--- /dev/null
+<?php
+
+use MediaWiki\Widget\UserInputWidget;
+
+/**
+ * Implements a text input field for user names.
+ * Automatically auto-completes if using the OOUI display format.
+ *
+ * FIXME: Does not work for forms that support GET requests.
+ *
+ * Optional parameters:
+ * 'exists' - Whether to validate that the user already exists
+ *
+ * @since 1.26
+ */
+class HTMLUserTextField extends HTMLTextField {
+ public function __construct( $params ) {
+ $params += [
+ 'exists' => false,
+ 'ipallowed' => false,
+ ];
+
+ parent::__construct( $params );
+ }
+
+ public function validate( $value, $alldata ) {
+ // check, if a user exists with the given username
+ $user = User::newFromName( $value, false );
+
+ if ( !$user ) {
+ return $this->msg( 'htmlform-user-not-valid', $value );
+ } elseif (
+ ( $this->mParams['exists'] && $user->getId() === 0 ) &&
+ !( $this->mParams['ipallowed'] && User::isIP( $value ) )
+ ) {
+ return $this->msg( 'htmlform-user-not-exists', $user->getName() );
+ }
+
+ return parent::validate( $value, $alldata );
+ }
+
+ protected function getInputWidget( $params ) {
+ return new UserInputWidget( $params );
+ }
+
+ protected function shouldInfuseOOUI() {
+ return true;
+ }
+
+ protected function getOOUIModules() {
+ return [ 'mediawiki.widgets.UserInputWidget' ];
+ }
+
+ public function getInputHtml( $value ) {
+ // add the required module and css class for user suggestions in non-OOUI mode
+ $this->mParent->getOutput()->addModules( 'mediawiki.userSuggest' );
+ $this->mClass .= ' mw-autocomplete-user';
+
+ // return parent html
+ return parent::getInputHTML( $value );
+ }
+}