<?php
/**
 * Daily prune of old hits. Visitor rows keep the lifetime totals, so pruning
 * loses nothing the reports need.
 */

defined( 'ABSPATH' ) || exit;

final class Saddle_Analytics_Cron {

	const HOOK = 'saddle_analytics_daily_prune';

	public static function schedule(): void {
		if ( ! wp_next_scheduled( self::HOOK ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, 'daily', self::HOOK );
		}
	}

	public static function unschedule(): void {
		wp_clear_scheduled_hook( self::HOOK );
	}

	/** The retention_days setting (Phase 34); the filter can still override it in code. */
	public static function retention_days(): int {
		return max( Saddle_Analytics_Settings::RETENTION_MIN, (int) apply_filters( 'saddle_analytics_hits_retention', (int) Saddle_Analytics_Settings::get( 'retention_days' ) ) );
	}

	/**
	 * Delete hits older than the retention window, in batches.
	 *
	 * @return int Rows deleted (or that would be, when $dry_run).
	 */
	public static function prune( bool $dry_run = false ): int {
		global $wpdb;
		if ( Saddle_Analytics_Migrate::blocking() ) {
			return 0; // The tables may not exist yet.
		}
		$hits   = Saddle_Analytics_Install::tables()['hits'];
		$cutoff = gmdate( 'Y-m-d H:i:s', time() - self::retention_days() * DAY_IN_SECONDS );

		if ( $dry_run ) {
			$crawlers = Saddle_Analytics_Install::tables()['crawlers'];
			return (int) $wpdb->get_var(
				$wpdb->prepare( 'SELECT COUNT(*) FROM %i WHERE ts < %s', $hits, $cutoff )
			) + (int) $wpdb->get_var(
				$wpdb->prepare( 'SELECT COUNT(*) FROM %i WHERE day < %s', $crawlers, gmdate( 'Y-m-d', time() - self::retention_days() * DAY_IN_SECONDS ) )
			);
		}

		$total   = 0;
		$batches = 0;
		do {
			$deleted = (int) $wpdb->query(
				$wpdb->prepare( 'DELETE FROM %i WHERE ts < %s LIMIT 10000', $hits, $cutoff )
			);
			$total  += $deleted;
		} while ( $deleted > 0 && ++$batches < 30 ); // A huge backlog finishes across daily runs, not one tick.

		// The crawler rollup ages out with the hits (Phase 18) — at one row per
		// bot per day it never needs batching.
		$total += Saddle_Analytics::crawlers()->prune( self::retention_days() );

		return $total;
	}
}