1 files changed, 10 insertions, 2 deletions
diff --git a/Psso/Challenge/Username.php b/Psso/Challenge/Username.php
index 43de085..c8fa762 100644
--- a/Psso/Challenge/Username.php
+++ b/Psso/Challenge/Username.php
@@ -1,6 +1,6 @@
 <?php
 namespace Psso\Challenge;
-use Psso\{Challenge, AuthProvider, ChallengeResult, Input};
+use Psso\{Challenge, AuthProvider, AuthInterface, ChallengeResult, Input};
 
 /** Just asks for a username and sets it in the context. Always succeeds. */
 class Username extends Challenge {
@@ -11,6 +11,14 @@ class Username extends Challenge {
     public function validate(
         AuthProvider $provider, array $inputData
     ): ChallengeResult {
-        return new ChallengeResult(self::class, true, $inputData['user'], null);
+        $success = true;
+        $message = null;
+        if ($provider instanceof AuthInterface\UserExists) {
+            $success = $provider->userExists($inputData['user']);
+            if (!$success) $message = 'challenge.message.wrong-username';
+        }
+        return new ChallengeResult(
+            self::class, $success, $inputData['user'], $message
+        );
     }
 }