<?php
/**
 * Background housekeeping.
 *
 * @package VibrateSMS
 */

namespace VibrateSMS;

defined( 'ABSPATH' ) || exit;

/**
 * Every ten minutes: recover batches a dead worker left behind, pull
 * delivery receipts for recent sends, and once a day prune the log.
 */
final class Maintenance {

	const HOOK         = 'vibrate_sms_maintenance';
	const SCHEDULE     = 'vibrate_sms_ten_minutes';
	const PURGE_OPTION = 'vibrate_sms_last_purge';

	const RUNS_PER_TICK = 25;
	const TIME_BUDGET   = 25;

	/** A batch claimed this long ago without an answer is presumed orphaned. */
	const STALE_SENDING = 10 * MINUTE_IN_SECONDS;

	/** Longer than the largest retry delay, so scheduled retries run first. */
	const STALE_PENDING = 30 * MINUTE_IN_SECONDS;

	/**
	 * Past this age a pending batch is no longer worth sending (an order
	 * update a day late is noise), and a re-sent orphan could fall outside
	 * the API's 24 hour Idempotency-Key window.
	 */
	const GIVE_UP_AFTER = 12 * HOUR_IN_SECONDS;

	/**
	 * Hook everything.
	 */
	public static function register(): void {
		add_filter( 'cron_schedules', array( __CLASS__, 'schedules' ) ); // phpcs:ignore WordPress.WP.CronInterval.CronSchedulesInterval -- ten minutes is intended.
		add_action( self::HOOK, array( __CLASS__, 'run' ) );
		// Cron cleaner plugins sometimes drop events; put it back.
		add_action( 'init', array( __CLASS__, 'ensure_scheduled' ) );
	}

	/**
	 * Add the ten minute interval.
	 *
	 * @param array<string, array{interval: int, display: string}> $schedules Schedules.
	 * @return array<string, array{interval: int, display: string}>
	 */
	public static function schedules( $schedules ) {
		$schedules = is_array( $schedules ) ? $schedules : array();
		$schedules[ self::SCHEDULE ] = array(
			'interval' => 10 * MINUTE_IN_SECONDS,
			// Not translated: cron_schedules can run before translations load.
			'display'  => 'Every 10 minutes (Vibrate SMS)',
		);
		return $schedules;
	}

	/**
	 * Schedule the recurring job if it is missing.
	 */
	public static function ensure_scheduled(): void {
		if ( ! wp_next_scheduled( self::HOOK ) ) {
			wp_schedule_event( time() + 5 * MINUTE_IN_SECONDS, self::SCHEDULE, self::HOOK );
		}
	}

	/**
	 * Remove scheduled jobs (deactivation, uninstall).
	 */
	public static function unschedule(): void {
		wp_clear_scheduled_hook( self::HOOK );
		wp_unschedule_hook( Messenger::DISPATCH_HOOK );
		if ( function_exists( 'as_unschedule_all_actions' ) && did_action( 'action_scheduler_init' ) ) {
			as_unschedule_all_actions( Messenger::DISPATCH_HOOK );
		}
	}

	/**
	 * The recurring job.
	 */
	public static function run(): void {
		$started = time();
		self::recover();
		self::refresh( self::RUNS_PER_TICK, $started );
		self::purge();
	}

	/**
	 * Re-dispatch orphaned batches, or give up on ones that are too old.
	 */
	public static function recover(): void {
		$give_up_before = time() - self::GIVE_UP_AFTER;

		foreach ( Log::stale_sending( self::STALE_SENDING ) as $batch ) {
			$key = (string) $batch->batch_key;
			if ( strtotime( $batch->created_at . ' UTC' ) < $give_up_before ) {
				Log::update_batch(
					$key,
					'sending',
					array(
						'status'        => 'failed',
						'error_code'    => 'dispatch_interrupted',
						'error_message' => __( 'Sending was interrupted and could not be confirmed. Check the sent messages in the Vibrate app before sending again.', 'vibrate-sms' ),
					)
				);
				continue;
			}
			// Same Idempotency-Key: if Vibrate already took it, it replays.
			Log::update_batch( $key, 'sending', array( 'status' => 'pending' ) );
			Messenger::dispatch( $key );
		}

		foreach ( Log::stale_pending( self::STALE_PENDING ) as $key ) {
			$rows = Log::batch( $key );
			if ( $rows && strtotime( $rows[0]->created_at . ' UTC' ) < $give_up_before ) {
				Log::update_batch(
					$key,
					'pending',
					array(
						'status'        => 'failed',
						'error_code'    => 'expired',
						'error_message' => __( 'Not sent: the background queue did not run in time. Check that WP-Cron or Action Scheduler is working on this site.', 'vibrate-sms' ),
					)
				);
				continue;
			}
			Messenger::dispatch( $key );
		}
	}

	/**
	 * Pull delivery status for runs that are still open.
	 *
	 * @param int $limit   Runs to check.
	 * @param int $started Start time, for the time budget.
	 * @param int $settle  Skip runs checked less than this many seconds ago.
	 * @return int Runs checked.
	 */
	public static function refresh( int $limit, int $started = 0, int $settle = MINUTE_IN_SECONDS ): int {
		if ( '' === Settings::token() ) {
			return 0;
		}
		$started = $started ? $started : time();
		$checked = 0;
		foreach ( Log::open_runs( $limit, $settle ) as $run_id ) {
			if ( time() - $started > self::TIME_BUDGET ) {
				break;
			}
			Messenger::refresh_run( $run_id );
			++$checked;
		}
		return $checked;
	}

	/**
	 * Prune the log once a day.
	 */
	public static function purge(): void {
		$last = (int) get_option( self::PURGE_OPTION, 0 );
		if ( time() - $last < DAY_IN_SECONDS ) {
			return;
		}
		update_option( self::PURGE_OPTION, time(), false );
		$days = (int) Settings::protection()['log_retention_days'];
		if ( $days > 0 ) {
			Log::purge( $days );
		}
	}
}