<?php
/**
 * Free preload worker: processes queue via WP-Cron (homepage + manual URLs).
 * Sitemap / scheduled preload live in Pro.
 *
 * @package QWSpeedCache
 */
namespace QWSpeedCache\Preload;

defined( 'ABSPATH' ) || exit;

class Bot {

	const CRON         = 'qwsc_preload_batch';
	const STATS_OPTION = 'qwsc_preload_stats';

	public function __construct() {
		add_action( self::CRON, array( $this, 'process_batch' ) );
	}

	/**
	 * @param int $delay Seconds before first batch.
	 */
	public function schedule_process( $delay = 5 ) {
		if ( ! wp_next_scheduled( self::CRON ) ) {
			wp_schedule_single_event( time() + max( 1, (int) $delay ), self::CRON );
		}
	}

	public function process_batch() {
		// Pro/add-ons may supply their own worker while reusing this queue/cron hook.
		if ( apply_filters( 'qwsc_preload_worker_override', false ) ) {
			return;
		}
		$queue = Queue::get();
		list( $urls, $rest ) = Queue::take( $queue, 5 );
		Queue::set( $rest );
		if ( empty( $urls ) ) {
			return;
		}
		$done = 0;
		$failed = 0;
		foreach ( $urls as $url ) {
			$url = Queue::normalize_url( $url );
			$url = $url ? esc_url_raw( $url ) : ''; 
			if ( ! $url ) {
				continue;
			}
			$res = wp_safe_remote_get(
				$url,
				array(
					'timeout'     => 15,
					'redirection' => 0, // Never follow redirects to other hosts or private addresses.
					'user-agent'  => 'QWSpeedCache-Preload/' . ( defined( 'QWSC_VERSION' ) ? QWSC_VERSION : '1.0' ),
					'headers'     => array( 'X-QWSC-Preload' => '1' ),
				)
			);
			$code = is_wp_error( $res ) ? 0 : (int) wp_remote_retrieve_response_code( $res );
			if ( $code >= 200 && $code < 400 ) {
				$done++;
			} else {
				$failed++;
			}
			do_action( 'qwsc_preload_response', $url, $code );
		}
		$stats = get_option( self::STATS_OPTION, array() );
		if ( ! is_array( $stats ) ) {
			$stats = array();
		}
		$stats['last_run']   = time();
		$stats['done']       = (int) ( $stats['done'] ?? 0 ) + $done;
		$stats['failed']     = (int) ( $stats['failed'] ?? 0 ) + $failed;
		$stats['remaining']  = Queue::count();
		update_option( self::STATS_OPTION, $stats, false );
		update_option( 'qwsc_last_preload', time(), false );

		do_action( 'qwsc_preload_batch_finished', $done, $failed, Queue::count() );

		if ( Queue::count() > 0 ) {
			$this->schedule_process( 15 );
		}
	}

	/**
	 * Free build: schedule is always off (Pro feature).
	 */
	public static function sync_schedule( $schedule = 'off', $force = false ) {
		$hook = 'qwsc_preload_scheduled';
		$ts   = wp_next_scheduled( $hook );
		if ( $ts ) {
			wp_unschedule_event( $ts, $hook );
		}
		// Intentionally do not schedule — scheduled preload is Pro-only.
	}
}