<?php
namespace QWSpeedCache\Cache;

defined( 'ABSPATH' ) || exit;

/**
 * Cron job: delete expired page-cache HTML/meta by lifespan.
 */
class StaleCleanup {

	const CRON = 'qwsc_cache_stale_cleanup';

	public function __construct() {
		add_action( self::CRON, array( $this, 'run' ) );
		add_action( 'init', array( $this, 'maybe_schedule' ), 40 );
		add_action( 'update_option_qwsc_settings', array( $this, 'on_settings' ), 30, 2 );
	}

	public function maybe_schedule() {
		$s = \QWSpeedCache\Plugin::instance()->get_all_settings();
		if ( empty( $s['cache_stale_cleanup'] ) && empty( $s['page_cache_enabled'] ) && empty( $s['cache_enabled'] ) ) {
			$this->unschedule();
			return;
		}
		// Always schedule when page cache is on so lifespan is enforced offline.
		$need = ! empty( $s['page_cache_enabled'] ) || ! empty( $s['cache_enabled'] ) || ! empty( $s['cache_stale_cleanup'] );
		if ( ! $need ) {
			$this->unschedule();
			return;
		}
		if ( ! wp_next_scheduled( self::CRON ) ) {
			wp_schedule_event( time() + 300, 'hourly', self::CRON );
		}
	}

	/**
	 * @param mixed $old Old.
	 * @param mixed $new New.
	 */
	public function on_settings( $old, $new ) {
		$this->maybe_schedule();
	}

	public function unschedule() {
		$ts = wp_next_scheduled( self::CRON );
		while ( $ts ) {
			wp_unschedule_event( $ts, self::CRON );
			$ts = wp_next_scheduled( self::CRON );
		}
	}

	/**
	 * Delete expired .html/.meta under cache dir.
	 *
	 * @param string $cache_dir Directory.
	 * @param int    $hours     Lifespan hours (0 = only remove ancient > 30d).
	 * @return int Files removed.
	 */
	public static function purge_expired_files( $cache_dir, $hours ) {
		$cache_dir = (string) $cache_dir;
		if ( '' === $cache_dir || ! is_dir( $cache_dir ) ) {
			return 0;
		}
		$hours = (int) $hours;
		$ttl   = $hours > 0 ? $hours * ( defined( '\HOUR_IN_SECONDS' ) ? \HOUR_IN_SECONDS : 3600 ) : ( 30 * \DAY_IN_SECONDS );
		if ( ! defined( '\DAY_IN_SECONDS' ) && $hours <= 0 ) {
			$ttl = 30 * 86400;
		}
		$now     = time();
		$removed = 0;
		$it      = new \RecursiveIteratorIterator(
			new \RecursiveDirectoryIterator( $cache_dir, \FilesystemIterator::SKIP_DOTS )
		);
		foreach ( $it as $file ) {
			if ( ! $file->isFile() ) {
				continue;
			}
			$name = $file->getFilename();
			if ( ! preg_match( '/\.(html|meta\.json)$/', $name ) ) {
				continue;
			}
			$mtime = (int) $file->getMTime();
			if ( ( $now - $mtime ) > $ttl ) {
				// phpcs:ignore WordPress.WP.AlternativeFunctions.unlink_unlink -- stale cache file cleanup.
				$path = $file->getPathname();
				if ( is_file( $path ) && wp_delete_file( $path ) ) {
					++$removed;
				}
			}
		}
		return $removed;
	}

	public function run() {
		$s        = \QWSpeedCache\Plugin::instance()->get_all_settings();
		$hours    = (int) ( $s['cache_lifespan'] ?? 10 );
		$cache_dir = defined( 'QWSC_CACHE_DIR' ) ? QWSC_CACHE_DIR : ( WP_CONTENT_DIR . '/cache/qw-speed-cache/' );
		$n         = self::purge_expired_files( $cache_dir, $hours );
		if ( class_exists( '\QWSpeedCache\Stats\Logger' ) && $n > 0 ) {
			\QWSpeedCache\Stats\Logger::log( 'cache', 'stale_cleanup removed ' . $n );
		}
		// Also temps/locks.
		if ( class_exists( '\QWSpeedCache\Cache\Engine' ) ) {
			$engine = new Engine();
			$engine->cleanup_stale_temps();
		}
	}
}