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: 7323ccfc232d31797af3ceb8bad93cae1ea0898d

6 files changed, 89 insertions, 112 deletions

diff --git a/MediaBrowser.MediaEncoding/Subtitles/AssParser.cs b/MediaBrowser.MediaEncoding/Subtitles/AssParser.cs
deleted file mode 100644
index 08ee5c72e..000000000
--- a/MediaBrowser.MediaEncoding/Subtitles/AssParser.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-using Microsoft.Extensions.Logging;
-using Nikse.SubtitleEdit.Core.SubtitleFormats;
-
-namespace MediaBrowser.MediaEncoding.Subtitles
-{
-    /// <summary>
-    /// Advanced SubStation Alpha subtitle parser.
-    /// </summary>
-    public class AssParser : SubtitleEditParser<AdvancedSubStationAlpha>
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="AssParser"/> class.
-        /// </summary>
-        /// <param name="logger">The logger.</param>
-        public AssParser(ILogger logger) : base(logger)
-        {
-        }
-    }
-}
diff --git a/MediaBrowser.MediaEncoding/Subtitles/ISubtitleParser.cs b/MediaBrowser.MediaEncoding/Subtitles/ISubtitleParser.cs
index c0023ebf2..bd13437fb 100644
--- a/MediaBrowser.MediaEncoding/Subtitles/ISubtitleParser.cs
+++ b/MediaBrowser.MediaEncoding/Subtitles/ISubtitleParser.cs
@@ -1,7 +1,6 @@
 #pragma warning disable CS1591
 
 using System.IO;
-using System.Threading;
 using MediaBrowser.Model.MediaInfo;
 
 namespace MediaBrowser.MediaEncoding.Subtitles
@@ -12,8 +11,15 @@ namespace MediaBrowser.MediaEncoding.Subtitles
         /// Parses the specified stream.
         /// </summary>
         /// <param name="stream">The stream.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <param name="fileExtension">The file extension.</param>
         /// <returns>SubtitleTrackInfo.</returns>
-        SubtitleTrackInfo Parse(Stream stream, CancellationToken cancellationToken);
+        SubtitleTrackInfo Parse(Stream stream, string fileExtension);
+
+        /// <summary>
+        /// Determines whether the file extension is supported by the parser.
+        /// </summary>
+        /// <param name="fileExtension">The file extension.</param>
+        /// <returns>A value indicating whether the file extension is supported.</returns>
+        bool SupportsFileExtension(string fileExtension);
     }
 }
diff --git a/MediaBrowser.MediaEncoding/Subtitles/SrtParser.cs b/MediaBrowser.MediaEncoding/Subtitles/SrtParser.cs
deleted file mode 100644
index 78d54ca51..000000000
--- a/MediaBrowser.MediaEncoding/Subtitles/SrtParser.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-using Microsoft.Extensions.Logging;
-using Nikse.SubtitleEdit.Core.SubtitleFormats;
-
-namespace MediaBrowser.MediaEncoding.Subtitles
-{
-    /// <summary>
-    /// SubRip subtitle parser.
-    /// </summary>
-    public class SrtParser : SubtitleEditParser<SubRip>
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="SrtParser"/> class.
-        /// </summary>
-        /// <param name="logger">The logger.</param>
-        public SrtParser(ILogger logger) : base(logger)
-        {
-        }
-    }
-}
diff --git a/MediaBrowser.MediaEncoding/Subtitles/SsaParser.cs b/MediaBrowser.MediaEncoding/Subtitles/SsaParser.cs
deleted file mode 100644
index 17c2ae40e..000000000
--- a/MediaBrowser.MediaEncoding/Subtitles/SsaParser.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-using Microsoft.Extensions.Logging;
-using Nikse.SubtitleEdit.Core.SubtitleFormats;
-
-namespace MediaBrowser.MediaEncoding.Subtitles
-{
-    /// <summary>
-    /// SubStation Alpha subtitle parser.
-    /// </summary>
-    public class SsaParser : SubtitleEditParser<SubStationAlpha>
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="SsaParser"/> class.
-        /// </summary>
-        /// <param name="logger">The logger.</param>
-        public SsaParser(ILogger logger) : base(logger)
-        {
-        }
-    }
-}
diff --git a/MediaBrowser.MediaEncoding/Subtitles/SubtitleEditParser.cs b/MediaBrowser.MediaEncoding/Subtitles/SubtitleEditParser.cs
index 52c1b6467..eb8ff9624 100644
--- a/MediaBrowser.MediaEncoding/Subtitles/SubtitleEditParser.cs
+++ b/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))
+            {
+                throw new ArgumentException($"Unsupported file extension: {fileExtension}", nameof(fileExtension));
+            }
+
+            foreach (var subtitleFormat in subtitleFormats)
             {
-                _logger.LogError("{ErrorCount} errors encountered while parsing subtitle", subRip.ErrorCount);
+                _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;
+        }
     }
 }
diff --git a/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs b/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs
index 7091af734..50c4d9210 100644
--- a/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs
+++ b/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs
@@ -35,6 +35,7 @@ namespace MediaBrowser.MediaEncoding.Subtitles
         private readonly IMediaEncoder _mediaEncoder;
         private readonly IHttpClientFactory _httpClientFactory;
         private readonly IMediaSourceManager _mediaSourceManager;
+        private readonly ISubtitleParser _subtitleParser;
 
         /// <summary>
         /// The _semaphoreLocks.
@@ -48,7 +49,8 @@ namespace MediaBrowser.MediaEncoding.Subtitles
             IFileSystem fileSystem,
             IMediaEncoder mediaEncoder,
             IHttpClientFactory httpClientFactory,
-            IMediaSourceManager mediaSourceManager)
+            IMediaSourceManager mediaSourceManager,
+            ISubtitleParser subtitleParser)
         {
             _logger = logger;
             _appPaths = appPaths;
@@ -56,6 +58,7 @@ namespace MediaBrowser.MediaEncoding.Subtitles
             _mediaEncoder = mediaEncoder;
             _httpClientFactory = httpClientFactory;
             _mediaSourceManager = mediaSourceManager;
+            _subtitleParser = subtitleParser;
         }
 
         private string SubtitleCachePath => Path.Combine(_appPaths.DataPath, "subtitles");
@@ -73,8 +76,7 @@ namespace MediaBrowser.MediaEncoding.Subtitles
 
             try
             {
-                var reader = GetReader(inputFormat);
-                var trackInfo = reader.Parse(stream, cancellationToken);
+                var trackInfo = _subtitleParser.Parse(stream, inputFormat);
 
                 FilterEvents(trackInfo, startTimeTicks, endTimeTicks, preserveOriginalTimestamps);
 
@@ -233,7 +235,8 @@ namespace MediaBrowser.MediaEncoding.Subtitles
             var currentFormat = (Path.GetExtension(subtitleStream.Path) ?? subtitleStream.Codec)
                 .TrimStart('.');
 
-            if (!TryGetReader(currentFormat, out _))
+            // Fallback to ffmpeg conversion
+            if (!_subtitleParser.SupportsFileExtension(currentFormat))
             {
                 // Convert
                 var outputPath = GetSubtitleCachePath(mediaSource, subtitleStream.Index, ".srt");
@@ -243,44 +246,10 @@ namespace MediaBrowser.MediaEncoding.Subtitles
                 return new SubtitleInfo(outputPath, MediaProtocol.File, "srt", true);
             }
 
-            // It's possbile that the subtitleStream and mediaSource don't share the same protocol (e.g. .STRM file with local subs)
+            // It's possible that the subtitleStream and mediaSource don't share the same protocol (e.g. .STRM file with local subs)
             return new SubtitleInfo(subtitleStream.Path, _mediaSourceManager.GetPathProtocol(subtitleStream.Path), currentFormat, true);
         }
 
-        private bool TryGetReader(string format, [NotNullWhen(true)] out ISubtitleParser? value)
-        {
-            if (string.Equals(format, SubtitleFormat.SRT, StringComparison.OrdinalIgnoreCase))
-            {
-                value = new SrtParser(_logger);
-                return true;
-            }
-
-            if (string.Equals(format, SubtitleFormat.SSA, StringComparison.OrdinalIgnoreCase))
-            {
-                value = new SsaParser(_logger);
-                return true;
-            }
-
-            if (string.Equals(format, SubtitleFormat.ASS, StringComparison.OrdinalIgnoreCase))
-            {
-                value = new AssParser(_logger);
-                return true;
-            }
-
-            value = null;
-            return false;
-        }
-
-        private ISubtitleParser GetReader(string format)
-        {
-            if (TryGetReader(format, out var reader))
-            {
-                return reader;
-            }
-
-            throw new ArgumentException("Unsupported format: " + format);
-        }
-
         private bool TryGetWriter(string format, [NotNullWhen(true)] out ISubtitleWriter? value)
         {
             if (string.Equals(format, SubtitleFormat.ASS, StringComparison.OrdinalIgnoreCase))