import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

const errorRate = new Rate('errors');
const responseTime = new Trend('response_time');

export const options = {
  stages: [
    { duration: '1m', target: 50 },   // 1分钟内增加到50用户
    { duration: '2m', target: 100 },  // 2分钟内增加到100用户
    { duration: '3m', target: 200 },  // 3分钟内增加到200用户
    { duration: '5m', target: 300 },  // 5分钟内增加到300用户（压力峰值）
    { duration: '2m', target: 100 },  // 2分钟内减少到100用户
    { duration: '1m', target: 0 },    // 1分钟内减少到0
  ],
  thresholds: {
    http_req_duration: ['p(95)<1000', 'p(99)<2000'],  // 95%请求<1s, 99%请求<2s
    http_req_failed: ['rate<0.05'],  // 错误率<5%（压力测试允许更高）
    errors: ['rate<0.05'],
  },
};

const BASE_URL = __ENV.BASE_URL || 'http://localhost:3000';

export default function () {
  const scenarios = [
    { method: 'GET', path: '/', name: '首页' },
    { method: 'GET', path: '/api/health', name: '健康检查' },
    { method: 'POST', path: '/api/contact', name: '联系表单', body: JSON.stringify({
      name: 'Test User',
      email: 'test@example.com',
      phone: '13800138000',
      message: 'This is a test message',
    }) },
  ];

  const scenario = scenarios[Math.floor(Math.random() * scenarios.length)];
  
  let res;
  if (scenario.method === 'POST') {
    res = http.post(`${BASE_URL}${scenario.path}`, scenario.body, {
      headers: { 'Content-Type': 'application/json' },
      tags: { name: scenario.name },
    });
  } else {
    res = http.get(`${BASE_URL}${scenario.path}`, {
      tags: { name: scenario.name },
    });
  }

  const success = check(res, {
    'status is 200 or 201': (r) => [200, 201].includes(r.status),
    'response time < 1000ms': (r) => r.timings.duration < 1000,
  });

  errorRate.add(!success);
  responseTime.add(res.timings.duration);

  sleep(Math.random() * 2 + 0.5);  // 0.5-2.5秒随机等待
}

export function handleSummary(data) {
  return {
    'performance/stress-test-summary.json': JSON.stringify(data, null, 2),
  };
}