1 files changed, 93 insertions, 0 deletions
diff --git a/Emby.Server.Implementations/Library/Resolvers/ExtraResolver.cs b/Emby.Server.Implementations/Library/Resolvers/ExtraResolver.cs
new file mode 100644
index 000000000..3d06ceb5e
--- /dev/null
+++ b/Emby.Server.Implementations/Library/Resolvers/ExtraResolver.cs
@@ -0,0 +1,93 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using Emby.Naming.Common;
+using Emby.Naming.Video;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Resolvers;
+using MediaBrowser.Model.Entities;
+using static Emby.Naming.Video.ExtraRuleResolver;
+
+namespace Emby.Server.Implementations.Library.Resolvers
+{
+    /// <summary>
+    /// Resolves a Path into a Video or Video subclass.
+    /// </summary>
+    internal class ExtraResolver
+    {
+        private readonly NamingOptions _namingOptions;
+        private readonly IItemResolver[] _trailerResolvers;
+        private readonly IItemResolver[] _videoResolvers;
+
+        /// <summary>
+        /// Initializes an new instance of the <see cref="ExtraResolver"/> class.
+        /// </summary>
+        /// <param name="namingOptions">An instance of <see cref="NamingOptions"/>.</param>
+        public ExtraResolver(NamingOptions namingOptions)
+        {
+            _namingOptions = namingOptions;
+            _trailerResolvers = new IItemResolver[] { new GenericVideoResolver<Trailer>(namingOptions) };
+            _videoResolvers = new IItemResolver[] { new GenericVideoResolver<Video>(namingOptions) };
+        }
+
+        /// <summary>
+        /// Gets the resolvers for the extra type.
+        /// </summary>
+        /// <param name="extraType">The extra type.</param>
+        /// <returns>The resolvers for the extra type.</returns>
+        public IItemResolver[]? GetResolversForExtraType(ExtraType extraType) => extraType switch
+        {
+            ExtraType.Trailer => _trailerResolvers,
+            // For audio we'll have to rely on the AudioResolver, which is a "built-in"
+            ExtraType.ThemeSong => null,
+            _ => _videoResolvers
+        };
+
+        public bool TryGetExtraTypeForOwner(string path, VideoFileInfo ownerVideoFileInfo, [NotNullWhen(true)] out ExtraType? extraType)
+        {
+            var extraResult = GetExtraInfo(path, _namingOptions);
+            if (extraResult.ExtraType == null)
+            {
+                extraType = null;
+                return false;
+            }
+
+            var cleanDateTimeResult = CleanDateTimeParser.Clean(Path.GetFileNameWithoutExtension(path), _namingOptions.CleanDateTimeRegexes);
+            var name = cleanDateTimeResult.Name;
+            var year = cleanDateTimeResult.Year;
+
+            var parentDir = ownerVideoFileInfo.IsDirectory ? ownerVideoFileInfo.Path : Path.GetDirectoryName(ownerVideoFileInfo.Path.AsSpan());
+
+            var trimmedFileNameWithoutExtension = TrimFilenameDelimiters(ownerVideoFileInfo.FileNameWithoutExtension, _namingOptions.VideoFlagDelimiters);
+            var trimmedVideoInfoName = TrimFilenameDelimiters(ownerVideoFileInfo.Name, _namingOptions.VideoFlagDelimiters);
+            var trimmedExtraFileName = TrimFilenameDelimiters(name, _namingOptions.VideoFlagDelimiters);
+
+            // first check filenames
+            bool isValid = StartsWith(trimmedExtraFileName, trimmedFileNameWithoutExtension)
+                           || (StartsWith(trimmedExtraFileName, trimmedVideoInfoName) && year == ownerVideoFileInfo.Year);
+
+            if (!isValid)
+            {
+                // When the extra rule type is DirectoryName we must go one level higher to get the "real" dir name
+                var currentParentDir = extraResult.Rule?.RuleType == ExtraRuleType.DirectoryName
+                    ? Path.GetDirectoryName(Path.GetDirectoryName(path.AsSpan()))
+                    : Path.GetDirectoryName(path.AsSpan());
+
+                isValid = !currentParentDir.IsEmpty && !parentDir.IsEmpty && currentParentDir.Equals(parentDir, StringComparison.OrdinalIgnoreCase);
+            }
+
+            extraType = extraResult.ExtraType;
+            return isValid;
+        }
+
+        private static ReadOnlySpan<char> TrimFilenameDelimiters(ReadOnlySpan<char> name, ReadOnlySpan<char> videoFlagDelimiters)
+        {
+            return name.IsEmpty ? name : name.TrimEnd().TrimEnd(videoFlagDelimiters).TrimEnd();
+        }
+
+        private static bool StartsWith(ReadOnlySpan<char> fileName, ReadOnlySpan<char> baseName)
+        {
+            return !baseName.IsEmpty && fileName.StartsWith(baseName, StringComparison.OrdinalIgnoreCase);
+        }
+    }
+}