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

// Custom metric to explicitly track the percentage of unauthorized requests
const unauthorizedRate = new Rate('unauthorized_rate');

export const options = {
  // Test scenario: 1000 virtual users executing 1 iteration each
  vus: 1000,
  iterations: 1000,
  // We can also define thresholds for CI/CD pipelines
  thresholds: {
    'http_req_duration': ['p(95)<500'], // 95% of requests must complete below 500ms
    'unauthorized_rate': ['rate==0'],   // 0% unauthorized errors (strict constraint)
  },
};

const BASE_URL = 'http://localhost:5064';

export default function () {
  // --- Setup / Login Phase ---
  // Each VU initializes its own secure session and receives a unique token.
  const initRes = http.post(`${BASE_URL}/Init`);
  
  check(initRes, {
    'init status is 200': (r) => r.status === 200,
    'init returned sequenceId': (r) => r.json('initialSequenceId') !== undefined,
  });

  if (initRes.status !== 200) {
    return; // Stop VU if init fails to prevent cascading errors
  }

  // Local state for the virtual user
  let currentToken = initRes.json('initialSequenceId');

  // --- Stateful Mutation Phase ---
  // The VU performs 50 sequential requests. In a real scenario, these would be GET/POST/PUT.
  for (let i = 0; i < 50; i++) {
    const res = http.get(`${BASE_URL}/Secure/data`, {
      headers: {
        'X-Auth-Seq': currentToken,
      },
    });

    const success = check(res, {
      'status is 200': (r) => r.status === 200,
      'has X-Next-Seq header': (r) => r.headers['X-Next-Seq'] !== undefined,
    });

    if (res.status === 401) {
      unauthorizedRate.add(1);
      console.error(`VU ${__VU} experienced sequence break on iteration ${i}! Received 401.`);
      break; // The chain is broken, stop further requests
    } else {
      unauthorizedRate.add(0);
    }

    if (success) {
      // Critical Step: Read X-Next-Seq from Response and save it for the next request in the chain
      currentToken = res.headers['X-Next-Seq'];
    }
    
    // Simulate real-world delay between operations (optional, but realistic)
    // sleep(Math.random() * 0.1); 
  }
}