<?php
/**
 * Background job health.
 *
 * @package AdminPowerups
 */

namespace SmartWP\AdminPowerups\Support;

use ActionScheduler;
use ActionScheduler_Store;

defined( 'ABSPATH' ) || exit;

/**
 * Checks whether our Action Scheduler jobs (group `apwc`, `Jobs::GROUP`) actually run.
 *
 * Runs the check. Callers normally read the cached copy from SystemStatus instead.
 *
 * @since 1.0.0
 */
final class Health {

	/**
	 * A job counts as overdue this long after its due time.
	 */
	const GRACE = 10 * MINUTE_IN_SECONDS;

	/**
	 * Failed jobs are counted over this window.
	 */
	const FAILED_WINDOW = 7 * DAY_IN_SECONDS;

	/**
	 * Per-request cache.
	 *
	 * @var array{status: string, label: string, message: string, overdue: int, failed: int, pending: int, cron_disabled: bool}|null
	 */
	private static $cache = null;

	/**
	 * Run the background job check (once per request).
	 *
	 * @since 1.0.0
	 * @return array{status: string, label: string, message: string, overdue: int, failed: int, pending: int, cron_disabled: bool}
	 *   status: good | recommended | critical.
	 */
	public static function check() {
		if ( null !== self::$cache ) {
			return self::$cache;
		}

		/**
		 * Filter whether WP-Cron counts as off. Return false when a server cron runs WordPress's cron
		 * (common with DISABLE_WP_CRON), so the check only warns about real delays.
		 *
		 * @since 1.0.0
		 * @param bool $disabled Whether DISABLE_WP_CRON is set.
		 */
		$cron_disabled = (bool) apply_filters( 'apwc_wp_cron_disabled', defined( 'DISABLE_WP_CRON' ) && DISABLE_WP_CRON );
		$overdue       = self::count( ActionScheduler_Store::STATUS_PENDING, time() - self::GRACE, '<=' );
		$pending       = self::count( ActionScheduler_Store::STATUS_PENDING );
		$failed        = self::count( ActionScheduler_Store::STATUS_FAILED, time() - self::FAILED_WINDOW, '>=' );

		if ( $overdue > 0 ) {
			$status = 'critical';
			/* translators: %d: number of jobs. */
			$label   = sprintf( _n( '%d job overdue', '%d jobs overdue', $overdue, 'admin-powerups-for-woocommerce' ), $overdue );
			$message = $cron_disabled
				? __( 'Scheduled jobs are not running. WP-Cron is turned off on this site, so your host must run a server cron every minute.', 'admin-powerups-for-woocommerce' )
				: __( 'Scheduled jobs are running late. This usually means the site gets few visits, or WP-Cron is blocked. Ask your host to run a server cron every minute.', 'admin-powerups-for-woocommerce' );
		} elseif ( $cron_disabled ) {
			$status  = 'recommended';
			$label   = __( 'WP-Cron off', 'admin-powerups-for-woocommerce' );
			$message = __( 'WP-Cron is turned off. Jobs only run if your host runs a server cron. Nothing is late right now.', 'admin-powerups-for-woocommerce' );
		} else {
			$status  = 'good';
			$label   = __( 'Running', 'admin-powerups-for-woocommerce' );
			$message = __( 'Scheduled jobs are running on time.', 'admin-powerups-for-woocommerce' );
		}

		$result = array(
			'status'        => $status,
			'label'         => $label,
			'message'       => $message,
			'overdue'       => $overdue,
			'failed'        => $failed,
			'pending'       => $pending,
			'cron_disabled' => $cron_disabled,
		);

		/**
		 * Filter the background job health result.
		 *
		 * @since 1.0.0
		 * @param array $result Result.
		 */
		self::$cache = (array) apply_filters( 'apwc_background_jobs_health', $result );
		return self::$cache;
	}

	/**
	 * Warning text for "wait" settings, or '' when jobs are healthy.
	 *
	 * @since 1.0.0
	 * @return string
	 */
	public static function wait_warning() {
		$jobs = SystemStatus::get()['jobs'];
		return 'good' === $jobs['status'] ? '' : $jobs['message'];
	}

	/**
	 * Forget this request's result.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function flush() {
		self::$cache = null;
	}

	/**
	 * Count our jobs in one query.
	 *
	 * @since 1.0.0
	 * @param string   $status  Action Scheduler status.
	 * @param int|null $date    Unix time to compare the scheduled date with.
	 * @param string   $compare Comparison operator.
	 * @return int
	 */
	private static function count( $status, $date = null, $compare = '<=' ) {
		if ( ! class_exists( ActionScheduler::class ) || ! ActionScheduler::is_initialized() ) {
			return 0;
		}
		$query = array(
			'group'  => Jobs::GROUP,
			'status' => $status,
		);
		if ( null !== $date ) {
			$query['date']         = as_get_datetime_object( $date ); // The store expects a DateTime (UTC).
			$query['date_compare'] = $compare;
		}
		return (int) ActionScheduler::store()->query_actions( $query, 'count' );
	}
}