fix(metadata): normalize accents and add fuzzy suffix matching for games

Jellyfin/backend/Services/GameThumbService.cs

@@ -149,9 +149,9 @@ private static string BuildUrl(string platform, ThumbKind kind, string name) =>
     /// minus the extension. This is the filename rather than the display title, which for a game
     /// in its own folder is the folder name and would not match.
     /// </summary>
-    private static string LibretroThumbName(string romFileName)
+    private static string LibretroThumbName(string name)
     {
-        var chars = (Path.GetFileNameWithoutExtension(romFileName) ?? string.Empty).ToCharArray();
+        var chars = name.ToCharArray();
         for (var i = 0; i < chars.Length; i++)
         {
             if (Array.IndexOf(ReservedChars, chars[i]) >= 0)

Jellyfin/backend/Services/GamesService.cs

@@ -515,7 +515,13 @@ public IReadOnlyList<GameSummary> GetGames(string libraryId, string? systemId)
         var systemDir = FindSystemDir(library, romPath);
         var systemName = systemDir == null ? string.Empty : Path.GetFileName(systemDir);
         var core = ResolveSystemCore(systemName, new List<string> { romPath });
-        return (core, Path.GetFileName(romPath));
+
+        // Resolve the exact No-Intro name from Rdb if available so region codes and tags (like (USA)) are included in the art URL.
+        var title = ResolveTitle(systemDir, romPath);
+        var rdb = _rdb?.TryLookup(core, romPath, title);
+        var name = rdb?.Name ?? Path.GetFileNameWithoutExtension(romPath);
+
+        return (core, name);
     }
 
     /// <summary>

Jellyfin/backend/Services/RdbService.cs

@@ -1,5 +1,7 @@
 using System.Collections.Concurrent;
+using System.Globalization;
 using System.Net.Http;
+using System.Text;
 using Microsoft.Extensions.Logging;
 
 namespace Moonfin.Server.Services;
@@ -152,6 +154,40 @@ public RdbService(IHttpClientFactory httpClientFactory, ILogger<RdbService> logg
             }
         }
 
+        // Fallback when the exact match misses: take the closest name where one
+        // side is a prefix of the other, to absorb region or edition suffixes.
+        // Rdb keeps region parentheticals, so it allows a wider gap than LaunchBox.
+        if (fileName.Length >= 5)
+        {
+            RdbRecord? bestRecord = null;
+            var minDiff = int.MaxValue;
+            var ambiguous = false;
+            foreach (var kv in index.ByName)
+            {
+                if (kv.Key.StartsWith(fileName, StringComparison.Ordinal) ||
+                    fileName.StartsWith(kv.Key, StringComparison.Ordinal))
+                {
+                    var diff = Math.Abs(kv.Key.Length - fileName.Length);
+                    if (diff < minDiff)
+                    {
+                        minDiff = diff;
+                        bestRecord = kv.Value;
+                        ambiguous = false;
+                    }
+                    else if (diff == minDiff && !ReferenceEquals(kv.Value, bestRecord))
+                    {
+                        // Two different games are equally close, so a common prefix
+                        // can't be resolved to one. Skip rather than pick wrong art.
+                        ambiguous = true;
+                    }
+                }
+            }
+            if (bestRecord != null && !ambiguous && minDiff <= 45)
+            {
+                return bestRecord;
+            }
+        }
+
         return null;
     }
 
@@ -350,9 +386,16 @@ private static uint[] BuildCrcTable()
 
     private static string NormalizeName(string value)
     {
+        var normalizedString = value.Normalize(NormalizationForm.FormD);
         var sb = new System.Text.StringBuilder(value.Length);
-        foreach (var ch in value)
+        foreach (var ch in normalizedString)
         {
+            var unicodeCategory = CharUnicodeInfo.GetUnicodeCategory(ch);
+            if (unicodeCategory == UnicodeCategory.NonSpacingMark)
+            {
+                continue;
+            }
+
             if (char.IsLetterOrDigit(ch))
             {
                 sb.Append(char.ToLowerInvariant(ch));