wikimedia/mediawiki-extensions-Translate

<?php
declare( strict_types = 1 );

namespace MediaWiki\Extension\Translate\PageTranslation;

use MediaWiki\Title\Title;

/**
 * Contains logic to determine the new title of translatable pages and
 * dependent pages being moved
 * @author Niklas Laxström
 * @author Abijeet Patro
 * @license GPL-2.0-or-later
 * @since 2021.09
 */
class PageTitleRenamer {
    public const NO_ERROR = 0;
    public const UNKNOWN_PAGE = 1;
    public const NS_TALK_UNSUPPORTED = 2;
    public const RENAME_FAILED = 3;
    public const INVALID_TITLE = 4;

    private const IMPOSSIBLE = null;
    /** @var string[][] */
    private $map = [];

    public function __construct( Title $source, Title $target ) {
        $this->map[$source->getNamespace()] = [
            $target->getNamespace(),
            $source->getText(),
            $target->getText(),
        ];

        $sourceTalkPage = $source->getTalkPageIfDefined();
        $targetTalkPage = $target->getTalkPageIfDefined();
        if ( $sourceTalkPage ) {
            if ( !$targetTalkPage ) {
                $this->map[$sourceTalkPage->getNamespace()] = [
                    self::IMPOSSIBLE,
                    null,
                    null,
                ];
            } else {
                $this->map[$sourceTalkPage->getNamespace()] = [
                    $targetTalkPage->getNamespace(),
                    $source->getText(),
                    $target->getText(),
                ];
            }
        }

        $this->map[NS_TRANSLATIONS] = [
            NS_TRANSLATIONS,
            $source->getPrefixedText(),
            $target->getPrefixedText(),
        ];

        $this->map[NS_TRANSLATIONS_TALK] = [
            NS_TRANSLATIONS_TALK,
            $source->getPrefixedText(),
            $target->getPrefixedText(),
        ];
    }

    public function getNewTitle( Title $title ): Title {
        $instructions = $this->map[$title->getNamespace()] ?? null;
        if ( $instructions === null ) {
            throw new InvalidPageTitleRename(
                'Trying to move a page which is not part of the translatable page', self::UNKNOWN_PAGE
            );
        }

        [ $newNamespace, $search, $replace ] = $instructions;

        if ( $newNamespace === self::IMPOSSIBLE ) {
            throw new InvalidPageTitleRename(
                'Trying to move a talk page to a namespace which does not have talk pages',
                self::NS_TALK_UNSUPPORTED
            );
        }

        $oldTitleText = $title->getText();

        // Check if the old title matches the string being replaced, if so there is no
        // need to run preg_replace. This will happen if the page is being moved from
        // one namespace to another.
        if ( $oldTitleText === $replace ) {
            return Title::makeTitleSafe( $newNamespace, $replace );
        }

        $searchQuoted = preg_quote( $search, '~' );
        $newText = preg_replace( "~^$searchQuoted~", $replace, $oldTitleText, 1 );

        // If old and new title + namespace are same, the renaming failed.
        if ( $oldTitleText === $newText && $newNamespace === $title->getNamespace() ) {
            throw new InvalidPageTitleRename( 'Renaming failed', self::RENAME_FAILED );
        }

        $title = Title::makeTitleSafe( $newNamespace, $newText );
        if ( $title === null ) {
            throw new InvalidPageTitleRename( 'Invalid target title', self::INVALID_TITLE );
        }

        return $title;
    }
}