/** Per-host token bucket + concurrency gate. In-process; the worker runs one process per node so this is sufficient. */
interface Bucket { tokens: number; last: number; rpm: number; inflight: number; concurrency: number; waiters: Array<() => void> }
const buckets = new Map<string, Bucket>();

export function configureHost(host: string, rpm: number, concurrency: number): void {
  const b = buckets.get(host) ?? { tokens: rpm, last: Date.now(), rpm, inflight: 0, concurrency, waiters: [] };
  b.rpm = rpm; b.concurrency = concurrency;
  buckets.set(host, b);
}

export async function acquire(host: string, minDelayMs = 0): Promise<() => void> {
  const b = buckets.get(host) ?? (buckets.set(host, { tokens: 30, last: Date.now(), rpm: 30, inflight: 0, concurrency: 2, waiters: [] }), buckets.get(host)!);
  for (;;) {
    const now = Date.now();
    b.tokens = Math.min(b.rpm, b.tokens + ((now - b.last) / 60_000) * b.rpm);
    b.last = now;
    if (b.tokens >= 1 && b.inflight < b.concurrency) { b.tokens -= 1; b.inflight += 1; break; }
    const wait = b.tokens < 1 ? Math.ceil(((1 - b.tokens) / b.rpm) * 60_000) : 50;
    await new Promise((r) => setTimeout(r, Math.max(25, Math.min(wait, 5000), minDelayMs)));
  }
  if (minDelayMs > 0) await new Promise((r) => setTimeout(r, minDelayMs));
  let released = false;
  return () => { if (!released) { released = true; b.inflight -= 1; } };
}

export function hostStats(): Record<string, { rpm: number; inflight: number; tokens: number }> {
  const out: Record<string, { rpm: number; inflight: number; tokens: number }> = {};
  for (const [h, b] of buckets) out[h] = { rpm: b.rpm, inflight: b.inflight, tokens: Math.round(b.tokens) };
  return out;
}