// server.js  —— 零依赖反向代理版
const http = require('http');
const https = require('https');
const fs = require('fs');
const path = require('path');
const url = require('url');

// 读取配置
const configPath = process.env.CONFIG_PATH || './runtime-config.json';
const config = JSON.parse(fs.readFileSync(configPath, 'utf8'));
//const ROOT = path.join(__dirname, 'dist', 'h5');
const PORT = config["local-port"];
const REMOTE = config["remote-host"];//'http://101.43.219.60:7700';

const mime = { '.html': 'text/html', '.js': 'application/javascript', '.css': 'text/css', '.json': 'application/json', '.png': 'image/png', '.jpg': 'image/jpeg', '.gif': 'image/gif', '.svg': 'image/svg+xml', '.ico': 'image/x-icon' };

/* ------- 代理函数 ------- */
function proxyToRemote(req, res) {
    const parsed = url.parse(req.url);          // /dr/xxx?query
    const path = parsed.path;
    const target = url.parse(REMOTE);
    const options = {
        hostname: target.hostname,
        port: target.port || (target.protocol === 'https:' ? 443 : 80),
        path: path + (parsed.search || ''),
        method: req.method,
        headers: { ...req.headers }              // 原样带过去
    };
    // 删除本地头，避免 host 不匹配
    delete options.headers.host;
    delete options.headers.origin;
    delete options.headers.referer;

    console.log('Options:', options);
    console.log('Path:', options.path);
    const proxyReq = (target.protocol === 'https:' ? https : http).request(options, (proxyRes) => {
        // 把远端响应头原样写给浏览器
        res.writeHead(proxyRes.statusCode, proxyRes.headers);
        proxyRes.pipe(res);
    }).on('error', e => {
        console.error('[proxy error]', e.message);
        res.writeHead(502).end('Bad Gateway');
    });
    req.pipe(proxyReq);   // 把浏览器发来的 body 也转发过去
}

/* ------- 静态文件服务函数 ------- */
function serveStatic(req, res) {
    const parsed = url.parse(req.url, true);
    let pathname = parsed.pathname;

    // 默认索引
    if (pathname === '/') pathname = '/index.html';

    // 安全限制：禁止跳出 static
    const safePath = path.normalize(decodeURIComponent(pathname));
    const STATIC_DIR = path.resolve(config.staticPath || './static');
    const filePath = path.join(STATIC_DIR, safePath);
    if (!filePath.startsWith(STATIC_DIR)) {
        res.statusCode = 403;
        res.end('Forbidden');
        return;
    }
    fs.readFile(filePath, (err, data) => {
        if (err) {
            if (err.code === 'ENOENT') {
                res.statusCode = 404;
                res.end('Not Found');
            } else {
                res.statusCode = 500;
                res.end('Internal Server Error');
            }
            return;
        }

        const ext = path.extname(filePath).toLowerCase();
        res.setHeader('Content-Type', mime[ext] || 'application/octet-stream');
        res.end(data);
    });
}

/* ------- 主入口 ------- */

http.createServer((req, res) => {
    // 1. 预检直接 200
    if (req.method === 'OPTIONS') { res.writeHead(200); res.end(); return; }

    // 2. 路径以 /dr 开头 → 代理
    if (req.url.startsWith('/dr')) { proxyToRemote(req, res); return; }

    // 3. 其它 → 静态文件
    serveStatic(req, res);
}).listen(PORT, () => console.log(`> H5 running at http://localhost:${PORT}`));