<?php

/**
 * SCSSPHP
 *
 * @copyright 2012-2020 Leaf Corcoran
 *
 * @license http://opensource.org/licenses/MIT MIT
 *
 * @link http://scssphp.github.io/scssphp
 */

namespace ScssPhpRBE\ScssPhp\Ast\Selector;

use ScssPhpRBE\ScssPhp\Util\Character;
use ScssPhpRBE\ScssPhp\Visitor\SelectorVisitor;

/**
 * A placeholder selector.
 *
 * This doesn't match any elements. It's intended to be extended using
 * `@extend`. It's not a plain CSS selector—it should be removed before
 * emitting a CSS document.
 */
final class PlaceholderSelector extends SimpleSelector
{
    /**
     * The name of the placeholder.
     *
     * @var string
     * @readonly
     */
    private $name;

    public function __construct(string $name)
    {
        $this->name = $name;
    }

    public function getName(): string
    {
        return $this->name;
    }

    public function isInvisible(): bool
    {
        return true;
    }

    /**
     * Returns whether this is a private selector (that is, whether it begins
     * with `-` or `_`).
     */
    public function isPrivate(): bool
    {
        return Character::isPrivate($this->name);
    }

    public function accept(SelectorVisitor $visitor)
    {
        return $visitor->visitPlaceholderSelector($this);
    }

    public function addSuffix(string $suffix): SimpleSelector
    {
        return new PlaceholderSelector($this->name . $suffix);
    }

    public function equals(object $other): bool
    {
        return $other instanceof PlaceholderSelector && $other->name === $this->name;
    }
}
