 }