<?php
/**
 * Bot and Search Referrer Detection
 */
class SC_Bot_Detector {

    private static $google_mobile_patterns = [
        '/Googlebot.*Android/i',
        '/Android.*Googlebot/i',
    ];

    private static $google_patterns = [
        '/Googlebot\//i',
        '/Googlebot-Mobile/i',
        '/Googlebot-Image/i',
        '/Googlebot-Video/i',
        '/Googlebot-News/i',
        '/Storebot-Google/i',
        '/Google-InspectionTool/i',
        '/GoogleOther/i',
        '/APIs-Google/i',
        '/AdsBot-Google/i',
        '/Mediapartners-Google/i',
        '/FeedFetcher-Google/i',
    ];

    private static $bing_patterns = [
        '/bingbot\//i',
        '/msnbot/i',
        '/BingPreview/i',
        '/adidxbot/i',
    ];

    private static $yandex_patterns = [
        '/YandexBot/i',
        '/YandexAccessibilityBot/i',
        '/YandexMobileBot/i',
        '/YandexDirectDyn/i',
        '/YandexImages/i',
        '/YandexVideo/i',
        '/YandexMedia/i',
        '/YandexBlogs/i',
        '/YandexFavicons/i',
        '/YandexWebmaster/i',
        '/YandexPagechecker/i',
        '/YandexImageResizer/i',
        '/YandexAdNet/i',
        '/YandexDirect/i',
        '/YandexMetrika/i',
        '/YandexNews/i',
        '/YandexCatalog/i',
    ];

    /**
     * Detect bot type from user-agent
     * IMPORTANT: For Google — only Google Android (mobile) bot is tracked.
     * Other Google bots are ignored (not detected as bot).
     * @return array ['is_bot' => bool, 'bot_type' => string|null]
     */
    public static function detect($user_agent = null) {
        if ($user_agent === null) {
            $user_agent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : '';
        }

        if (empty($user_agent)) {
            return ['is_bot' => false, 'bot_type' => null];
        }

        // Google: ONLY Android mobile bot is detected, all other Google bots are IGNORED
        foreach (self::$google_mobile_patterns as $pattern) {
            if (preg_match($pattern, $user_agent)) {
                return ['is_bot' => true, 'bot_type' => 'google'];
            }
        }

        // Other Google bots — intentionally NOT detected (skip $google_patterns)

        foreach (self::$bing_patterns as $pattern) {
            if (preg_match($pattern, $user_agent)) {
                return ['is_bot' => true, 'bot_type' => 'bing'];
            }
        }

        foreach (self::$yandex_patterns as $pattern) {
            if (preg_match($pattern, $user_agent)) {
                return ['is_bot' => true, 'bot_type' => 'yandex'];
            }
        }

        return ['is_bot' => false, 'bot_type' => null];
    }

    /**
     * Detect search engine referrer
     * @return array ['is_search' => bool, 'referrer_type' => string|null]
     */
    public static function detect_search_referrer($referrer = null) {
        if ($referrer === null) {
            $referrer = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '';
        }

        if (empty($referrer)) {
            return ['is_search' => false, 'referrer_type' => null];
        }

        $ref = strtolower($referrer);

        if (preg_match('/\b(google\.com|google\.co\.|google\.ru|google\.de|google\.fr|google\.es|google\.it|google\.com\.br|google\.ca|google\.com\.au|google\.co\.uk|google\.co\.jp)\b/', $ref)) {
            return ['is_search' => true, 'referrer_type' => 'google'];
        }

        if (preg_match('/\b(bing\.com)\b/', $ref)) {
            return ['is_search' => true, 'referrer_type' => 'bing'];
        }

        if (preg_match('/\b(yandex\.ru|yandex\.com|yandex\.by|yandex\.kz|yandex\.ua)\b/', $ref)) {
            return ['is_search' => true, 'referrer_type' => 'yandex'];
        }

        return ['is_search' => false, 'referrer_type' => null];
    }

    /**
     * Detect device type from user-agent
     */
    public static function detect_device($user_agent) {
        $ua = strtolower($user_agent);
        if (strpos($ua, 'android') !== false) return 'android';
        if (strpos($ua, 'iphone') !== false || strpos($ua, 'ipad') !== false) return 'iphone';
        if (strpos($ua, 'macintosh') !== false || strpos($ua, 'mac os') !== false) return 'mac';
        if (strpos($ua, 'windows') !== false) return 'windows';
        if (strpos($ua, 'linux') !== false) return 'linux';
        return 'other';
    }

    /**
     * Detect browser from user-agent
     */
    public static function detect_browser($user_agent) {
        if (preg_match('/Edg\//i', $user_agent)) return 'Edge';
        if (preg_match('/OPR\//i', $user_agent) || preg_match('/Opera/i', $user_agent)) return 'Opera';
        if (preg_match('/YaBrowser/i', $user_agent)) return 'Yandex Browser';
        if (preg_match('/Chrome\//i', $user_agent)) return 'Chrome';
        if (preg_match('/Firefox\//i', $user_agent)) return 'Firefox';
        if (preg_match('/Safari\//i', $user_agent) && !preg_match('/Chrome/i', $user_agent)) return 'Safari';
        if (preg_match('/MSIE|Trident/i', $user_agent)) return 'IE';
        return 'Other';
    }
}