<?php
/**
 * Deletes all pages in the MediaWiki namespace which were last edited by
 * "MediaWiki default".
 *
 * @license GPL-2.0-or-later
 * @file
 * @ingroup Maintenance
 */

// @codeCoverageIgnoreStart
require_once __DIR__ . '/Maintenance.php';
// @codeCoverageIgnoreEnd

use MediaWiki\Maintenance\Maintenance;
use MediaWiki\StubObject\StubGlobalUser;
use MediaWiki\Title\Title;
use MediaWiki\User\ActorMigration;
use MediaWiki\User\User;

/**
 * Maintenance script that deletes all pages in the MediaWiki namespace
 * which were last edited by "MediaWiki default".
 *
 * @ingroup Maintenance
 */
class DeleteDefaultMessages extends Maintenance {
	public function __construct() {
		parent::__construct();
		$this->addDescription( 'Deletes all pages in the MediaWiki namespace' .
			' which were last edited by "MediaWiki default"' );
		$this->addOption( 'dry-run', 'Perform a dry run, delete nothing' );
	}

	public function execute() {
		$services = $this->getServiceContainer();

		$this->output( "Checking existence of old default messages..." );
		$dbr = $this->getReplicaDB();

		$userFactory = $services->getUserFactory();
		$actorQuery = ActorMigration::newMigration()
			->getWhere( $dbr, 'rev_user', $userFactory->newFromName( 'MediaWiki default' ) );

		$res = $dbr->newSelectQueryBuilder()
			->select( [ 'page_namespace', 'page_title' ] )
			->from( 'page' )
			->join( 'revision', null, 'page_latest=rev_id' )
			->tables( $actorQuery['tables'] )
			->where( [
				'page_namespace' => NS_MEDIAWIKI,
				$actorQuery['conds'],
			] )
			->joinConds( $actorQuery['joins'] )
			->caller( __METHOD__ )
			->fetchResultSet();

		if ( $res->numRows() == 0 ) {
			// No more messages left
			$this->output( "done.\n" );
			return;
		}

		$dryrun = $this->hasOption( 'dry-run' );
		if ( $dryrun ) {
			foreach ( $res as $row ) {
				$title = Title::makeTitle( $row->page_namespace, $row->page_title );
				$this->output( "\n* [[$title]]" );
			}
			$this->output( "\n\nRun again without --dry-run to delete these pages.\n" );
			return;
		}

		// Deletions will be made by $user temporarily added to the bot group
		// in order to hide it in RecentChanges.
		$user = User::newSystemUser( 'MediaWiki default', [ 'steal' => true ] );
		if ( !$user ) {
			$this->fatalError( "Invalid username" );
		}
		$userGroupManager = $services->getUserGroupManager();
		$userGroupManager->addUserToGroup( $user, 'bot' );
		StubGlobalUser::setUser( $user );

		// Handle deletion
		$this->output( "\n...deleting old default messages (this may take a long time!)...", 'msg' );
		$dbw = $this->getPrimaryDB();

		$wikiPageFactory = $services->getWikiPageFactory();
		$delPageFactory = $services->getDeletePageFactory();

		foreach ( $res as $row ) {
			$this->waitForReplication();
			$dbw->ping();
			$title = Title::makeTitle( $row->page_namespace, $row->page_title );
			$page = $wikiPageFactory->newFromTitle( $title );
			// FIXME: Deletion failures should be reported, not silently ignored.
			$delPageFactory->newDeletePage( $page, $user )->deleteUnsafe( 'No longer required' );
		}

		$this->output( "done!\n", 'msg' );
	}
}

// @codeCoverageIgnoreStart
$maintClass = DeleteDefaultMessages::class;
require_once RUN_MAINTENANCE_IF_MAIN;
// @codeCoverageIgnoreEnd
