const http = require('http');
const https = require('https');
const url = require('url');

const PORT = 3000;
const MAX_RETRIES = 3;
const INITIAL_TIMEOUT = 3000; // 初始超时时间设置为3秒
const BACKOFF_FACTOR = 2; // 指数退避因子

const server = http.createServer((req, res) => {
    const reqUrl = url.parse(req.url, true);
    const id = reqUrl.pathname.split('/').pop();

    // 检查 ID 是否存在且格式正确
    if (!id || isNaN(id)) {
        res.writeHead(400, { 'Content-Type': 'text/plain' });
        res.end('Invalid ID');
        return;
    }

    const targetUrl = `https://xxxclub.to/torrents/details/${id}`;
    console.log(`Target URL: ${targetUrl}`);

    let responseSent = false;

    const makeRequest = (retryCount = 0, timeout = INITIAL_TIMEOUT) => {
        if (responseSent) return;

        const options = url.parse(targetUrl);
        options.method = 'GET';
        options.timeout = timeout;

        const proxyReq = https.request(options, (proxyRes) => {
            let data = '';

            proxyRes.on('data', (chunk) => {
                data += chunk;
            });

            proxyRes.on('end', () => {
                if (!responseSent) {
                    res.writeHead(proxyRes.statusCode, proxyRes.headers);
                    res.end(data);
                    responseSent = true;
                }
            });
        });

        proxyReq.on('timeout', () => {
            console.error('Request timed out.');
            proxyReq.abort();

            if (retryCount < MAX_RETRIES) {
                const newTimeout = timeout * BACKOFF_FACTOR;
                console.log(`Retrying... (${retryCount + 1}/${MAX_RETRIES}) with timeout ${newTimeout}ms`);
                makeRequest(retryCount + 1, newTimeout);
            } else if (!responseSent) {
                res.writeHead(504, { 'Content-Type': 'text/plain' });
                res.end('Request timed out.');
                responseSent = true;
            }
        });

        proxyReq.on('error', (e) => {
            console.error(`Problem with request: ${e.message}`);

            if (retryCount < MAX_RETRIES) {
                const newTimeout = timeout * BACKOFF_FACTOR;
                console.log(`Retrying... (${retryCount + 1}/${MAX_RETRIES}) with timeout ${newTimeout}ms`);
                makeRequest(retryCount + 1, newTimeout);
            } else if (!responseSent) {
                res.writeHead(500, { 'Content-Type': 'text/plain' });
                res.end('Error occurred while fetching the data.');
                responseSent = true;
            }
        });

        proxyReq.end();
    };

    makeRequest();
});

server.listen(PORT, () => {
    console.log(`Proxy server is running on http://localhost:${PORT}`);
});