// The Studio's runs on the job service, without a browser or a service: a
// job whose answer is lost is sent again under its key to a service that
// keeps keys, and sent once, with no key, to one that does not; a poll whose
// answer is lost does not end the wait.
//
//   node test/service.test.mjs
import { ServiceEngine } from '../src/engine.js';

let fails = 0;
const check = (ok, what) => { console.log(`${ok ? 'PASS' : 'FAIL'}  ${what}`); if (!ok) fails += 1; };

// A service from a script: each answer is a status and a body, or 'drop'
// for a connection that ends before its answer. Every request is kept.
function service(script) {
  const seen = [];
  globalThis.fetch = async (url, init = {}) => {
    const path = new URL(url).pathname;
    seen.push({ method: init.method || 'GET', path, headers: init.headers || {} });
    const queue = script[`${init.method || 'GET'} ${path}`] ?? [];
    const next = queue.length > 1 ? queue.shift() : queue[0];
    if (next === undefined) return new Response(JSON.stringify({ error: `no answer for ${path}` }), { status: 500 });
    if (next === 'drop') throw new TypeError('Failed to fetch');
    return new Response(JSON.stringify(next[1]), { status: next[0], headers: { 'content-type': 'application/json' } });
  };
  return seen;
}

const base = 'https://jobs.example/quantum-jobs';
const done = { id: 'j1', status: 'done', result: { counts: { '00': 5, '11': 5 } } };
const keeps = { idempotency: { header: 'Idempotency-Key', on: ['POST /v1/jobs', 'POST /v1/run'] } };

{
  const seen = service({
    'GET /quantum-jobs/v1': [[200, keeps]],
    'POST /quantum-jobs/v1/jobs': ['drop', [202, { id: 'j1', status: 'queued' }]],
    'GET /quantum-jobs/v1/jobs/j1': [[200, done]],
  });
  const job = await new ServiceEngine(base).run({ qasm: 'OPENQASM 3.0; qubit q;', shots: 10 });
  const posts = seen.filter((r) => r.method === 'POST');
  const keys = posts.map((r) => r.headers['idempotency-key']);
  check(job.status === 'done' && job.id === 'j1', 'the job whose answer was lost ends done');
  check(posts.length === 2 && keys[0] && keys[0] === keys[1], `sent again under the same key (${keys.join(', ')})`);
  check(/^[0-9a-f-]{32,36}$/.test(keys[0]), 'the key is a random UUID');
}

{
  const seen = service({
    'GET /quantum-jobs/v1': [[200, { service: 'wai-quantum-service' }]],
    'POST /quantum-jobs/v1/jobs': ['drop'],
  });
  let err = null;
  try { await new ServiceEngine(base).run({ qasm: 'OPENQASM 3.0; qubit q;' }); } catch (e) { err = e; }
  const posts = seen.filter((r) => r.method === 'POST');
  check(err && posts.length === 1, 'a service that keeps no keys is sent the job once');
  check(!('idempotency-key' in posts[0].headers), 'and no key, which its CORS would refuse');
}

{
  const seen = service({
    'GET /quantum-jobs/v1': [[200, keeps]],
    'POST /quantum-jobs/v1/jobs': [[202, { id: 'j1', status: 'queued' }]],
    'GET /quantum-jobs/v1/jobs/j1': ['drop', [200, { id: 'j1', status: 'running' }], [200, done]],
  });
  const e = new ServiceEngine(base);
  const job = await e.run({ qasm: 'OPENQASM 3.0; qubit q;' });
  check(job.status === 'done', 'a poll whose answer is lost does not end the wait');
  await e.run({ qasm: 'OPENQASM 3.0; qubit q;' });
  check(seen.filter((r) => r.path === '/quantum-jobs/v1').length === 1, 'the service is asked once whether it keeps keys');
}

{
  service({
    'GET /quantum-jobs/v1': [[200, keeps]],
    'POST /quantum-jobs/v1/jobs': [[202, { id: 'j1', status: 'queued' }]],
    'GET /quantum-jobs/v1/jobs/j1': ['drop'],
  });
  let err = null;
  try { await new ServiceEngine(base).run({ qasm: 'OPENQASM 3.0; qubit q;' }); } catch (e) { err = e; }
  check(err !== null, 'five lost polls in a row end the wait');
}

console.log(fails ? `${fails} failed` : 'service: every check passed');
process.exit(fails ? 1 : 0);