<?php
/**
 * 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
 */

namespace MediaWiki\Linter;

use WANObjectCache;
use Wikimedia\Rdbms\Database as MWDatabase;

/**
 * Lookup to find and cache the total amount of
 * lint errors in each category
 */
class TotalsLookup {

	/**
	 * @var WANObjectCache
	 */
	private $cache;

	/**
	 * @var CategoryManager
	 */
	private $catManager;

	/**
	 * @param CategoryManager $catManager
	 * @param WANObjectCache $cache
	 */
	public function __construct( CategoryManager $catManager, WANObjectCache $cache ) {
		$this->cache = $cache;
		$this->catManager = $catManager;
	}

	/**
	 * @param string $cat
	 * @return string
	 */
	private function makeKey( $cat ) {
		return $this->cache->makeKey( 'linter', 'total', $cat );
	}

	/**
	 * Get the totals for every category in the database
	 *
	 * @return array
	 */
	public function getTotals() {
		$cats = $this->catManager->getVisibleCategories();
		$fetchedTotals = false;
		$totals = [];
		foreach ( $cats as $cat ) {
			$totals[$cat] = $this->cache->getWithSetCallback(
				$this->makeKey( $cat ),
				WANObjectCache::TTL_INDEFINITE,
				static function ( $oldValue, &$ttl, &$setOpts, $oldAsOf ) use ( $cat, &$fetchedTotals ) {
					$setOpts += MWDatabase::getCacheSetOptions(
						Database::getDBConnectionRef( DB_REPLICA )
					);
					if ( $fetchedTotals === false ) {
						$fetchedTotals = ( new Database( 0 ) )->getTotals();
					}

					return $fetchedTotals[$cat];
				},
				[
					'checkKeys' => [
						$this->cache->makeKey( 'linter', 'totals' ),
						$this->makeKey( $cat ),
					],
					'lockTSE' => 30,
				]
			);
		}

		return $totals;
	}

	/**
	 * Have a single category be recalculated
	 *
	 * @param string $cat category name
	 */
	public function touchCategoryCache( $cat ) {
		$this->cache->touchCheckKey( $this->makeKey( $cat ) );
	}

	/**
	 * Have all categories be recalculated
	 */
	public function touchAllCategoriesCache() {
		$this->cache->touchCheckKey( $this->cache->makeKey( 'linter', 'totals' ) );
	}
}