/**
 * 爬虫检测中间件
 * 用于识别和区分搜索引擎爬虫和正常用户访问
 */

// 常见搜索引擎爬虫的User-Agent列表
const SEARCH_ENGINE_BOTS = [
    // Google
    'googlebot',
    'googlebot-image',
    'googlebot-news',
    'mediapartners-google',
    'adsbot-google',

    // 百度
    'baiduspider',
    'baiduspider-mobile',

    // 必应
    'bingbot',
    'msnbot',

    // 360
    '360spider',

    // 搜狗
    'sogou spider',
    'sogou-orion',

    // 雅虎
    'slurp',
    'yahoo',

    // Yandex
    'yandex',

    // DuckDuckGo
    'duckduckbot',

    // 头头条
    'bytespider',

    // 神马
    'yisouspider',

    // 其他
    'spider',
    'crawl',
    'bot',
    'curl',
    'wget',
];

// 爬虫检测函数
export function isCrawler(userAgent) {
    if (!userAgent) {
        return false;
    }

    const ua = userAgent.toLowerCase();

    // 检查是否匹配已知的爬虫User-Agent
    return SEARCH_ENGINE_BOTS.some(bot => ua.includes(bot));
}

// Node.js Express 中间件
export function crawlerMiddleware(options = {}) {
    const {
        staticPagesPath = '../static-pages',
        fallbackPath = '/index.html',
        debug = false
    } = options;

    return (req, res, next) => {
        const userAgent = req.headers['user-agent'];

        // 检测是否是爬虫
        if (isCrawler(userAgent)) {
            if (debug) {
                console.log(`🕷️  检测到爬虫: ${userAgent}`);
                console.log(`📍 请求路径: ${req.path}`);
            }

            // 尝试返回对应的静态页面
            const path = require('path');
            const fs = require('fs');

            const staticDir = path.join(__dirname, staticPagesPath);

            // 将路径转换为文件名
            let filename = req.path
                .replace(/^\//, '')
                .replace(/\/+/g, '-')
                .replace(/:/g, '-');

            if (!filename) {
                filename = 'index';
            }

            const filepath = path.join(staticDir, `${filename}.html`);

            // 检查静态文件是否存在
            if (fs.existsSync(filepath)) {
                if (debug) {
                    console.log(`📄 返回静态页面: ${filepath}`);
                }

                const html = fs.readFileSync(filepath, 'utf-8');
                res.setHeader('Content-Type', 'text/html; charset=utf-8');
                res.send(html);
                return;
            } else {
                if (debug) {
                    console.log(`⚠️  静态页面不存在: ${filepath}`);
                }
            }
        }

        // 正常用户或未找到静态页面，继续处理
        next();
    };
}

// Nginx 配置生成器
export function generateNginxConfig(options = {}) {
    const {
        serverName = 'www.tianyuancha.cn',
        spaRoot = '/var/www/tyc-webview-v2/dist',
        staticRoot = '/var/www/tyc-webview-v2/static-pages',
        sslEnabled = false,
        sslCertPath = '',
        sslKeyPath = ''
    } = options;

    const protocol = sslEnabled ? 'https' : 'http';
    const listenPort = sslEnabled ? '443 ssl' : '80';
    const sslConfig = sslEnabled ? `
    ssl_certificate ${sslCertPath};
    ssl_certificate_key ${sslKeyPath};
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
` : '';

    const httpRedirect = sslEnabled ? `
# HTTP 重定向到 HTTPS
server {
    listen 80;
    server_name ${serverName};
    return 301 https://$server_name$request_uri;
}
` : '';

    return `# Nginx 配置文件 - 天远查 SPA + SEO 静态页面
# 自动生成时间: ${new Date().toLocaleString('zh-CN')}

${httpRedirect}

server {
    listen ${listenPort};
    server_name ${serverName};
    charset utf-8;

${sslConfig}
    # 日志配置
    access_log /var/log/nginx/${serverName}-access.log;
    error_log /var/log/nginx/${serverName}-error.log;

    # 爬虫检测
    set $is_bot 0;

    # Google
    if ($http_user_agent ~* (googlebot|googlebot-image|googlebot-news|mediapartners-google|adsbot-google)) {
        set $is_bot 1;
    }

    # 百度
    if ($http_user_agent ~* (baiduspider|baiduspider-mobile)) {
        set $is_bot 1;
    }

    # 必应
    if ($http_user_agent ~* (bingbot|msnbot)) {
        set $is_bot 1;
    }

    # 360
    if ($http_user_agent ~* "360spider") {
        set $is_bot 1;
    }

    # 搜狗
    if ($http_user_agent ~* "(sogou spider|sogou-orion)") {
        set $is_bot 1;
    }

    # 其他爬虫
    if ($http_user_agent ~* "(spider|crawl|bot|slurp|yandex|duckduckbot|bytespider|yisouspider)") {
        set $is_bot 1;
    }

    # 根路径处理
    location = / {
        if ($is_bot = 1) {
            root ${staticRoot};
            try_files /index.html /index.html;
            break;
        }
        root ${spaRoot};
        try_files $uri $uri/ /index.html;
    }

    # 静态页面处理
    location ~ ^/([^/]+)(/.*)?$ {
        # 将路径转换为文件名
        set $static_filename $1;
        set $rest_path $2;

        if ($is_bot = 1) {
            root ${staticRoot};
            try_files /$static_filename.html /index.html;
            break;
        }
        root ${spaRoot};
        try_files $uri $uri/ /index.html;
    }

    # SPA 路由回退
    location / {
        root ${spaRoot};
        try_files $uri $uri/ /index.html;
        add_header Cache-Control "no-cache";
    }

    # 静态资源缓存
    location ~* \\.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
        root ${spaRoot};
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    # API 代理
    location /api/ {
        proxy_pass http://localhost:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_cache_bypass $http_upgrade;
    }

    # Gzip 压缩
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml+rss application/javascript application/json;

    # 安全头
    add_header X-Frame-Options "SAMEORIGIN";
    add_header X-Content-Type-Options "nosniff";
    add_header X-XSS-Protection "1; mode=block";
}
`;
}

// 生成 .htaccess 文件（Apache）
export function generateHtaccessConfig(options = {}) {
    const {
        staticRoot = '/static-pages',
        spaRoot = '/'
    } = options;

    return `# Apache .htaccess 配置 - 天远查 SPA + SEO 静态页面
# 自动生成时间: ${new Date().toLocaleString('zh-CN')}

# 启用重写引擎
RewriteEngine On

# 爬虫检测
RewriteCond %{HTTP_USER_AGENT} (googlebot|googlebot-image|googlebot-news|mediapartners-google|adsbot-google) [NC,OR]
RewriteCond %{HTTP_USER_AGENT} (baiduspider|baiduspider-mobile) [NC,OR]
RewriteCond %{HTTP_USER_AGENT} (bingbot|msnbot) [NC,OR]
RewriteCond %{HTTP_USER_AGENT} "360spider" [NC,OR]
RewriteCond %{HTTP_USER_AGENT} (sogou spider|sogou-orion) [NC,OR]
RewriteCond %{HTTP_USER_AGENT} (spider|crawl|bot|slurp|yandex|duckduckbot|bytespider|yisouspider) [NC]

# 爬虫访问静态页面
RewriteRule ^$ ${staticRoot}/index.html [L]
RewriteRule ^([^/]+)/?$ ${staticRoot}/$1.html [L]
RewriteRule ^([^/]+)/(.+)$ ${staticRoot}/$1.html [L]

# 正常用户访问 SPA
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . ${spaRoot}index.html [L]

# Gzip 压缩
<IfModule mod_deflate.c>
    AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css text/javascript application/javascript application/json
</IfModule>

# 缓存控制
<IfModule mod_expires.c>
    ExpiresActive On
    ExpiresByType image/jpg "access plus 1 year"
    ExpiresByType image/jpeg "access plus 1 year"
    ExpiresByType image/gif "access plus 1 year"
    ExpiresByType image/png "access plus 1 year"
    ExpiresByType text/css "access plus 1 month"
    ExpiresByType application/javascript "access plus 1 month"
</IfModule>

# 安全头
<IfModule mod_headers.c>
    Header set X-Frame-Options "SAMEORIGIN"
    Header set X-Content-Type-Options "nosniff"
    Header set X-XSS-Protection "1; mode=block"
</IfModule>
`;
}

// 导出工具函数
export { SEARCH_ENGINE_BOTS };