<?php

namespace wcf\data;

use wcf\system\exception\ImplementationException;
use wcf\system\exception\SystemException;
use wcf\system\SingletonFactory;

/**
 * Abstract class for all processible data holder classes.
 *
 * @author  Marcel Werk
 * @copyright   2001-2019 WoltLab GmbH
 * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
 * @package WoltLabSuite\Core\Data
 *
 * @property-read   string|null $className  name of the PHP class whose object(s) act as processor
 */
class ProcessibleDatabaseObject extends DatabaseObject
{
    /**
     * name of the interface the processor of this database object should implement
     * @var string
     */
    protected static $processorInterface = '';

    /**
     * processor this database object
     * @var object
     */
    protected $processor;

    /**
     * Returns the processor this database object.
     *
     * @return  object
     * @throws  SystemException
     */
    public function getProcessor()
    {
        if ($this->processor === null) {
            if ($this->className) {
                if (!\class_exists($this->className)) {
                    throw new SystemException("Unable to find class '" . $this->className . "'");
                }
                if (!\is_subclass_of($this->className, static::$processorInterface)) {
                    throw new ImplementationException($this->className, static::$processorInterface);
                }

                if (\is_subclass_of($this->className, SingletonFactory::class)) {
                    $this->processor = \call_user_func([$this->className, 'getInstance']);
                } else {
                    if (!\is_subclass_of($this->className, IDatabaseObjectProcessor::class)) {
                        throw new ImplementationException($this->className, IDatabaseObjectProcessor::class);
                    }

                    $this->processor = new $this->className($this);
                }
            }
        }

        return $this->processor;
    }
}