Adapt welcome wallpaper to SGU gender

src/SGU.AuthBroker/Services/ActiveDirectorySynchronizer.cs

@@ -11,6 +11,8 @@ public sealed class ActiveDirectorySynchronizer(
     BrokerOptions options,
     ILogger<ActiveDirectorySynchronizer> logger) : IActiveDirectorySynchronizer
 {
+    private const string GenderMetadataPrefix = "SGU-Gender:";
+    private const int InfoAttributeMaximumLength = 1024;
     private const int AccountDisabled = 0x0002;
     private const int NormalAccount = 0x0200;
     private static readonly AuthenticationTypes BindFlags =
@@ -164,6 +166,7 @@ public sealed class ActiveDirectorySynchronizer(
                 SetOptionalProperty(user, "l", profile.City);
                 SetOptionalProperty(user, "st", profile.State);
                 SetOptionalProperty(user, "postalCode", profile.PostalCode);
+                SetGenderMetadata(user, profile.Gender, identity.UserName, logger);
                 if (string.Equals(profile.EmployeeNumber, identity.NumericId, StringComparison.Ordinal))
                 {
                     SetOptionalProperty(user, "employeeID", profile.EmployeeNumber);
@@ -201,6 +204,56 @@ public sealed class ActiveDirectorySynchronizer(
         }
     }
 
+    private static void SetGenderMetadata(
+        DirectoryEntry entry,
+        InstitutionalGender? gender,
+        string institutionalUser,
+        ILogger logger)
+    {
+        if (gender is null)
+        {
+            return;
+        }
+
+        string existing = Convert.ToString(entry.Properties["info"].Value) ?? string.Empty;
+        string? updated = MergeGenderMetadata(existing, gender);
+        if (updated is null)
+        {
+            logger.LogWarning(
+                BrokerEventIds.DirectoryOptionalMetadataFailure,
+                "Gender metadata was not written for {InstitutionalUser} because the Active Directory info attribute has no remaining capacity.",
+                institutionalUser);
+            return;
+        }
+
+        entry.Properties["info"].Value = updated;
+    }
+
+    internal static string? MergeGenderMetadata(
+        string? existing,
+        InstitutionalGender? gender)
+    {
+        if (gender is null)
+        {
+            return null;
+        }
+
+        string managedLine = $"{GenderMetadataPrefix} {gender}";
+        string normalizedExisting = (existing ?? string.Empty)
+            .Replace("\r\n", "\n", StringComparison.Ordinal)
+            .Replace('\r', '\n');
+        string[] preservedLines = string.IsNullOrEmpty(normalizedExisting)
+            ? []
+            : normalizedExisting
+            .Split('\n')
+            .Where(line => !line.TrimStart().StartsWith(
+                GenderMetadataPrefix,
+                StringComparison.OrdinalIgnoreCase))
+            .ToArray();
+        string updated = string.Join("\r\n", preservedLines.Append(managedLine));
+        return updated.Length <= InfoAttributeMaximumLength ? updated : null;
+    }
+
     private void EnsureRoleGroupMembership(DirectoryEntry user, UserIdentity identity)
     {
         user.RefreshCache(["distinguishedName"]);