// server.js
const http = require('http');
const os = require('os');
const fs = require('fs');
const { exec } = require('child_process');

// --- Hugging Face Spaces 核心配置 ---
const HOST = '0.0.0.0';
const PORT = process.env.PORT || 7860;

// --- 辅助函数：获取磁盘使用情况（需要处理 /data 可能不存在）---
function getDiskUsage() {
    try {
        // 获取当前工作目录所在的文件系统（通常是容器根目录）
        const stats = fs.statfsSync('/');
        const total = stats.bsize * stats.blocks;
        const free = stats.bsize * stats.bfree;
        const used = total - free;
        const usagePercent = ((used / total) * 100).toFixed(2);
        return {
            total: (total / (1024 ** 3)).toFixed(2),
            used: (used / (1024 ** 3)).toFixed(2),
            free: (free / (1024 ** 3)).toFixed(2),
            usagePercent: `${usagePercent}%`
        };
    } catch (error) {
        return { error: '无法获取磁盘信息' };
    }
}

// --- 辅助函数：获取出口公网IP---
function getPublicIP() {
    return new Promise(resolve => {
        exec('curl -s --max-time 5 ifconfig.me', (err, stdout) => {
            if (err) resolve('无法获取公网IP (可能为NAT环境)');
            else resolve(stdout.trim());
        });
    });
}

// --- 辅助函数：安全获取环境变量---
function getSafeEnvVars() {
    const safeVars = {};
    const sensitiveKeys = ['PASSWORD', 'SECRET', 'TOKEN', 'KEY'];
    for (const [key, value] of Object.entries(process.env)) {
        if (sensitiveKeys.some(k => key.toLowerCase().includes(k.toLowerCase()))) {
            safeVars[key] = '****** (已隐藏)';
        } else {
            safeVars[key] = value;
        }
    }
    return safeVars;
}

// --- 辅助函数：检查 /data 目录状态（兼容不存在的情况）---
function checkDataDir() {
    try {
        if (fs.existsSync('/data')) {
            // 目录存在，检查是否可写
            fs.accessSync('/data', fs.constants.W_OK);
            return { exists: true, writable: true };
        } else {
            return { exists: false, writable: false, reason: '目录不存在（免费层未挂载持久存储）' };
        }
    } catch (err) {
        return { exists: true, writable: false, reason: err.message };
    }
}

// --- 创建 HTTP 服务器 ---
const server = http.createServer(async (req, res) => {
    // 1. 动态信息
    const publicIP = await getPublicIP();
    const diskInfo = getDiskUsage();
    const dataDirStatus = checkDataDir();
    
    // 2. 系统与硬件信息
    const cpuInfo = os.cpus()[0];
    const totalMem = (os.totalmem() / (1024 ** 3)).toFixed(2);
    const freeMem = (os.freemem() / (1024 ** 3)).toFixed(2);
    const usedMem = (totalMem - freeMem).toFixed(2);
    const systemUptime = Math.floor(os.uptime() / 60) + ' 分钟';
    
    // 3. 用户ID和权限
    let userId = null, groupId = null;
    try {
        userId = process.getuid();
        groupId = process.getgid();
    } catch(e) { /* Windows 可能不支持 */ }
    
    // 4. 构建环境报告
    const envReport = {
        // 访问信息
        access: {
            spaceUrl: `https://${process.env.SPACE_ID?.replace('/', '-') || 'unknown'}.hf.space`,
            publicIP: publicIP,
            internalIP: (() => {
                const interfaces = os.networkInterfaces();
                for (const iface of Object.values(interfaces)) {
                    for (const addr of iface) {
                        if (addr.family === 'IPv4' && !addr.internal) return addr.address;
                    }
                }
                return '127.0.0.1';
            })(),
            hostname: os.hostname(),
            spaceId: process.env.SPACE_ID || '未设置',
            spaceRepoName: process.env.SPACE_REPO_NAME || '未设置',
        },
        // 硬件资源
        hardware: {
            cpuModel: cpuInfo?.model || '未知',
            cpuCores: os.cpus().length,
            totalRamGB: totalMem,
            usedRamGB: usedMem,
            freeRamGB: freeMem,
            disk: diskInfo,
            uptime: systemUptime,
            expectedFreeTier: '2 vCPU / 16GB RAM / 50GB 临时磁盘'
        },
        // Node.js 环境
        nodeEnv: {
            version: process.version,
            platform: process.platform,
            arch: process.arch,
            execPath: process.execPath,
            cwd: process.cwd(),
        },
        // 容器与权限
        container: {
            userId: userId,
            groupId: groupId,
            expectedUserId: '通常为 1000 (node 用户)',
            isDataDirPresent: dataDirStatus.exists,
            isDataDirWritable: dataDirStatus.writable,
            dataDirDetail: dataDirStatus.reason || (dataDirStatus.writable ? '可写' : '不可写'),
            hfHome: process.env.HF_HOME || '未设置',
            persistentStorageAvailable: dataDirStatus.exists && dataDirStatus.writable,
        },
        // 关键环境变量（安全过滤）
        envVars: getSafeEnvVars(),
        // 部署建议
        suggestions: [
            '✅ 必须监听 0.0.0.0，并在 README.md 中设置 app_port: 7860',
            '✅ 强烈建议为敏感信息使用 HF Secrets，勿硬编码',
            '✅ 免费层磁盘非持久化，重启会丢失数据',
            '✅ 如需持久化，考虑升级 Persistent Storage 或将数据备份到 HF Dataset',
            '✅ 容器默认用户 UID 可能为 1000，Dockerfile 中建议使用现有 node 用户',
        ]
    };
    
    res.writeHead(200, { 'Content-Type': 'application/json; charset=utf-8' });
    res.end(JSON.stringify(envReport, null, 2));
});

// 启动服务器
server.listen(PORT, HOST, () => {
    console.log(`🔍 Hugging Face Spaces 环境探针已启动`);
    console.log(`📡 监听地址: http://${HOST}:${PORT}`);
    console.log(`🌐 公网访问: https://${process.env.SPACE_ID?.replace('/', '-') || 'your-space'}.hf.space`);
    console.log(`💡 提示: 访问上述 URL 即可查看详细的环境报告 JSON`);
});