<?php
/**
 * 工单号生成：前缀 + 年月日 + 6 位随机数字，冲突时重试。
 *
 * 与订单号（20/22 位纯数字）区分：工单号对外可读、可口头传达，
 * 形如 T20261025XXXXXX。
 *
 * @package AKSRT
 */

namespace AKSRT\Ticket;

defined('ABSPATH') || exit;

final class TicketNumber {

    private const MAX_ATTEMPTS = 12;

    public static function generate(): string {
        $prefix = TicketSettings::number_prefix();
        $date = current_time('Ymd');

        for ($attempt = 0; $attempt < self::MAX_ATTEMPTS; $attempt++) {
            $candidate = $prefix . $date . wp_rand(100000, 999999);
            if (!self::exists($candidate)) {
                return $candidate;
            }
        }

        // 极端冲突下追加随机后缀，保证仍可落库（uniq_ticket_num 会兜底）。
        return $prefix . $date . wp_rand(100000, 999999) . wp_rand(100, 999);
    }

    private static function exists(string $ticket_num): bool {
        global $wpdb;
        $table = \AKSRT\Core\DBMigrator::table('ticket');
        if ($table === '') {
            return false;
        }
        $found = $wpdb->get_var($wpdb->prepare(
            "SELECT id FROM {$table} WHERE ticket_num = %s LIMIT 1", // phpcs:ignore WordPress.DB.PreparedSQL
            $ticket_num
        ));
        return $found !== null;
    }
}