<?php
if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

/**
 * Checker for 404 Scout. Pings URLs and updates their status in the DB.
 *
 * @since      1.0
 * @package    AILinkMaster
 * @subpackage AILinkMaster/modules/404-scout
 */

class AILM_Scout_Checker {

    /**
     * Checks a batch of links pending verification.
     *
     * @param int $batch_size The number of links to process in one run.
     * @return int The number of links processed.
     */
    public static function process_batch( $batch_size = 25 ) {
        global $wpdb;
        $table_name = $wpdb->prefix . 'ailm_link_monitor';

        // phpcs:ignore WordPress.DB.DirectDatabaseQuery
        $links = $wpdb->get_results( $wpdb->prepare(
            "SELECT id, url FROM %i WHERE status_code = %d ORDER BY id ASC LIMIT %d",
            $table_name,
            0,
            $batch_size
        ) );

        if ( empty( $links ) ) {
            return 0; // No links to check
        }

        $processed = 0;

        foreach ( $links as $link ) {
            $status_code = self::ping_url( $link->url );

            // Update status and check time in the database
            // phpcs:ignore WordPress.DB.DirectDatabaseQuery
            $wpdb->update(
                $table_name,
                array(
                    'status_code'  => $status_code,
                    'last_checked' => current_time( 'mysql' )
                ),
                array( 'id' => $link->id ),
                array( '%d', '%s' ),
                array( '%d' )
            );

            $processed++;
        }

        return $processed;
    }

    /**
     * Pings a URL to get its HTTP status.
     *
     * @param string $url The URL to check.
     * @return int HTTP code (200, 301, 404) or 500 on timeout/cURL error.
     */
    private static function ping_url( $url ) {
        $args = array(
            'timeout'     => 5,    // 5 second timeout to avoid hanging the server
            'redirection' => 5,    // Follow redirects
            'sslverify'   => false // Disable strict SSL verification to prevent false 500 errors from misconfigured certificates
        );

        // First, try a lightweight HEAD request (downloads only headers, saves bandwidth)
        $response = wp_remote_head( $url, $args );

        // Architectural trick: some servers or firewalls (like Cloudflare)
        // block HEAD requests, returning 405 Method Not Allowed or 403 Forbidden.
        // In that case, perform a regular GET request as a fallback.
        $code = wp_remote_retrieve_response_code( $response );
        if ( is_wp_error( $response ) || $code == 405 || $code == 403 ) {
            $response = wp_remote_get( $url, $args );
        }

        if ( is_wp_error( $response ) ) {
            return 500; // Connection error or timeout
        }

        return (int) wp_remote_retrieve_response_code( $response );
    }
}