Update New-CIPPGroup.ps1 - allow blank usernames, generate GUID

Author: isgq-github01

Modules/CIPPCore/Public/New-CIPPGroup.ps1

@@ -77,32 +77,11 @@ function New-CIPPGroup {
             $null
         }
 
-        # Determine if we should generate a random mailNickname:
-        # For Security/Generic groups WITHOUT a username filled in
-        $ShouldGenerateRandomMailNickname = ($NormalizedGroupType -in @('Generic', 'Security')) -and [string]::IsNullOrWhiteSpace($GroupObject.username)
-
-        # Extract local part of username if exists and remove special characters for mailNickname
-        if ($ShouldGenerateRandomMailNickname) {
-            # Generate a random alphanumeric mailNickname for security groups without a username
-            # Format: 8 hex characters + hyphen + 1 hex character (e.g., "450662e4-3")
-            $RandomPart1 = -join ((0..7) | ForEach-Object { (0..15 | ForEach-Object { '0123456789abcdef'[$_] } | Get-Random) })
-            $RandomPart2 = (0..15 | ForEach-Object { '0123456789abcdef'[$_] } | Get-Random)
-            $MailNickname = "$RandomPart1-$RandomPart2"
+        # Determine if we should generate a mailNickname with a GUID, or use the username field
+        if (-not $GroupObject.Username) {
+            $MailNickname = (New-Guid).guid.substring(0, 10)
         } else {
-            if ($GroupObject.username) {
-                $MailNickname = ($GroupObject.username -split '@')[0]
-            } else {
-                $MailNickname = $GroupObject.username
-            }
-
-            # Remove forbidden characters per Microsoft 365 mailNickname requirements:
-            # ASCII 0-127 only, excluding: @ () / [] ' ; : <> , SPACE and any non-ASCII
-            $MailNickname = $MailNickname -replace "[@()\[\]/'`;:<>,\s]|[^\x00-\x7F]", ''
-
-            # Ensure max length of 64 characters
-            if ($MailNickname.Length -gt 64) {
-                $MailNickname = $MailNickname.Substring(0, 64)
-            }
+            $MailNickname = $GroupObject.Username
         }
 
         Write-LogMessage -API $APIName -tenant $TenantFilter -message "Creating group $($GroupObject.displayName) of type $NormalizedGroupType$(if ($NeedsEmail) { " with email $Email" })" -Sev Info