const express = require('express');
const path = require('path');
const { spawn } = require('child_process');
const cors = require('cors');

const app = express();
const PORT = process.env.NODE_ENV === 'development' ? 8080 : 3000;
const SCREENSHOTS_DIR = path.join(__dirname, 'screenshots');
const CLIENT_DIST_DIR = process.env.NODE_ENV === 'development' ? path.join(__dirname, '../client/dist') : path.join(__dirname, './public');

function parseK6StdoutTable(text) {
  const keysToKeep = new Set([
    'checks_total',
    'checks_succeeded',
    'checks_failed',
    'browser_data_received',
    'browser_data_sent',
    'browser_http_req_duration',
    'browser_http_req_failed',
    'browser_web_vital_cls',
    'browser_web_vital_fcp',
    'browser_web_vital_ttfb',
    'checks',
    'data_received',
    'data_sent',
    'iteration_duration',
    'iterations',
    'vus',
    'vus_max'
  ]);

  const lines = text.split('\n');
  const result = {};

  for (let line of lines) {
    line = line.replace(/^[✓×\s]+/, ''); // 去掉开头 ✓ × 空格

    if (!line.includes(':')) continue;

    let [keyPart, valPart] = line.split(':');
    if (!valPart) continue;

    const key = keyPart.trim().replace(/\.+$/, '');
    if (!keysToKeep.has(key)) continue;

    valPart = valPart.trim();

    if (/(\w+\()?=/.test(valPart)) {
      const stats = {};
      const regex = /([^\s=]+)=([^\s]+)/g;
      let match;
      while ((match = regex.exec(valPart)) !== null) {
        stats[match[1]] = match[2];
      }
      result[key] = stats;

    } else {
      const parts = valPart.split(/\s+/);

      if (parts.length === 4 && parts[2].endsWith('/s')) {
        result[key] = {
          value: parts[0] + ' ' + parts[1],
          rate: parts[2] + ' ' + parts[3],
        };
      } else if (parts.length === 2 && parts[1].endsWith('/s')) {
        result[key] = {
          value: parts[0],
          rate: parts[1],
        };
      } else {
        result[key] = valPart;
      }
    }
  }

  return result;
}




// ====== 中间件 ======
app.use(cors());

// 静态资源
app.use('/static', express.static(SCREENSHOTS_DIR));
app.use(express.static(CLIENT_DIST_DIR));


// ====== API 路由 ======
app.get('/api/k6', async (req, res) => {
  const targetUrl = req.query.targetUrl;
  const timeStamp = req.query.timeStamp;
  console.log("targetUrl:", targetUrl);
  console.log("timeStamp:", timeStamp);

  if (!targetUrl || !timeStamp) {
    return res.status(400).json({ error: '缺少 targetUrl 或 timeStamp 参数' });
  }

  // 运行 k6 脚本
  const k6Process = spawn('k6', ['run', '--no-color=false', '--env', 'targetUrl=' + targetUrl, '--env', 'timeStamp=' + timeStamp, './script-browser.js']);

  let outputBuffer = '';
  k6Process.stdout.on('data', (chunk) => {
    outputBuffer += chunk.toString();
    console.log(chunk.toString())
  });

  k6Process.on('close', () => {
    const parsed = parseK6StdoutTable(outputBuffer);
    res.json(parsed); // 返回结构化结果给前端
  });
});

// ====== history 路由兼容（放在所有 API 路由之后） ======
app.get('*', (req, res) => {
  res.sendFile(path.join(CLIENT_DIST_DIR, 'index.html'));
});

// ====== 启动服务 ======
app.listen(PORT, () => {
  console.log(`Express server running at http://localhost:${PORT}`);
});