<?php
/**
 * Rebuild recent changes from scratch.  This takes several hours,
 * depending on the database size and server configuration.
 *
 * 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
 * @todo Document
 */

require_once __DIR__ . '/Maintenance.php';

/**
 * Maintenance script that rebuilds recent changes from scratch.
 *
 * @ingroup Maintenance
 */
class RebuildRecentchanges extends Maintenance {
	/** @var integer UNIX timestamp */
	private $cutoffFrom;
	/** @var integer UNIX timestamp */
	private $cutoffTo;

	public function __construct() {
		parent::__construct();
		$this->addDescription( 'Rebuild recent changes' );

		$this->addOption(
			'from',
			"Only rebuild rows in requested time range (in YYYYMMDDHHMMSS format)",
			false,
			true
		);
		$this->addOption(
			'to',
			"Only rebuild rows in requested time range (in YYYYMMDDHHMMSS format)",
			false,
			true
		);
		$this->setBatchSize( 200 );
	}

	public function execute() {
		if (
			( $this->hasOption( 'from' ) && !$this->hasOption( 'to' ) ) ||
			( !$this->hasOption( 'from' ) && $this->hasOption( 'to' ) )
		) {
			$this->error( "Both 'from' and 'to' must be given, or neither", 1 );
		}

		$this->rebuildRecentChangesTablePass1();
		$this->rebuildRecentChangesTablePass2();
		$this->rebuildRecentChangesTablePass3();
		$this->rebuildRecentChangesTablePass4();
		$this->rebuildRecentChangesTablePass5();
		if ( !( $this->hasOption( 'from' ) && $this->hasOption( 'to' ) ) ) {
			$this->purgeFeeds();
		}
		$this->output( "Done.\n" );
	}

	/**
	 * Rebuild pass 1: Insert `recentchanges` entries for page revisions.
	 */
	private function rebuildRecentChangesTablePass1() {
		$dbw = $this->getDB( DB_MASTER );

		if ( $this->hasOption( 'from' ) && $this->hasOption( 'to' ) ) {
			$this->cutoffFrom = wfTimestamp( TS_UNIX, $this->getOption( 'from' ) );
			$this->cutoffTo = wfTimestamp( TS_UNIX, $this->getOption( 'to' ) );

			$sec = $this->cutoffTo - $this->cutoffFrom;
			$days = $sec / 24 / 3600;
			$this->output( "Rebuilding range of $sec seconds ($days days)\n" );
		} else {
			global $wgRCMaxAge;

			$days = $wgRCMaxAge / 24 / 3600;
			$this->output( "Rebuilding \$wgRCMaxAge=$wgRCMaxAge seconds ($days days)\n" );

			$this->cutoffFrom = time() - $wgRCMaxAge;
			$this->cutoffTo = time();
		}

		$this->output( "Clearing recentchanges table for time range...\n" );
		$rcids = $dbw->selectFieldValues(
			'recentchanges',
			'rc_id',
			[
				'rc_timestamp > ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffFrom ) ),
				'rc_timestamp < ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffTo ) )
			]
		);
		foreach ( array_chunk( $rcids, $this->mBatchSize ) as $rcidBatch ) {
			$dbw->delete( 'recentchanges', [ 'rc_id' => $rcidBatch ], __METHOD__ );
			wfGetLBFactory()->waitForReplication();
		}

		$this->output( "Loading from page and revision tables...\n" );
		$res = $dbw->select(
			[ 'page', 'revision' ],
			[
				'rev_timestamp',
				'rev_user',
				'rev_user_text',
				'rev_comment',
				'rev_minor_edit',
				'rev_id',
				'rev_deleted',
				'page_namespace',
				'page_title',
				'page_is_new',
				'page_id'
			],
			[
				'rev_timestamp > ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffFrom ) ),
				'rev_timestamp < ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffTo ) ),
				'rev_page=page_id'
			],
			__METHOD__,
			[ 'ORDER BY' => 'rev_timestamp DESC' ]
		);

		$this->output( "Inserting from page and revision tables...\n" );
		$inserted = 0;
		foreach ( $res as $row ) {
			$dbw->insert(
				'recentchanges',
				[
					'rc_timestamp' => $row->rev_timestamp,
					'rc_user' => $row->rev_user,
					'rc_user_text' => $row->rev_user_text,
					'rc_namespace' => $row->page_namespace,
					'rc_title' => $row->page_title,
					'rc_comment' => $row->rev_comment,
					'rc_minor' => $row->rev_minor_edit,
					'rc_bot' => 0,
					'rc_new' => $row->page_is_new,
					'rc_cur_id' => $row->page_id,
					'rc_this_oldid' => $row->rev_id,
					'rc_last_oldid' => 0, // is this ok?
					'rc_type' => $row->page_is_new ? RC_NEW : RC_EDIT,
					'rc_source' => $row->page_is_new
						? $dbw->addQuotes( RecentChange::SRC_NEW )
						: $dbw->addQuotes( RecentChange::SRC_EDIT )
					,
					'rc_deleted' => $row->rev_deleted
				],
				__METHOD__
			);
			if ( ( ++$inserted % $this->mBatchSize ) == 0 ) {
				wfGetLBFactory()->waitForReplication();
			}
		}
	}

	/**
	 * Rebuild pass 2: Enhance entries for page revisions with references to the previous revision
	 * (rc_last_oldid, rc_new etc.) and size differences (rc_old_len, rc_new_len).
	 */
	private function rebuildRecentChangesTablePass2() {
		$dbw = $this->getDB( DB_MASTER );

		$this->output( "Updating links and size differences...\n" );

		# Fill in the rc_last_oldid field, which points to the previous edit
		$res = $dbw->select(
			'recentchanges',
			[ 'rc_cur_id', 'rc_this_oldid', 'rc_timestamp' ],
			[
				"rc_timestamp > " . $dbw->addQuotes( $dbw->timestamp( $this->cutoffFrom ) ),
				"rc_timestamp < " . $dbw->addQuotes( $dbw->timestamp( $this->cutoffTo ) )
			],
			__METHOD__,
			[ 'ORDER BY' => 'rc_cur_id,rc_timestamp' ]
		);

		$lastCurId = 0;
		$lastOldId = 0;
		$lastSize = null;
		$updated = 0;
		foreach ( $res as $obj ) {
			$new = 0;

			if ( $obj->rc_cur_id != $lastCurId ) {
				# Switch! Look up the previous last edit, if any
				$lastCurId = intval( $obj->rc_cur_id );
				$emit = $obj->rc_timestamp;

				$row = $dbw->selectRow(
					'revision',
					[ 'rev_id', 'rev_len' ],
					[ 'rev_page' => $lastCurId, "rev_timestamp < " . $dbw->addQuotes( $emit ) ],
					__METHOD__,
					[ 'ORDER BY' => 'rev_timestamp DESC' ]
				);
				if ( $row ) {
					$lastOldId = intval( $row->rev_id );
					# Grab the last text size if available
					$lastSize = !is_null( $row->rev_len ) ? intval( $row->rev_len ) : null;
				} else {
					# No previous edit
					$lastOldId = 0;
					$lastSize = null;
					$new = 1; // probably true
				}
			}

			if ( $lastCurId == 0 ) {
				$this->output( "Uhhh, something wrong? No curid\n" );
			} else {
				# Grab the entry's text size
				$size = (int)$dbw->selectField(
					'revision',
					'rev_len',
					[ 'rev_id' => $obj->rc_this_oldid ],
					__METHOD__
				);

				$dbw->update(
					'recentchanges',
					[
						'rc_last_oldid' => $lastOldId,
						'rc_new' => $new,
						'rc_type' => $new ? RC_NEW : RC_EDIT,
						'rc_source' => $new === 1
							? $dbw->addQuotes( RecentChange::SRC_NEW )
							: $dbw->addQuotes( RecentChange::SRC_EDIT ),
						'rc_old_len' => $lastSize,
						'rc_new_len' => $size,
					],
					[
						'rc_cur_id' => $lastCurId,
						'rc_this_oldid' => $obj->rc_this_oldid,
						'rc_timestamp' => $obj->rc_timestamp // index usage
					],
					__METHOD__
				);

				$lastOldId = intval( $obj->rc_this_oldid );
				$lastSize = $size;

				if ( ( ++$updated % $this->mBatchSize ) == 0 ) {
					wfGetLBFactory()->waitForReplication();
				}
			}
		}
	}

	/**
	 * Rebuild pass 3: Insert `recentchanges` entries for action logs.
	 */
	private function rebuildRecentChangesTablePass3() {
		global $wgLogTypes, $wgLogRestrictions;

		$dbw = $this->getDB( DB_MASTER );

		$this->output( "Loading from user, page, and logging tables...\n" );

		$res = $dbw->select(
			[ 'user', 'logging', 'page' ],
			[
				'log_timestamp',
				'log_user',
				'user_name',
				'log_namespace',
				'log_title',
				'log_comment',
				'page_id',
				'log_type',
				'log_action',
				'log_id',
				'log_params',
				'log_deleted'
			],
			[
				'log_timestamp > ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffFrom ) ),
				'log_timestamp < ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffTo ) ),
				'log_user=user_id',
				// Some logs don't go in RC since they are private.
				// @FIXME: core/extensions also have spammy logs that don't go in RC.
				'log_type' => array_diff( $wgLogTypes, array_keys( $wgLogRestrictions ) ),
			],
			__METHOD__,
			[ 'ORDER BY' => 'log_timestamp DESC' ],
			[
				'page' =>
					[ 'LEFT JOIN', [ 'log_namespace=page_namespace', 'log_title=page_title' ] ]
			]
		);

		$field = $dbw->fieldInfo( 'recentchanges', 'rc_cur_id' );

		$inserted = 0;
		foreach ( $res as $row ) {
			$dbw->insert(
				'recentchanges',
				[
					'rc_timestamp' => $row->log_timestamp,
					'rc_user' => $row->log_user,
					'rc_user_text' => $row->user_name,
					'rc_namespace' => $row->log_namespace,
					'rc_title' => $row->log_title,
					'rc_comment' => $row->log_comment,
					'rc_minor' => 0,
					'rc_bot' => 0,
					'rc_patrolled' => 1,
					'rc_new' => 0,
					'rc_this_oldid' => 0,
					'rc_last_oldid' => 0,
					'rc_type' => RC_LOG,
					'rc_source' => $dbw->addQuotes( RecentChange::SRC_LOG ),
					'rc_cur_id' => $field->isNullable()
						? $row->page_id
						: (int)$row->page_id, // NULL => 0,
					'rc_log_type' => $row->log_type,
					'rc_log_action' => $row->log_action,
					'rc_logid' => $row->log_id,
					'rc_params' => $row->log_params,
					'rc_deleted' => $row->log_deleted
				],
				__METHOD__
			);

			if ( ( ++$inserted % $this->mBatchSize ) == 0 ) {
				wfGetLBFactory()->waitForReplication();
			}
		}
	}

	/**
	 * Rebuild pass 4: Mark bot and autopatrolled entries.
	 */
	private function rebuildRecentChangesTablePass4() {
		global $wgUseRCPatrol, $wgMiserMode;

		$dbw = $this->getDB( DB_MASTER );

		list( $recentchanges, $usergroups, $user ) =
			$dbw->tableNamesN( 'recentchanges', 'user_groups', 'user' );

		# @FIXME: recognize other bot account groups (not the same as users with 'bot' rights)
		# @NOTE: users with 'bot' rights choose when edits are bot edits or not. That information
		# may be lost at this point (aside from joining on the patrol log table entries).
		$botgroups = [ 'bot' ];
		$autopatrolgroups = $wgUseRCPatrol ? User::getGroupsWithPermission( 'autopatrol' ) : [];

		# Flag our recent bot edits
		if ( $botgroups ) {
			$botwhere = $dbw->makeList( $botgroups );

			$this->output( "Flagging bot account edits...\n" );

			# Find all users that are bots
			$sql = "SELECT DISTINCT user_name FROM $usergroups, $user " .
				"WHERE ug_group IN($botwhere) AND user_id = ug_user";
			$res = $dbw->query( $sql, __METHOD__ );

			$botusers = [];
			foreach ( $res as $obj ) {
				$botusers[] = $obj->user_name;
			}

			# Fill in the rc_bot field
			if ( $botusers ) {
				$rcids = $dbw->selectFieldValues(
					'recentchanges',
					'rc_id',
					[
						'rc_user_text' => $botusers,
						"rc_timestamp > " . $dbw->addQuotes( $dbw->timestamp( $this->cutoffFrom ) ),
						"rc_timestamp < " . $dbw->addQuotes( $dbw->timestamp( $this->cutoffTo ) )
					],
					__METHOD__
				);

				foreach ( array_chunk( $rcids, $this->mBatchSize ) as $rcidBatch ) {
					$dbw->update(
						'recentchanges',
						[ 'rc_bot' => 1 ],
						[ 'rc_id' => $rcidBatch ],
						__METHOD__
					);
					wfGetLBFactory()->waitForReplication();
				}
			}
		}

		# Flag our recent autopatrolled edits
		if ( !$wgMiserMode && $autopatrolgroups ) {
			$patrolwhere = $dbw->makeList( $autopatrolgroups );
			$patrolusers = [];

			$this->output( "Flagging auto-patrolled edits...\n" );

			# Find all users in RC with autopatrol rights
			$sql = "SELECT DISTINCT user_name FROM $usergroups, $user " .
				"WHERE ug_group IN($patrolwhere) AND user_id = ug_user";
			$res = $dbw->query( $sql, __METHOD__ );

			foreach ( $res as $obj ) {
				$patrolusers[] = $dbw->addQuotes( $obj->user_name );
			}

			# Fill in the rc_patrolled field
			if ( $patrolusers ) {
				$patrolwhere = implode( ',', $patrolusers );
				$sql2 = "UPDATE $recentchanges SET rc_patrolled=1 " .
					"WHERE rc_user_text IN($patrolwhere) " .
					"AND rc_timestamp > " . $dbw->addQuotes( $dbw->timestamp( $this->cutoffFrom ) ) . ' ' .
					"AND rc_timestamp < " . $dbw->addQuotes( $dbw->timestamp( $this->cutoffTo ) );
				$dbw->query( $sql2 );
			}
		}
	}

	/**
	 * Rebuild pass 5: Delete duplicate entries where we generate both a page revision and a log entry
	 * for a single action (upload only, at the moment, but potentially also move, protect, ...).
	 */
	private function rebuildRecentChangesTablePass5() {
		$dbw = wfGetDB( DB_MASTER );

		$this->output( "Removing duplicate revision and logging entries...\n" );

		$res = $dbw->select(
			[ 'logging', 'log_search' ],
			[ 'ls_value', 'ls_log_id' ],
			[
				'ls_log_id = log_id',
				'ls_field' => 'associated_rev_id',
				'log_type' => 'upload',
				'log_timestamp > ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffFrom ) ),
				'log_timestamp < ' . $dbw->addQuotes( $dbw->timestamp( $this->cutoffTo ) ),
			],
			__METHOD__
		);

		$updates = 0;
		foreach ( $res as $obj ) {
			$rev_id = $obj->ls_value;
			$log_id = $obj->ls_log_id;

			// Mark the logging row as having an associated rev id
			$dbw->update(
				'recentchanges',
				/*SET*/ [ 'rc_this_oldid' => $rev_id ],
				/*WHERE*/ [ 'rc_logid' => $log_id ],
				__METHOD__
			);

			// Delete the revision row
			$dbw->delete(
				'recentchanges',
				/*WHERE*/ [ 'rc_this_oldid' => $rev_id, 'rc_logid' => 0 ],
				__METHOD__
			);

			if ( ( ++$updates % $this->mBatchSize ) == 0 ) {
				wfGetLBFactory()->waitForReplication();
			}
		}
	}

	/**
	 * Purge cached feeds in $messageMemc
	 */
	private function purgeFeeds() {
		global $wgFeedClasses, $messageMemc;

		$this->output( "Deleting feed timestamps.\n" );

		foreach ( $wgFeedClasses as $feed => $className ) {
			$messageMemc->delete( wfMemcKey( 'rcfeed', $feed, 'timestamp' ) ); # Good enough for now.
		}
	}
}

$maintClass = "RebuildRecentchanges";
require_once RUN_MAINTENANCE_IF_MAIN;
