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

const BASE_URL = __ENV.BASE_URL || 'http://app:3000';
const seed = JSON.parse(open('./seed-data.json'));

const writeFailures = new Counter('write_failures');

export const options = {
  stages: [
    { duration: '20s', target: 50 },
    { duration: '20s', target: 100 },
    { duration: '30s', target: 150 },
    { duration: '30s', target: 200 },
    { duration: '30s', target: 250 },
    { duration: '30s', target: 300 },
    { duration: '30s', target: 350 },
    { duration: '30s', target: 400 },
    { duration: '30s', target: 450 },
    { duration: '30s', target: 500 },
    { duration: '30s', target: 550 },
    { duration: '30s', target: 600 },
    { duration: '20s', target: 0 },
  ],
  thresholds: {
    http_req_failed: ['rate<0.02'],
    http_req_duration: ['p(95)<500'],
    write_failures: ['count==0'],
  },
};

export default function () {
  const unique = `${__VU}-${__ITER}-${Date.now()}`;
  const startTime = new Date(Date.now() + 60 * 60 * 1000);
  const endTime = new Date(startTime.getTime() + 30 * 60 * 1000);

  // 1. Insert a new user
  const userResponse = http.post(
    `${BASE_URL}/users/`,
    JSON.stringify({
      fullName: `Load Test ${unique}`,
      email: `load-${unique}@example.invalid`,
      phone: `9${String(__VU).padStart(1, '0')}${String(__ITER).padStart(8, '0')}`.slice(0, 10),
    }),
    { headers: { 'Content-Type': 'application/json' }, tags: { name: 'POST /users' } }
  );

  const userOk = check(userResponse, {
    'user inserted (201)': (r) => r.status === 201,
  });

  if (!userOk) {
    writeFailures.add(1);
    return;
  }

  const userId = userResponse.json('result._id');

  // 2. Insert a session for the existing seeded teacher
  const sessionResponse = http.post(
    `${BASE_URL}/sessions/`,
    JSON.stringify({
      teacherId: seed.teacher.id,
      startTime: startTime.toISOString(),
      endTime: endTime.toISOString(),
    }),
    { headers: { 'Content-Type': 'application/json' }, tags: { name: 'POST /sessions' } }
  );

  const sessionOk = check(sessionResponse, {
    'session inserted (201)': (r) => r.status === 201,
  });

  if (!sessionOk) {
    writeFailures.add(1);
    return;
  }

  const sessionId = sessionResponse.json('result._id');

  // 3. Book the newly created session
  const bookingResponse = http.post(
    `${BASE_URL}/sessions/${sessionId}/book`,
    JSON.stringify({ userId }),
    { headers: { 'Content-Type': 'application/json' }, tags: { name: 'POST /sessions/:id/book' } }
  );

  const bookingOk = check(bookingResponse, {
    'session booked (200)': (r) => r.status === 200,
  });

  if (!bookingOk) {
    writeFailures.add(1);
    return;
  }

  // 4. Complete the booked session
  const completeResponse = http.patch(
    `${BASE_URL}/sessions/${sessionId}/complete`,
    null,
    { tags: { name: 'PATCH /sessions/:id/complete' } }
  );

  const completeOk = check(completeResponse, {
    'session completed (200)': (r) => r.status === 200,
  });

  if (!completeOk) {
    writeFailures.add(1);
    return;
  }

  // 5. Read user session history
  const historyResponse = http.get(
    `${BASE_URL}/sessions/${userId}/sessions`,
    { tags: { name: 'GET /sessions/:userId/sessions' } }
  );

  check(historyResponse, {
    'user history returned (200)': (r) => r.status === 200,
  });

  sleep(1);
}

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