Refactor SeasonalsPlugin: Simplify script injection logic (v1.5.0.0)

Jellyfin.Plugin.Seasonals/Helpers/TransformationPatches.cs

@@ -0,0 +1,49 @@
+using System;
+using Jellyfin.Plugin.Seasonals.Model;
+
+namespace Jellyfin.Plugin.Seasonals.Helpers
+{
+    public static class TransformationPatches
+    {
+        public static string IndexHtml(PatchRequestPayload payload)
+        {
+            // Always return original content if something fails or is null
+            string? originalContents = payload?.Contents;
+            
+            if (string.IsNullOrEmpty(originalContents))
+            {
+                return originalContents ?? string.Empty;
+            }
+
+            try
+            {
+                
+                // Safety Check: If plugin is disabled, do nothing
+                if (SeasonalsPlugin.Instance?.Configuration.IsEnabled != true)
+                {
+                    return originalContents;
+                }
+
+                // Use StringBuilder for efficient modification
+                var builder = new System.Text.StringBuilder(originalContents);
+
+                // Inject Script if missing
+                if (!originalContents.Contains("seasonals.js", StringComparison.Ordinal))
+                {
+                    var scriptIndex = originalContents.LastIndexOf(ScriptInjector.ScriptMarker, StringComparison.OrdinalIgnoreCase);
+                    if (scriptIndex != -1)
+                    {
+                        builder.Insert(scriptIndex, ScriptInjector.ScriptTag + Environment.NewLine);
+                    }
+                }
+                
+                return builder.ToString();
+            }
+            catch
+            {
+                // On error, return original content to avoid breaking the UI
+                return originalContents;
+            }
+        }
+    }
+}