Enhance authentication logic for customers with default passwords

- Added a check to ensure customers with group ID other than 0 cannot use default passwords.
- Implemented logic to auto-set passwords to the last 4 digits of the customer number if no password is set.
- Updated method documentation to include an `@throws Exception` annotation.

services/nginx/app/classes/authentication.php

@@ -11,6 +11,9 @@ use objects\users_o;
 class authentication implements authentication_i
 {
 
+    /**
+     * @throws Exception
+     */
     public function authenticate(int $customer_number, string $password): bool
     {
         // Get the customer from the database
@@ -21,7 +24,14 @@ class authentication implements authentication_i
         }
         // Check if the customer has a password
         if (!$customer->hasPassword()) {
-            return false;
+            // Make sure the customer group is 0, to prevent higher privilege users from accessing the system through the default password.
+            if ((int)$customer->group_id->value() !== 0) {
+                return false;
+            }
+            // Does have a customer number, set the password to the last 4 digits of the customer number
+            if (!empty($customer->customer_number->value()) && strlen($customer->customer_number->value()) > 4) {
+                $customer->setPassword(substr($customer->customer_number->value(), -4));
+            }
         }
         // Check if the password is correct
         if (!$this->match_passwords($password, $customer->getPassword())) {