<?php
/**
 * Move revision's text to external storage
 *
 * 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 ExternalStorage
 */

// NO_AUTOLOAD -- file scope code

use MediaWiki\MediaWikiServices;

define( 'REPORTING_INTERVAL', 1 );

if ( !defined( 'MEDIAWIKI' ) ) {
	$optionsWithArgs = [ 'e', 's' ];
	require_once __DIR__ . '/../CommandLineInc.php';
	require_once 'resolveStubs.php';

	$fname = 'moveToExternal';

	if ( !isset( $args[1] ) ) {
		print "Usage: php moveToExternal.php [-s <startid>] [-e <endid>] <type> <location>\n";
		exit;
	}

	$type = $args[0]; // e.g. "DB" or "mwstore"
	$location = $args[1]; // e.g. "cluster12" or "global-swift"
	$dbw = wfGetDB( DB_PRIMARY );

	$maxID = (int)( $options['e'] ?? $dbw->selectField( 'text', 'MAX(old_id)', '', $fname ) );
	$minID = (int)( $options['s'] ?? 1 );

	moveToExternal( $type, $location, $maxID, $minID );
}

function moveToExternal( $type, $location, $maxID, $minID = 1 ) {
	$fname = 'moveToExternal';
	$dbw = wfGetDB( DB_PRIMARY );
	$dbr = wfGetDB( DB_REPLICA );

	$count = $maxID - $minID + 1;
	$blockSize = 1000;
	$numBlocks = ceil( $count / $blockSize );
	print "Moving text rows from $minID to $maxID to external storage\n";

	$esFactory = MediaWikiServices::getInstance()->getExternalStoreFactory();
	$lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
	$extStore = $esFactory->getStore( $type );
	$numMoved = 0;

	for ( $block = 0; $block < $numBlocks; $block++ ) {
		$blockStart = $block * $blockSize + $minID;
		$blockEnd = $blockStart + $blockSize - 1;

		if ( !( $block % REPORTING_INTERVAL ) ) {
			print "oldid=$blockStart, moved=$numMoved\n";
			$lbFactory->waitForReplication();
		}

		$res = $dbr->select( 'text', [ 'old_id', 'old_flags', 'old_text' ],
			[
				"old_id BETWEEN $blockStart AND $blockEnd",
				'old_flags NOT ' . $dbr->buildLike( $dbr->anyString(), 'external', $dbr->anyString() ),
			], $fname
		);
		foreach ( $res as $row ) {
			# Resolve stubs
			$text = $row->old_text;
			$id = $row->old_id;
			if ( $row->old_flags === '' ) {
				$flags = 'external';
			} else {
				$flags = "{$row->old_flags},external";
			}

			if ( strpos( $flags, 'object' ) !== false ) {
				$obj = unserialize( $text );
				$className = strtolower( get_class( $obj ) );
				if ( $className == 'historyblobstub' ) {
					# resolveStub( $id, $row->old_text, $row->old_flags );
					# $numStubs++;
					continue;
				} elseif ( $className == 'historyblobcurstub' ) {
					$text = gzdeflate( $obj->getText() );
					$flags = 'utf-8,gzip,external';
				} elseif ( $className == 'concatenatedgziphistoryblob' ) {
					// Do nothing
				} else {
					print "Warning: unrecognised object class \"$className\"\n";
					continue;
				}
			} else {
				$className = false;
			}

			if ( strlen( $text ) < 100 && $className === false ) {
				// Don't move tiny revisions
				continue;
			}

			# print "Storing "  . strlen( $text ) . " bytes to $url\n";
			# print "old_id=$id\n";

			$url = $extStore->store( $location, $text );
			if ( !$url ) {
				print "Error writing to external storage\n";
				exit;
			}
			$dbw->update( 'text',
				[ 'old_flags' => $flags, 'old_text' => $url ],
				[ 'old_id' => $id ], $fname );
			$numMoved++;
		}
	}
}
