HTMLFormField.php

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<?php

abstract class HTMLFormField {
    public $mParams;

    protected $mValidationCallback;
    protected $mFilterCallback;
    protected $mName;
    protected $mDir;
    protected $mLabel; # String label, as HTML. Set on construction.
    protected $mID;
    protected $mClass = '';
    protected $mVFormClass = '';
    protected $mHelpClass = false;
    protected $mDefault;
    protected $mOptions = false;
    protected $mOptionsLabelsNotFromMessage = false;
    protected $mHideIf = null;

    protected $mShowEmptyLabels = true;

    public $mParent;

    abstract function getInputHTML( $value );

    function getInputOOUI( $value ) {
        return false;
    }

    public function canDisplayErrors() {
        return $this->hasVisibleOutput();
    }

    function msg() {
        $args = func_get_args();

        if ( $this->mParent ) {
            $callback = [ $this->mParent, 'msg' ];
        } else {
            $callback = 'wfMessage';
        }

        return call_user_func_array( $callback, $args );
    }

    public function hasVisibleOutput() {
        return true;
    }

    protected function getNearestFieldByName( $alldata, $name ) {
        $tmp = $this->mName;
        $thisKeys = [];
        while ( preg_match( '/^(.+)\[([^\]]+)\]$/', $tmp, $m ) ) {
            array_unshift( $thisKeys, $m[2] );
            $tmp = $m[1];
        }
        if ( substr( $tmp, 0, 2 ) == 'wp' &&
            !array_key_exists( $tmp, $alldata ) &&
            array_key_exists( substr( $tmp, 2 ), $alldata )
        ) {
            // Adjust for name mangling.
            $tmp = substr( $tmp, 2 );
        }
        array_unshift( $thisKeys, $tmp );

        $tmp = $name;
        $nameKeys = [];
        while ( preg_match( '/^(.+)\[([^\]]+)\]$/', $tmp, $m ) ) {
            array_unshift( $nameKeys, $m[2] );
            $tmp = $m[1];
        }
        array_unshift( $nameKeys, $tmp );

        $testValue = '';
        for ( $i = count( $thisKeys ) - 1; $i >= 0; $i-- ) {
            $keys = array_merge( array_slice( $thisKeys, 0, $i ), $nameKeys );
            $data = $alldata;
            while ( $keys ) {
                $key = array_shift( $keys );
                if ( !is_array( $data ) || !array_key_exists( $key, $data ) ) {
                    continue 2;
                }
                $data = $data[$key];
            }
            $testValue = (string)$data;
            break;
        }

        return $testValue;
    }

    protected function isHiddenRecurse( array $alldata, array $params ) {
        $origParams = $params;
        $op = array_shift( $params );

        try {
            switch ( $op ) {
                case 'AND':
                    foreach ( $params as $i => $p ) {
                        if ( !is_array( $p ) ) {
                            throw new MWException(
                                "Expected array, found " . gettype( $p ) . " at index $i"
                            );
                        }
                        if ( !$this->isHiddenRecurse( $alldata, $p ) ) {
                            return false;
                        }
                    }
                    return true;

                case 'OR':
                    foreach ( $params as $i => $p ) {
                        if ( !is_array( $p ) ) {
                            throw new MWException(
                                "Expected array, found " . gettype( $p ) . " at index $i"
                            );
                        }
                        if ( $this->isHiddenRecurse( $alldata, $p ) ) {
                            return true;
                        }
                    }
                    return false;

                case 'NAND':
                    foreach ( $params as $i => $p ) {
                        if ( !is_array( $p ) ) {
                            throw new MWException(
                                "Expected array, found " . gettype( $p ) . " at index $i"
                            );
                        }
                        if ( !$this->isHiddenRecurse( $alldata, $p ) ) {
                            return true;
                        }
                    }
                    return false;

                case 'NOR':
                    foreach ( $params as $i => $p ) {
                        if ( !is_array( $p ) ) {
                            throw new MWException(
                                "Expected array, found " . gettype( $p ) . " at index $i"
                            );
                        }
                        if ( $this->isHiddenRecurse( $alldata, $p ) ) {
                            return false;
                        }
                    }
                    return true;

                case 'NOT':
                    if ( count( $params ) !== 1 ) {
                        throw new MWException( "NOT takes exactly one parameter" );
                    }
                    $p = $params[0];
                    if ( !is_array( $p ) ) {
                        throw new MWException(
                            "Expected array, found " . gettype( $p ) . " at index 0"
                        );
                    }
                    return !$this->isHiddenRecurse( $alldata, $p );

                case '===':
                case '!==':
                    if ( count( $params ) !== 2 ) {
                        throw new MWException( "$op takes exactly two parameters" );
                    }
                    list( $field, $value ) = $params;
                    if ( !is_string( $field ) || !is_string( $value ) ) {
                        throw new MWException( "Parameters for $op must be strings" );
                    }
                    $testValue = $this->getNearestFieldByName( $alldata, $field );
                    switch ( $op ) {
                        case '===':
                            return ( $value === $testValue );
                        case '!==':
                            return ( $value !== $testValue );
                    }

                default:
                    throw new MWException( "Unknown operation" );
            }
        } catch ( Exception $ex ) {
            throw new MWException(
                "Invalid hide-if specification for $this->mName: " .
                $ex->getMessage() . " in " . var_export( $origParams, true ),
                0, $ex
            );
        }
    }

    function isHidden( $alldata ) {
        if ( !$this->mHideIf ) {
            return false;
        }

        return $this->isHiddenRecurse( $alldata, $this->mHideIf );
    }

    function cancelSubmit( $value, $alldata ) {
        return false;
    }

    function validate( $value, $alldata ) {
        if ( $this->isHidden( $alldata ) ) {
            return true;
        }

        if ( isset( $this->mParams['required'] )
            && $this->mParams['required'] !== false
            && $value === ''
        ) {
            return $this->msg( 'htmlform-required' )->parse();
        }

        if ( isset( $this->mValidationCallback ) ) {
            return call_user_func( $this->mValidationCallback, $value, $alldata, $this->mParent );
        }

        return true;
    }

    function filter( $value, $alldata ) {
        if ( isset( $this->mFilterCallback ) ) {
            $value = call_user_func( $this->mFilterCallback, $value, $alldata, $this->mParent );
        }

        return $value;
    }

    protected function needsLabel() {
        return true;
    }

    public function setShowEmptyLabel( $show ) {
        $this->mShowEmptyLabels = $show;
    }

    protected function isSubmitAttempt( WebRequest $request ) {
        return $request->getCheck( 'wpEditToken' ) || $request->getCheck( 'wpFormIdentifier' );
    }

    function loadDataFromRequest( $request ) {
        if ( $request->getCheck( $this->mName ) ) {
            return $request->getText( $this->mName );
        } else {
            return $this->getDefault();
        }
    }

    function __construct( $params ) {
        $this->mParams = $params;

        if ( isset( $params['parent'] ) && $params['parent'] instanceof HTMLForm ) {
            $this->mParent = $params['parent'];
        }

        # Generate the label from a message, if possible
        if ( isset( $params['label-message'] ) ) {
            $this->mLabel = $this->getMessage( $params['label-message'] )->parse();
        } elseif ( isset( $params['label'] ) ) {
            if ( $params['label'] === '&#160;' ) {
                // Apparently some things set &nbsp directly and in an odd format
                $this->mLabel = '&#160;';
            } else {
                $this->mLabel = htmlspecialchars( $params['label'] );
            }
        } elseif ( isset( $params['label-raw'] ) ) {
            $this->mLabel = $params['label-raw'];
        }

        $this->mName = "wp{$params['fieldname']}";
        if ( isset( $params['name'] ) ) {
            $this->mName = $params['name'];
        }

        if ( isset( $params['dir'] ) ) {
            $this->mDir = $params['dir'];
        }

        $validName = Sanitizer::escapeId( $this->mName );
        $validName = str_replace( [ '.5B', '.5D' ], [ '[', ']' ], $validName );
        if ( $this->mName != $validName && !isset( $params['nodata'] ) ) {
            throw new MWException( "Invalid name '{$this->mName}' passed to " . __METHOD__ );
        }

        $this->mID = "mw-input-{$this->mName}";

        if ( isset( $params['default'] ) ) {
            $this->mDefault = $params['default'];
        }

        if ( isset( $params['id'] ) ) {
            $id = $params['id'];
            $validId = Sanitizer::escapeId( $id );

            if ( $id != $validId ) {
                throw new MWException( "Invalid id '$id' passed to " . __METHOD__ );
            }

            $this->mID = $id;
        }

        if ( isset( $params['cssclass'] ) ) {
            $this->mClass = $params['cssclass'];
        }

        if ( isset( $params['csshelpclass'] ) ) {
            $this->mHelpClass = $params['csshelpclass'];
        }

        if ( isset( $params['validation-callback'] ) ) {
            $this->mValidationCallback = $params['validation-callback'];
        }

        if ( isset( $params['filter-callback'] ) ) {
            $this->mFilterCallback = $params['filter-callback'];
        }

        if ( isset( $params['hidelabel'] ) ) {
            $this->mShowEmptyLabels = false;
        }

        if ( isset( $params['hide-if'] ) ) {
            $this->mHideIf = $params['hide-if'];
        }
    }

    function getTableRow( $value ) {
        list( $errors, $errorClass ) = $this->getErrorsAndErrorClass( $value );
        $inputHtml = $this->getInputHTML( $value );
        $fieldType = get_class( $this );
        $helptext = $this->getHelpTextHtmlTable( $this->getHelpText() );
        $cellAttributes = [];
        $rowAttributes = [];
        $rowClasses = '';

        if ( !empty( $this->mParams['vertical-label'] ) ) {
            $cellAttributes['colspan'] = 2;
            $verticalLabel = true;
        } else {
            $verticalLabel = false;
        }

        $label = $this->getLabelHtml( $cellAttributes );

        $field = Html::rawElement(
            'td',
            [ 'class' => 'mw-input' ] + $cellAttributes,
            $inputHtml . "\n$errors"
        );

        if ( $this->mHideIf ) {
            $rowAttributes['data-hide-if'] = FormatJson::encode( $this->mHideIf );
            $rowClasses .= ' mw-htmlform-hide-if';
        }

        if ( $verticalLabel ) {
            $html = Html::rawElement( 'tr',
                $rowAttributes + [ 'class' => "mw-htmlform-vertical-label $rowClasses" ], $label );
            $html .= Html::rawElement( 'tr',
                $rowAttributes + [
                    'class' => "mw-htmlform-field-$fieldType {$this->mClass} $errorClass $rowClasses"
                ],
                $field );
        } else {
            $html =
                Html::rawElement( 'tr',
                    $rowAttributes + [
                        'class' => "mw-htmlform-field-$fieldType {$this->mClass} $errorClass $rowClasses"
                    ],
                    $label . $field );
        }

        return $html . $helptext;
    }

    public function getDiv( $value ) {
        list( $errors, $errorClass ) = $this->getErrorsAndErrorClass( $value );
        $inputHtml = $this->getInputHTML( $value );
        $fieldType = get_class( $this );
        $helptext = $this->getHelpTextHtmlDiv( $this->getHelpText() );
        $cellAttributes = [];
        $label = $this->getLabelHtml( $cellAttributes );

        $outerDivClass = [
            'mw-input',
            'mw-htmlform-nolabel' => ( $label === '' )
        ];

        $horizontalLabel = isset( $this->mParams['horizontal-label'] )
            ? $this->mParams['horizontal-label'] : false;

        if ( $horizontalLabel ) {
            $field = '&#160;' . $inputHtml . "\n$errors";
        } else {
            $field = Html::rawElement(
                'div',
                [ 'class' => $outerDivClass ] + $cellAttributes,
                $inputHtml . "\n$errors"
            );
        }
        $divCssClasses = [ "mw-htmlform-field-$fieldType",
            $this->mClass, $this->mVFormClass, $errorClass ];

        $wrapperAttributes = [
            'class' => $divCssClasses,
        ];
        if ( $this->mHideIf ) {
            $wrapperAttributes['data-hide-if'] = FormatJson::encode( $this->mHideIf );
            $wrapperAttributes['class'][] = ' mw-htmlform-hide-if';
        }
        $html = Html::rawElement( 'div', $wrapperAttributes, $label . $field );
        $html .= $helptext;

        return $html;
    }

    public function getOOUI( $value ) {
        $inputField = $this->getInputOOUI( $value );

        if ( !$inputField ) {
            // This field doesn't have an OOUI implementation yet at all. Fall back to getDiv() to
            // generate the whole field, label and errors and all, then wrap it in a Widget.
            // It might look weird, but it'll work OK.
            return $this->getFieldLayoutOOUI(
                new OOUI\Widget( [ 'content' => new OOUI\HtmlSnippet( $this->getDiv( $value ) ) ] ),
                [ 'infusable' => false, 'align' => 'top' ]
            );
        }

        $infusable = true;
        if ( is_string( $inputField ) ) {
            // We have an OOUI implementation, but it's not proper, and we got a load of HTML.
            // Cheat a little and wrap it in a widget. It won't be infusable, though, since client-side
            // JavaScript doesn't know how to rebuilt the contents.
            $inputField = new OOUI\Widget( [ 'content' => new OOUI\HtmlSnippet( $inputField ) ] );
            $infusable = false;
        }

        $fieldType = get_class( $this );
        $help = $this->getHelpText();
        $errors = $this->getErrorsRaw( $value );
        foreach ( $errors as &$error ) {
            $error = new OOUI\HtmlSnippet( $error );
        }

        $notices = $this->getNotices();
        foreach ( $notices as &$notice ) {
            $notice = new OOUI\HtmlSnippet( $notice );
        }

        $config = [
            'classes' => [ "mw-htmlform-field-$fieldType", $this->mClass ],
            'align' => $this->getLabelAlignOOUI(),
            'help' => ( $help !== null && $help !== '' ) ? new OOUI\HtmlSnippet( $help ) : null,
            'errors' => $errors,
            'notices' => $notices,
            'infusable' => $infusable,
        ];

        $preloadModules = false;

        if ( $infusable && $this->shouldInfuseOOUI() ) {
            $preloadModules = true;
            $config['classes'][] = 'mw-htmlform-field-autoinfuse';
        }

        // the element could specify, that the label doesn't need to be added
        $label = $this->getLabel();
        if ( $label ) {
            $config['label'] = new OOUI\HtmlSnippet( $label );
        }

        if ( $this->mHideIf ) {
            $preloadModules = true;
            $config['hideIf'] = $this->mHideIf;
        }

        $config['modules'] = $this->getOOUIModules();

        if ( $preloadModules ) {
            $this->mParent->getOutput()->addModules( 'mediawiki.htmlform.ooui' );
            $this->mParent->getOutput()->addModules( $this->getOOUIModules() );
        }

        return $this->getFieldLayoutOOUI( $inputField, $config );
    }

    protected function getLabelAlignOOUI() {
        return 'top';
    }

    protected function getFieldLayoutOOUI( $inputField, $config ) {
        if ( isset( $this->mClassWithButton ) ) {
            $buttonWidget = $this->mClassWithButton->getInputOOUI( '' );
            return new HTMLFormActionFieldLayout( $inputField, $buttonWidget, $config );
        }
        return new HTMLFormFieldLayout( $inputField, $config );
    }

    protected function shouldInfuseOOUI() {
        // Always infuse fields with help text, since the interface for it is nicer with JS
        return $this->getHelpText() !== null;
    }

    protected function getOOUIModules() {
        return [];
    }

    public function getRaw( $value ) {
        list( $errors, ) = $this->getErrorsAndErrorClass( $value );
        $inputHtml = $this->getInputHTML( $value );
        $helptext = $this->getHelpTextHtmlRaw( $this->getHelpText() );
        $cellAttributes = [];
        $label = $this->getLabelHtml( $cellAttributes );

        $html = "\n$errors";
        $html .= $label;
        $html .= $inputHtml;
        $html .= $helptext;

        return $html;
    }

    public function getVForm( $value ) {
        // Ewwww
        $this->mVFormClass = ' mw-ui-vform-field';
        return $this->getDiv( $value );
    }

    public function getInline( $value ) {
        list( $errors, $errorClass ) = $this->getErrorsAndErrorClass( $value );
        $inputHtml = $this->getInputHTML( $value );
        $helptext = $this->getHelpTextHtmlDiv( $this->getHelpText() );
        $cellAttributes = [];
        $label = $this->getLabelHtml( $cellAttributes );

        $html = "\n" . $errors .
            $label . '&#160;' .
            $inputHtml .
            $helptext;

        return $html;
    }

    public function getHelpTextHtmlTable( $helptext ) {
        if ( is_null( $helptext ) ) {
            return '';
        }

        $rowAttributes = [];
        if ( $this->mHideIf ) {
            $rowAttributes['data-hide-if'] = FormatJson::encode( $this->mHideIf );
            $rowAttributes['class'] = 'mw-htmlform-hide-if';
        }

        $tdClasses = [ 'htmlform-tip' ];
        if ( $this->mHelpClass !== false ) {
            $tdClasses[] = $this->mHelpClass;
        }
        $row = Html::rawElement( 'td', [ 'colspan' => 2, 'class' => $tdClasses ], $helptext );
        $row = Html::rawElement( 'tr', $rowAttributes, $row );

        return $row;
    }

    public function getHelpTextHtmlDiv( $helptext ) {
        if ( is_null( $helptext ) ) {
            return '';
        }

        $wrapperAttributes = [
            'class' => 'htmlform-tip',
        ];
        if ( $this->mHelpClass !== false ) {
            $wrapperAttributes['class'] .= " {$this->mHelpClass}";
        }
        if ( $this->mHideIf ) {
            $wrapperAttributes['data-hide-if'] = FormatJson::encode( $this->mHideIf );
            $wrapperAttributes['class'] .= ' mw-htmlform-hide-if';
        }
        $div = Html::rawElement( 'div', $wrapperAttributes, $helptext );

        return $div;
    }

    public function getHelpTextHtmlRaw( $helptext ) {
        return $this->getHelpTextHtmlDiv( $helptext );
    }

    public function getHelpText() {
        $helptext = null;

        if ( isset( $this->mParams['help-message'] ) ) {
            $this->mParams['help-messages'] = [ $this->mParams['help-message'] ];
        }

        if ( isset( $this->mParams['help-messages'] ) ) {
            foreach ( $this->mParams['help-messages'] as $msg ) {
                $msg = $this->getMessage( $msg );

                if ( $msg->exists() ) {
                    if ( is_null( $helptext ) ) {
                        $helptext = '';
                    } else {
                        $helptext .= $this->msg( 'word-separator' )->escaped(); // some space
                    }
                    $helptext .= $msg->parse(); // Append message
                }
            }
        } elseif ( isset( $this->mParams['help'] ) ) {
            $helptext = $this->mParams['help'];
        }

        return $helptext;
    }

    public function getErrorsAndErrorClass( $value ) {
        $errors = $this->validate( $value, $this->mParent->mFieldData );

        if ( is_bool( $errors ) || !$this->mParent->wasSubmitted() ) {
            $errors = '';
            $errorClass = '';
        } else {
            $errors = self::formatErrors( $errors );
            $errorClass = 'mw-htmlform-invalid-input';
        }

        return [ $errors, $errorClass ];
    }

    public function getErrorsRaw( $value ) {
        $errors = $this->validate( $value, $this->mParent->mFieldData );

        if ( is_bool( $errors ) || !$this->mParent->wasSubmitted() ) {
            $errors = [];
        }

        if ( !is_array( $errors ) ) {
            $errors = [ $errors ];
        }
        foreach ( $errors as &$error ) {
            if ( $error instanceof Message ) {
                $error = $error->parse();
            }
        }

        return $errors;
    }

    function getNotices() {
        $notices = [];

        if ( isset( $this->mParams['notice-message'] ) ) {
            $notices[] = $this->getMessage( $this->mParams['notice-message'] )->parse();
        }

        if ( isset( $this->mParams['notice-messages'] ) ) {
            foreach ( $this->mParams['notice-messages'] as $msg ) {
                $notices[] = $this->getMessage( $msg )->parse();
            }
        } elseif ( isset( $this->mParams['notice'] ) ) {
            $notices[] = $this->mParams['notice'];
        }

        return $notices;
    }

    function getLabel() {
        return is_null( $this->mLabel ) ? '' : $this->mLabel;
    }

    function getLabelHtml( $cellAttributes = [] ) {
        # Don't output a for= attribute for labels with no associated input.
        # Kind of hacky here, possibly we don't want these to be <label>s at all.
        $for = [];

        if ( $this->needsLabel() ) {
            $for['for'] = $this->mID;
        }

        $labelValue = trim( $this->getLabel() );
        $hasLabel = false;
        if ( $labelValue !== '&#160;' && $labelValue !== '' ) {
            $hasLabel = true;
        }

        $displayFormat = $this->mParent->getDisplayFormat();
        $html = '';
        $horizontalLabel = isset( $this->mParams['horizontal-label'] )
            ? $this->mParams['horizontal-label'] : false;

        if ( $displayFormat === 'table' ) {
            $html =
                Html::rawElement( 'td',
                    [ 'class' => 'mw-label' ] + $cellAttributes,
                    Html::rawElement( 'label', $for, $labelValue ) );
        } elseif ( $hasLabel || $this->mShowEmptyLabels ) {
            if ( $displayFormat === 'div' && !$horizontalLabel ) {
                $html =
                    Html::rawElement( 'div',
                        [ 'class' => 'mw-label' ] + $cellAttributes,
                        Html::rawElement( 'label', $for, $labelValue ) );
            } else {
                $html = Html::rawElement( 'label', $for, $labelValue );
            }
        }

        return $html;
    }

    function getDefault() {
        if ( isset( $this->mDefault ) ) {
            return $this->mDefault;
        } else {
            return null;
        }
    }

    public function getTooltipAndAccessKey() {
        if ( empty( $this->mParams['tooltip'] ) ) {
            return [];
        }

        return Linker::tooltipAndAccesskeyAttribs( $this->mParams['tooltip'] );
    }

    public function getAttributes( array $list ) {
        static $boolAttribs = [ 'disabled', 'required', 'autofocus', 'multiple', 'readonly' ];

        $ret = [];
        foreach ( $list as $key ) {
            if ( in_array( $key, $boolAttribs ) ) {
                if ( !empty( $this->mParams[$key] ) ) {
                    $ret[$key] = '';
                }
            } elseif ( isset( $this->mParams[$key] ) ) {
                $ret[$key] = $this->mParams[$key];
            }
        }

        return $ret;
    }

    private function lookupOptionsKeys( $options ) {
        $ret = [];
        foreach ( $options as $key => $value ) {
            $key = $this->msg( $key )->plain();
            $ret[$key] = is_array( $value )
                ? $this->lookupOptionsKeys( $value )
                : strval( $value );
        }
        return $ret;
    }

    static function forceToStringRecursive( $array ) {
        if ( is_array( $array ) ) {
            return array_map( [ __CLASS__, 'forceToStringRecursive' ], $array );
        } else {
            return strval( $array );
        }
    }

    public function getOptions() {
        if ( $this->mOptions === false ) {
            if ( array_key_exists( 'options-messages', $this->mParams ) ) {
                $this->mOptions = $this->lookupOptionsKeys( $this->mParams['options-messages'] );
            } elseif ( array_key_exists( 'options', $this->mParams ) ) {
                $this->mOptionsLabelsNotFromMessage = true;
                $this->mOptions = self::forceToStringRecursive( $this->mParams['options'] );
            } elseif ( array_key_exists( 'options-message', $this->mParams ) ) {
                $message = $this->getMessage( $this->mParams['options-message'] )->inContentLanguage()->plain();

                $optgroup = false;
                $this->mOptions = [];
                foreach ( explode( "\n", $message ) as $option ) {
                    $value = trim( $option );
                    if ( $value == '' ) {
                        continue;
                    } elseif ( substr( $value, 0, 1 ) == '*' && substr( $value, 1, 1 ) != '*' ) {
                        # A new group is starting...
                        $value = trim( substr( $value, 1 ) );
                        $optgroup = $value;
                    } elseif ( substr( $value, 0, 2 ) == '**' ) {
                        # groupmember
                        $opt = trim( substr( $value, 2 ) );
                        if ( $optgroup === false ) {
                            $this->mOptions[$opt] = $opt;
                        } else {
                            $this->mOptions[$optgroup][$opt] = $opt;
                        }
                    } else {
                        # groupless reason list
                        $optgroup = false;
                        $this->mOptions[$option] = $option;
                    }
                }
            } else {
                $this->mOptions = null;
            }
        }

        return $this->mOptions;
    }

    public function getOptionsOOUI() {
        $oldoptions = $this->getOptions();

        if ( $oldoptions === null ) {
            return null;
        }

        $options = [];

        foreach ( $oldoptions as $text => $data ) {
            $options[] = [
                'data' => (string)$data,
                'label' => (string)$text,
            ];
        }

        return $options;
    }

    public static function flattenOptions( $options ) {
        $flatOpts = [];

        foreach ( $options as $value ) {
            if ( is_array( $value ) ) {
                $flatOpts = array_merge( $flatOpts, self::flattenOptions( $value ) );
            } else {
                $flatOpts[] = $value;
            }
        }

        return $flatOpts;
    }

    protected static function formatErrors( $errors ) {
        if ( is_array( $errors ) && count( $errors ) === 1 ) {
            $errors = array_shift( $errors );
        }

        if ( is_array( $errors ) ) {
            $lines = [];
            foreach ( $errors as $error ) {
                if ( $error instanceof Message ) {
                    $lines[] = Html::rawElement( 'li', [], $error->parse() );
                } else {
                    $lines[] = Html::rawElement( 'li', [], $error );
                }
            }

            return Html::rawElement( 'ul', [ 'class' => 'error' ], implode( "\n", $lines ) );
        } else {
            if ( $errors instanceof Message ) {
                $errors = $errors->parse();
            }

            return Html::rawElement( 'span', [ 'class' => 'error' ], $errors );
        }
    }

    protected function getMessage( $value ) {
        $message = Message::newFromSpecifier( $value );

        if ( $this->mParent ) {
            $message->setContext( $this->mParent );
        }

        return $message;
    }

    public function skipLoadData( $request ) {
        return !empty( $this->mParams['nodata'] );
    }
}