Fix double-tagging when file already has a release prefix

Fansub descriptor brackets like [Multiple Subtitle] or [Dual Audio]
were being misread as release group names because their individual
words didn't match any known metadata pattern. This caused a bogus
tag to be stacked in front of files that already carried their own
[Group] prefix (e.g. Erai-raws releases).

- Recognize common multi-word fansub descriptors (Multi(ple) Sub(s),
  Dual/Multi Audio, Hard/Soft sub, Uncensored/Batch/Complete, etc.)
  as metadata via whole-phrase matching in IsMetadataBracket.
- Never prepend a derived release tag when the file's own filename
  already starts with a different bracket prefix, preventing any
  tag from being stacked on top of an existing one.

Futonizer.csproj

@@ -9,8 +9,8 @@
     <ImplicitUsings>enable</ImplicitUsings>
     <AssemblyName>Futonizer</AssemblyName>
     <RootNamespace>Futonizer</RootNamespace>
-    <Version>1.0.9</Version>
-    <FileVersion>1.0.9.0</FileVersion>
+    <Version>1.0.10</Version>
+    <FileVersion>1.0.10.0</FileVersion>
     <ApplicationIcon>Assets\app.ico</ApplicationIcon>
   </PropertyGroup>
 

Services/FileNameHelper.cs

@@ -67,6 +67,19 @@ public static class FileNameHelper
         new(@"^(HDR|SDR|10bit|8bit|HDR10|DV|DoVi)$",                              RegexOptions.IgnoreCase | RegexOptions.Compiled), // HDR / bit-depth
     ];
 
+    // Whole-phrase fansub/release descriptor patterns, checked against an
+    // entire bracket's contents rather than word-by-word. Catches common
+    // multi-word descriptors (e.g. "Multiple Subtitle", "Dual Audio") whose
+    // individual words wouldn't otherwise match any MetadataPatterns entry,
+    // so they'd be mistaken for a release group name.
+    private static readonly Regex[] DescriptorPhrasePatterns =
+    [
+        new(@"^Multi(ple)?[\s-]?Sub(s|title|titles)?$", RegexOptions.IgnoreCase | RegexOptions.Compiled),
+        new(@"^(Dual|Multi)[\s-]?Audio$",                RegexOptions.IgnoreCase | RegexOptions.Compiled),
+        new(@"^(Hard|Soft)[\s-]?sub(s)?$",               RegexOptions.IgnoreCase | RegexOptions.Compiled),
+        new(@"^(Uncensored|Censored|Batch|Complete)$",   RegexOptions.IgnoreCase | RegexOptions.Compiled),
+    ];
+
     // -------------------------------------------------------------------------
 
     /// <summary>
@@ -95,6 +108,12 @@ public static class FileNameHelper
         string? folder     = Path.GetDirectoryName(sourceFilePath);
         string folderName  = string.IsNullOrEmpty(folder) ? "" : (Path.GetFileName(folder) ?? "");
 
+        // Capture the file's own pre-existing bracket prefix (if any) before any
+        // transformation below, so we never stack a second/different tag on top
+        // of a file that already carries its own release-group prefix.
+        var originalPrefixMatch = PrefixTagRegex.Match(stemNoExt);
+        string? originalPrefixTag = originalPrefixMatch.Success ? originalPrefixMatch.Groups[1].Value : null;
+
         // 1. Extract in-filename suffix tag and remove it from the stem.
         //    e.g. "...x264-DemiHuman" → tag="DemiHuman", stem="...x264"
         //    Only fires when the word right before the dash is itself a
@@ -172,13 +191,21 @@ public static class FileNameHelper
             }
         }
 
-        // 4. Prepend release tag if not already present.
+        // 4. Prepend release tag if not already present. Skip when the file
+        //    already carries its own (different) bracket prefix — never stack
+        //    a second tag on top of an existing one.
         if (!string.IsNullOrEmpty(tag))
+        {
+            bool differsFromOriginalTag = originalPrefixTag != null
+                && !string.Equals(originalPrefixTag, tag, StringComparison.OrdinalIgnoreCase);
+
+            if (!differsFromOriginalTag)
             {
                 string tagPrefix = $"[{tag}]";
                 if (!fileName.StartsWith(tagPrefix, StringComparison.OrdinalIgnoreCase))
                     fileName = tagPrefix + " " + fileName;
             }
+        }
 
         return fileName;
     }
@@ -258,7 +285,10 @@ public static class FileNameHelper
     /// </summary>
     private static bool IsMetadataBracket(string content)
     {
-        var parts = content.Split(new[] { ' ', '-' }, StringSplitOptions.RemoveEmptyEntries);
+        string trimmed = content.Trim();
+        if (DescriptorPhrasePatterns.Any(p => p.IsMatch(trimmed))) return true;
+
+        var parts = trimmed.Split(new[] { ' ', '-' }, StringSplitOptions.RemoveEmptyEntries);
         return parts.Length > 0 && parts.All(IsMetadataToken);
     }
 }