<?php
// +----------------------------------------------------------------------
// | YwxApp [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2026-2036 http://ywxapp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Author: ywxapp<admin@ywxapp.cn>
// +----------------------------------------------------------------------
declare(strict_types=1);

namespace ywxapp\library;

/**
 * 搜索引擎蜘蛛识别
 *
 * 仅按 User-Agent 特征串识别（不做 DNS 反查，保证零阻塞）。
 * 新增蜘蛛只需在 SPIDERS 追加一行：标识 => [UA特征串列表, 显示名]。
 *
 * @author ywxapp <admin@ywxapp.cn>
 */
class SpiderDetect
{
    /**
     * 蜘蛛特征表：key=入库标识，value=[UA 特征串（不区分大小写，命中任一即算）, 中文显示名]
     */
    public const SPIDERS = [
        'baidu'      => [['Baiduspider'], '百度'],
        'google'     => [['Googlebot', 'Google-InspectionTool', 'AdsBot-Google'], '谷歌'],
        'bing'       => [['bingbot', 'msnbot', 'BingPreview'], '必应'],
        'sogou'      => [['Sogou web spider', 'Sogou inst spider', 'Sogou Pic Spider'], '搜狗'],
        'so360'      => [['360Spider', 'HaoSouSpider', 'qihoobot'], '360'],
        'bytedance'  => [['Bytespider', 'ToutiaoSpider'], '字节跳动'],
        'shenma'     => [['YisouSpider'], '神马'],
        'huawei'     => [['PetalBot'], '华为花瓣'],
        'yandex'     => [['YandexBot'], 'Yandex'],
        'duckduckgo' => [['DuckDuckBot', 'DuckDuckGo-Favicons-Bot'], 'DuckDuckGo'],
        'yahoo'      => [['Yahoo! Slurp'], '雅虎'],
        'apple'      => [['Applebot'], '苹果'],
        'gptbot'     => [['GPTBot', 'ChatGPT-User', 'OAI-SearchBot'], 'OpenAI'],
        'claudebot'  => [['ClaudeBot', 'anthropic-ai'], 'Anthropic'],
        'semrush'    => [['SemrushBot'], 'Semrush'],
        'ahrefs'     => [['AhrefsBot'], 'Ahrefs'],
        'mj12'       => [['MJ12bot'], 'Majestic'],
        'facebook'   => [['facebookexternalhit', 'FacebookBot'], 'Facebook'],
    ];

    /**
     * 识别 UA，命中返回蜘蛛标识（SPIDERS 的 key），未命中返回 null
     */
    public static function detect(string $userAgent): ?string
    {
        if ($userAgent === '') {
            return null;
        }
        foreach (self::SPIDERS as $key => [$needles]) {
            foreach ($needles as $needle) {
                if (stripos($userAgent, $needle) !== false) {
                    return $key;
                }
            }
        }
        return null;
    }

    /**
     * 蜘蛛标识 → 中文显示名（未知标识原样返回）
     */
    public static function label(string $key): string
    {
        return self::SPIDERS[$key][1] ?? $key;
    }

    /**
     * 全部蜘蛛 标识=>显示名（后台下拉/报表用）
     */
    public static function labels(): array
    {
        $out = [];
        foreach (self::SPIDERS as $key => [, $label]) {
            $out[$key] = $label;
        }
        return $out;
    }
}