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

const BASE_URL = __ENV.BASE_URL || 'http://localhost:8080';
const TENANT_HEADER = __ENV.TENANT_HEADER || 'X-StellaOps-Tenant';
const TENANTS = (__ENV.TENANTS || 'tenant-a,tenant-b,tenant-c,tenant-d,tenant-e,tenant-f,tenant-g,tenant-h,tenant-i,tenant-j')
  .split(',')
  .map((t) => t.trim())
  .filter(Boolean);
const READ_PATHS = (__ENV.TENANT_READ_PATHS || '/api/v1/policy/effective,/api/v1/vuln/search?limit=50,/notify/api/v1/events?limit=20,/health/readiness')
  .split(',')
  .map((p) => p.trim())
  .filter(Boolean);
const WRITE_PATHS = (__ENV.TENANT_WRITE_PATHS || '/api/v1/policy/evaluate,/notify/api/v1/test,/api/v1/tasks/submit')
  .split(',')
  .map((p) => p.trim())
  .filter(Boolean);

const READ_FRACTION = Number(__ENV.READ_FRACTION || '0.9');
const SLEEP_MS = Number(__ENV.SLEEP_MS || '250');
let seed = Number(__ENV.SEED || '1');

function rnd() {
  seed = (seed * 1664525 + 1013904223) >>> 0;
  return seed / 4294967296;
}

export const options = {
  vus: Number(__ENV.VUS || '250'),
  duration: __ENV.DURATION || '10m',
  thresholds: {
    http_req_failed: ['rate<0.005'],
    http_req_duration: ['p(95)<300'],
    'tenant_write_duration': ['p(95)<600'],
    'tenant_auth_failures': ['rate<0.01'],
  },
};

const readDuration = new Trend('tenant_read_duration', true);
const writeDuration = new Trend('tenant_write_duration', true);
const authFailures = new Rate('tenant_auth_failures');

function pick(list) {
  return list[Math.floor(rnd() * list.length)];
}

export default function () {
  const tenant = pick(TENANTS);
  const doWrite = rnd() > READ_FRACTION;
  const path = doWrite ? pick(WRITE_PATHS) : pick(READ_PATHS);

  const headers = {
    [TENANT_HEADER]: tenant,
    'Content-Type': 'application/json',
  };

  const url = `${BASE_URL}${path}`;
  const payload = JSON.stringify({
    tenant,
    traceId: __VU + '-' + Date.now(),
    now: new Date().toISOString(),
    sample: 'tenant-chaos',
  });

  const params = { headers, tags: { tenant, path, kind: doWrite ? 'write' : 'read' } };
  const res = doWrite ? http.post(url, payload, params) : http.get(url, params);

  if (!check(res, {
    'status ok': (r) => r.status >= 200 && r.status < 300,
  })) {
    if (res.status === 401 || res.status === 403) {
      authFailures.add(1);
    }
  }

  if (doWrite) {
    writeDuration.add(res.timings.duration);
  } else {
    readDuration.add(res.timings.duration);
  }

  sleep(SLEEP_MS / 1000);
}