<?php
/**
 * Daily job: delete old rows, pick up stuck messages.
 *
 * @package Smsportal
 */

namespace Smsportal;

defined( 'ABSPATH' ) || exit;

/**
 * Once a day (WP-Cron): sent SMS, replies and the connection log older than 90 days are deleted.
 * The block list is kept: it stops SMS to people who opted out. Once an hour: messages stuck in the
 * queue are scheduled again.
 */
class Retention {

	const HOOK        = 'smsportal_daily';
	const HOURLY_HOOK = 'smsportal_hourly';
	const DAYS  = 90;
	const BATCH = 1000;

	/**
	 * Register the job and make sure it is scheduled.
	 *
	 * @return void
	 */
	public static function register(): void {
		add_action( self::HOOK, array( self::class, 'run' ) );
		add_action( self::HOURLY_HOOK, array( Queue::class, 'recover_stuck' ) );
		// Activation schedules the jobs; init re-adds them after an update or a lost cron entry.
		add_action( 'init', array( self::class, 'schedule' ) );
	}

	/**
	 * Schedule the daily and hourly jobs unless they already are.
	 *
	 * @return void
	 */
	public static function schedule(): void {
		if ( false === wp_next_scheduled( self::HOOK ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, 'daily', self::HOOK );
		}
		if ( false === wp_next_scheduled( self::HOURLY_HOOK ) ) {
			wp_schedule_event( time() + Queue::STUCK_AFTER, 'hourly', self::HOURLY_HOOK );
		}
	}

	/**
	 * Remove both jobs (plugin deactivated).
	 *
	 * @return void
	 */
	public static function unschedule(): void {
		wp_clear_scheduled_hook( self::HOOK );
		wp_clear_scheduled_hook( self::HOURLY_HOOK );
	}

	/**
	 * Daily job: delete old rows.
	 *
	 * @return void
	 */
	public static function run(): void {
		self::purge();
	}

	/**
	 * Delete rows older than DAYS, in batches so a big table is not locked for long.
	 *
	 * @return void
	 */
	public static function purge(): void {
		global $wpdb;
		$cutoff = gmdate( 'Y-m-d H:i:s', time() - self::DAYS * DAY_IN_SECONDS );

		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- the plugin's own tables.
		self::in_batches(
			static function () use ( $wpdb, $cutoff ) {
				return $wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->prefix}smsportal_messages WHERE created_at < %s LIMIT %d", $cutoff, self::BATCH ) );
			}
		);
		self::in_batches(
			static function () use ( $wpdb, $cutoff ) {
				return $wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->prefix}smsportal_replies WHERE received_at < %s LIMIT %d", $cutoff, self::BATCH ) );
			}
		);
		self::in_batches(
			static function () use ( $wpdb, $cutoff ) {
				return $wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->prefix}smsportal_connection_log WHERE created_at < %s LIMIT %d", $cutoff, self::BATCH ) );
			}
		);
		// phpcs:enable
	}

	/**
	 * Repeat a DELETE … LIMIT BATCH until it deletes fewer rows than a batch (or fails).
	 *
	 * @param callable $delete Runs one batch, returns the rows deleted or false.
	 * @return void
	 */
	private static function in_batches( callable $delete ): void {
		do {
			$deleted = $delete();
		} while ( false !== $deleted && (int) $deleted >= self::BATCH );
	}
}