reordered logic to check password before existing user

JabbR/Commands/CommandManager.cs

@@ -650,7 +650,7 @@ private void HandleNick(string[] parts)
                 {
                     if (String.IsNullOrEmpty(password))
                     {
-                        ChatService.ThrowUserExists(userName);
+                        ChatService.ThrowPasswordIsRequired();
                     }
                     else
                     {

JabbR/Services/ChatService.cs

@@ -24,6 +24,11 @@ public ChatUser AddUser(string userName, string clientId, string password)
                 throw new InvalidOperationException(String.Format("'{0}' is not a valid user name.", userName));
             }
 
+            if (String.IsNullOrEmpty(password))
+            {
+                ThrowPasswordIsRequired();
+            }
+
             EnsureUserNameIsAvailable(userName);
 
             var user = new ChatUser
@@ -35,11 +40,6 @@ public ChatUser AddUser(string userName, string clientId, string password)
                 LastActivity = DateTime.UtcNow
             };
 
-            if (String.IsNullOrEmpty(password))
-            {
-                throw new InvalidOperationException("A password is required.");
-            }
-
             ValidatePassword(password);
             user.HashedPassword = password.ToSha256(user.Salt);
 
@@ -331,6 +331,11 @@ internal static void ThrowUserExists(string userName)
             throw new InvalidOperationException(String.Format("Username {0} already taken, please pick a new one using '/nick nickname'.", userName));
         }
 
+        internal static void ThrowPasswordIsRequired()
+        {
+            throw new InvalidOperationException("A password is required.");
+        }
+
         internal static bool IsUserInRoom(ChatRoom room, ChatUser user)
         {
             return room.Users.Any(r => r.Name.Equals(user.Name, StringComparison.OrdinalIgnoreCase));