/**
 * Stress test: 500 req/s target on critical endpoints (v0.951)
 * Endpoints: login, get tracks, search, marketplace products
 * Usage: k6 run loadtests/backend/stress_500rps.js
 * Output: k6 run --out json=report.json loadtests/backend/stress_500rps.js
 */
import http from 'k6/http';
import { check, sleep } from 'k6';
import { randomString } from 'https://jslib.k6.io/k6-utils/1.2.0/index.js';

const BASE_URL = __ENV.BASE_URL || __ENV.API_ORIGIN || 'http://localhost:8080';
const TEST_EMAIL_PREFIX = __ENV.TEST_EMAIL_PREFIX || 'user+stress';
const TEST_EMAIL_DOMAIN = __ENV.TEST_EMAIL_DOMAIN || 'example.com';
const TEST_PASSWORD_PREFIX = __ENV.TEST_PASSWORD_PREFIX || 'V3za!stress-';

function generateTestUser() {
  const rand = randomString(8);
  const pwd = `${TEST_PASSWORD_PREFIX}${rand}`;
  return {
    email: `${TEST_EMAIL_PREFIX}${rand}@${TEST_EMAIL_DOMAIN}`,
    password: pwd,
    password_confirmation: pwd,
    username: `st${rand}`,
  };
}

export const options = {
  scenarios: {
    stress: {
      executor: 'ramping-vus',
      stages: [
        { duration: '1m', target: 100 },
        { duration: '1m', target: 250 },
        { duration: '1m', target: 500 },
        { duration: '2m', target: 500 },
        { duration: '30s', target: 0 },
      ],
      gracefulRampDown: '20s',
      exec: 'stressScenario',
    },
  },
  thresholds: {
    'http_req_duration{name:login}': ['p(99)<500'],
    'http_req_duration{name:tracks}': ['p(99)<500'],
    'http_req_duration{name:search}': ['p(99)<500'],
    'http_req_duration{name:products}': ['p(99)<500'],
    http_req_duration: ['p(50)<100', 'p(95)<300', 'p(99)<500'],
    http_req_failed: ['rate<0.05'],
  },
};

export function setup() {
  const users = [];
  const baseURL = `${BASE_URL}/api/v1/auth`;
  for (let i = 0; i < 100; i++) {
    const user = generateTestUser();
    const registerRes = http.post(`${baseURL}/register`, JSON.stringify(user), {
      headers: { 'Content-Type': 'application/json' },
    });
    if (registerRes.status === 201) {
      const loginRes = http.post(`${baseURL}/login`, JSON.stringify({ email: user.email, password: user.password }), {
        headers: { 'Content-Type': 'application/json' },
      });
      if (loginRes.status === 200) {
        try {
          const body = JSON.parse(loginRes.body);
          const token = body.data?.token?.access_token;
          if (token) users.push({ ...user, token });
        } catch (e) {}
      }
    }
  }
  return { users };
}

export function stressScenario(data) {
  const { users } = data;
  const baseURL = `${BASE_URL}/api/v1`;
  const action = Math.floor(Math.random() * 4);

  if (action === 0 && users.length > 0) {
    const user = users[Math.floor(Math.random() * users.length)];
    const res = http.post(
      `${baseURL}/auth/login`,
      JSON.stringify({ email: user.email, password: user.password }),
      {
        headers: { 'Content-Type': 'application/json' },
        tags: { name: 'login' },
      }
    );
    check(res, { 'login 200': (r) => r.status === 200 });
  } else if (action === 1) {
    const headers = users.length > 0
      ? { Authorization: `Bearer ${users[Math.floor(Math.random() * users.length)].token}` }
      : {};
    const res = http.get(`${baseURL}/tracks?limit=20`, { headers, tags: { name: 'tracks' } });
    check(res, { 'tracks 200 or 401': (r) => r.status === 200 || r.status === 401 });
  } else if (action === 2) {
    const headers = users.length > 0
      ? { Authorization: `Bearer ${users[Math.floor(Math.random() * users.length)].token}` }
      : {};
    const q = ['test', 'music', 'beat', 'track', 'audio'][Math.floor(Math.random() * 5)];
    const res = http.get(`${baseURL}/tracks/search?q=${q}&limit=10`, { headers, tags: { name: 'search' } });
    check(res, { 'search 200 or 401': (r) => r.status === 200 || r.status === 401 });
  } else {
    const res = http.get(`${baseURL}/marketplace/products`, { tags: { name: 'products' } });
    check(res, { 'products 200': (r) => r.status === 200 });
  }

  sleep(0.1);
}