<?php
/**
 * Scheduled backups through WP-Cron, run in the same resumable slices as manual ones.
 *
 * @package Shiftbox
 */

// phpcs:disable WordPress.WP.AlternativeFunctions, WordPress.PHP.NoSilencedErrors.Discouraged

defined( 'ABSPATH' ) || exit;

/**
 * Scheduler.
 */
class Shiftbox_Scheduler {

	const HOOK_START = 'shiftbox_scheduled_backup';
	const HOOK_RUN   = 'shiftbox_run_job';

	/**
	 * Registers hooks.
	 *
	 * @return void
	 */
	public static function init() {
		add_action( self::HOOK_START, array( __CLASS__, 'start' ) );
		add_action( self::HOOK_RUN, array( __CLASS__, 'run' ), 10, 2 );
	}

	/**
	 * Re-creates the recurring event.
	 *
	 * @param string $schedule off|daily|weekly.
	 * @return void
	 */
	public static function reschedule( $schedule ) {
		wp_clear_scheduled_hook( self::HOOK_START );
		if ( in_array( $schedule, array( 'daily', 'weekly' ), true ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, $schedule, self::HOOK_START );
		}
	}

	/**
	 * Removes all events (on deactivation).
	 *
	 * @return void
	 */
	public static function unschedule_all() {
		wp_clear_scheduled_hook( self::HOOK_START );
		wp_clear_scheduled_hook( self::HOOK_RUN );
	}

	/**
	 * Starts a scheduled backup.
	 *
	 * @return void
	 */
	public static function start() {
		Shiftbox_Job::cleanup_stale();
		$job = Shiftbox_Runner::start_export(
			array(
				'tag'          => 'scheduled',
				'no_revisions' => true,
				'no_spam'      => true,
			)
		);
		if ( ! is_wp_error( $job ) ) {
			wp_schedule_single_event( time(), self::HOOK_RUN, array( $job->id, 1 ) );
		}
	}

	/**
	 * Runs one slice, then queues the next one.
	 *
	 * @param string $id Job id.
	 * @param int    $n  Slice counter (keeps events unique).
	 * @return void
	 */
	public static function run( $id, $n = 1 ) {
		$status = Shiftbox_Runner::tick( $id );
		if ( empty( $status['done'] ) && empty( $status['error'] ) && empty( $status['gone'] ) && $n < 5000 ) {
			wp_schedule_single_event( time() + ( empty( $status['busy'] ) ? 1 : 15 ), self::HOOK_RUN, array( $id, $n + 1 ) );
		}
	}

	/**
	 * Keeps only the newest scheduled backups.
	 *
	 * @return void
	 */
	public static function apply_retention() {
		$keep = (int) Shiftbox_Settings::get( 'keep' );
		$n    = 0;
		foreach ( Shiftbox_Storage::list_backups() as $b ) {
			if ( false === strpos( $b['name'], '-scheduled-' ) ) {
				continue;
			}
			++$n;
			if ( $n > $keep ) {
				@unlink( Shiftbox_Storage::dir() . '/' . $b['name'] );
			}
		}
	}
}