<?php
/**
 * A maintenance script that allows you to see if any documents in an
 * Elasticsearch index which are marked 'OK' actually do not have content
 * in their associated entry within Elasticsearch.  This can happen if the
 * index is somehow corrupted (during upgrade?).  If this type of corruptions
 * happens, you'll experience a lack of search results for content that is known
 * to be in the wiki.
 *
 * Elasticsearch will not index that 'missing' content until a new edit is
 * made to the page marked as 'OK'. This script
 * is possibly the only way (short of some jedi es query) for a MediaWiki admin
 * to see which wiki articles are affected by this "black hole" of search.
 *
 * To avoid changing any content, we attempt to make a 'null edit' for pages
 * affected by the situation. These edits do appear in RecentChanges, and can be
 * managed with other MediaWiki administrative tools.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Maintenance
 */


/**
 * This script is a maintenance script for CirrusSearch
 * @var [type]
 */
namespace CirrusSearch;

use CirrusSearch\Maintenance\Maintenance;
use Title;
use WikiPage;
use MediaWiki\MediaWikiServices;

$IP = getenv( 'MW_INSTALL_PATH' );
if ( $IP === false ) {
	$IP = __DIR__ . '/../../..';
}
require_once "$IP/maintenance/Maintenance.php";
require_once __DIR__ . '/../includes/Maintenance/Maintenance.php';


/**
 * Maintenance script to check articles to see if they are indexed by Elasticsearch.
 *
 * @ingroup Maintenance
 */
class PurgeUnindexedPages extends Maintenance {

	public function __construct() {
		parent::__construct();
		$this->addDescription( 'Check articles to see if they are indexed by Elasticsearch' );
		// $name, $description, $required = false, $withArg = false, $shortName = false, $multiOccurrence = false
		$this->addOption(
			'dry-run',
			'Do not perform any corrections/edits with "-n or --dry-run"',
			false,
			false,
			'n'
		);
		$this->addOption('verbose',
			'List the titles with "-v or --verbose"',
			false,
			false,
			'v'
		);
		$this->setBatchSize( 1000 ); // parent method; adds --batch-size option
	}

	public function execute() {
		global $wgUser;
		$start = ''; // what title starts the select statement
		$numArticles = 0; // how many articles are there?
		$numBad = 0; // how many bad articles did we find?
		// do not edit anything
		$this->mNope = ( $this->hasOption( 'dry-run' ) )? true : false;
		// print a list (and stats)
		$this->mVerbose = ( $this->hasOption( 'verbose' ) )? true: false;

		$config = MediaWikiServices::getInstance()->getConfigFactory()->makeConfig( 'CirrusSearch' );
		$conn = new Connection( $config );
		$searcher = new Searcher( $conn, 0, 0, $config, [], $wgUser );
		$db = wfGetDB( DB_REPLICA );

		do {
			// $table, $vars, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
			$res = $db->select( 'page', [ 'page_namespace', 'page_title' ],
				[ 'page_title > ' . $db->addQuotes( $start ) ] , __METHOD__,
				[ 'ORDER BY' => 'page_title', 'LIMIT' => $this->getBatchSize() ] );

			foreach ( $res as $row ) {
				$numArticles++;
				$start = $row->page_title;
				$title = Title::makeTitleSafe( $row->page_namespace, $row->page_title );
				if ($title === null) {
					$this->output( "unable to create title object from " .
						"{$row->page_namespace}: {$row->page_title}\n" );
					continue;
				}
				$docId = $config->makeId( $title->getArticleID() );
				$esSources = $searcher->get( [ $docId ], true );

				// We erroneously relied on if ( !$esSources->isOK() )
				// until it was discovered that
				// the bad articles were already marked 'OK'.
				if ( !count($esSources->value) ) {
					$numBad++;
					if ( $this->mVerbose ) {
						$this->output( $title->getText() . "\n" );
					}
					if ( !$this->mNope ) {
						$page = new WikiPage( $title );
						$page->doEditContent( $page->getContent(), 'This changes nothing', EDIT_UPDATE, false, $wgUser );
						$this->output( $title->getText() . " fixed\n" );
					}
				}
			}
		} while ( $res->numRows() );

		$this->output( "Found $numBad hidden articles out of $numArticles.\n\n" );
	}
}

$maintClass = PurgeUnindexedPages::class;
require_once RUN_MAINTENANCE_IF_MAIN;