// Backend/tests/k6/register-students.js
// สคริปสำหรับ register นักเรียน 50 คน
// email: studenttest01-50@example.com
// username: student01-50
// password: admin123

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

// Custom metrics
const errorRate = new Rate('errors');
const successCount = new Counter('successful_registrations');
const failCount = new Counter('failed_registrations');

// Configuration: Run 50 iterations sequentially (1 VU to avoid duplicate)
export const options = {
  iterations: 50,
  vus: 1, // 1 VU to ensure sequential registration (no duplicates)
  thresholds: {
    errors: ['rate<0.1'], // Error rate < 10%
    http_req_duration: ['p(95)<3000'], // 95% of requests < 3s
  },
};

const BASE_URL = __ENV.APP_URL || 'http://192.168.1.137:4000';

export default function () {
  // Calculate student number (1-50) based on iteration
  // __ITER is unique per iteration across all VUs
  const studentNum = __ITER + 1;
  const paddedNum = String(studentNum).padStart(2, '0');
  
  const email = `studenttest${paddedNum}@example.com`;
  const username = `student${paddedNum}`;
  const password = 'admin123';

  console.log(`Registering student: ${username} (${email})`);

  const payload = JSON.stringify({
    username: username,
    email: email,
    password: password,
    first_name: `Student`,
    last_name: `Test${paddedNum}`,
    prefix: {
      en: 'Mr.',
      th: 'นาย'
    },
    phone: `08${paddedNum}000000${paddedNum}`,
  });

  const headers = {
    'Content-Type': 'application/json',
  };

  const res = http.post(`${BASE_URL}/api/auth/register-learner`, payload, { headers });

  const isSuccess = res.status === 200 || res.status === 201;
  const isAlreadyExists = res.status === 400 && res.body && res.body.includes('already');

  errorRate.add(!isSuccess && !isAlreadyExists);

  if (isSuccess) {
    successCount.add(1);
    console.log(`✓ Successfully registered: ${username}`);
  } else if (isAlreadyExists) {
    console.log(`⚠ Already exists: ${username}`);
  } else {
    failCount.add(1);
    console.log(`✗ Failed to register: ${username} - Status: ${res.status} - ${res.body}`);
  }

  check(res, {
    'registration successful or already exists': (r) => r.status === 200 || r.status === 201 || r.status === 400,
    'response time < 3s': (r) => r.timings.duration < 3000,
  });

  sleep(0.5); // Small delay between registrations
}

export function handleSummary(data) {
  return {
    'stdout': textSummary(data, { indent: ' ', enableColors: true }),
  };
}

function textSummary(data, opts) {
  const metrics = data.metrics;
  const iterations = metrics.iterations ? metrics.iterations.values.count : 0;
  const successRegs = metrics.successful_registrations ? metrics.successful_registrations.values.count : 0;
  const failRegs = metrics.failed_registrations ? metrics.failed_registrations.values.count : 0;
  
  return `
=====================================
  Student Registration Summary
=====================================
  Total Iterations: ${iterations}
  Successful Registrations: ${successRegs}
  Failed Registrations: ${failRegs}
  Error Rate: ${(metrics.errors.values.rate * 100).toFixed(2)}%
  Avg Response Time: ${metrics.http_req_duration.values.avg.toFixed(2)}ms
=====================================
`;
}