// Job-id deduplication. Recap mints a UUID per summarize job (the
// transcribe + analyze pair) and sends it in X-Recap-Job-Id on every
// relay call. The first call with a given (install_id, job_id) tuple
// reserves a credit; subsequent calls with the same tuple are free
// until the job_id expires (1 hour).
//
// Stored in-memory only — not persisted across restarts because (a)
// a restart breaks all in-flight Recap streams anyway and (b) the
// worst-case outcome of a "lost reservation" is the user being
// charged for a single retry, which is acceptable.

const JOB_TTL_MS = 60 * 60 * 1000; // 1 hour

// Map<install_id|job_id, { backend, tier, charged_at, refunded }>
const jobs = new Map();

function key(installId, jobId) {
  return `${installId}|${jobId}`;
}

// On a new request: returns { charged: true } if this is the first call
// for the job (caller must commit a credit), or { charged: false,
// backend, tier } if it's a retry/follow-up.
export function lookupJob(installId, jobId) {
  if (!installId || !jobId) return null;
  pruneExpired();
  const k = key(installId, jobId);
  const existing = jobs.get(k);
  if (existing && !existing.refunded) return existing;
  return null;
}

// Mark a job as having been charged. Idempotent — second call for the
// same (install_id, job_id) is a no-op.
export function markJobCharged(installId, jobId, { backend, tier }) {
  if (!installId || !jobId) return;
  pruneExpired();
  const k = key(installId, jobId);
  if (jobs.has(k) && !jobs.get(k).refunded) return;
  jobs.set(k, {
    backend,
    tier,
    charged_at: Date.now(),
    refunded: false,
  });
}

// Refund a previously charged credit for a failed job. Future calls
// with the same job_id will be treated as new (since the reservation
// is no longer valid).
export function refundJob(installId, jobId) {
  if (!installId || !jobId) return;
  const k = key(installId, jobId);
  const existing = jobs.get(k);
  if (existing) existing.refunded = true;
}

function pruneExpired() {
  const cutoff = Date.now() - JOB_TTL_MS;
  for (const [k, v] of jobs) {
    if (v.charged_at < cutoff) jobs.delete(k);
  }
}

export function snapshotJobs() {
  pruneExpired();
  return Array.from(jobs.entries()).map(([k, v]) => ({ key: k, ...v }));
}