/**
 * Per-node identity keys for orchestrator-managed children.
 *
 * A hosted node joins the cadre whose owner claimed it: the claim named its peer
 * id, and the owner's phone dials the addresses keyed to that peer id. Both bind
 * to the identity, so a node that generated a fresh libp2p keypair per process
 * would become a stranger to the cadre that claimed it on every restart. It also
 * needs a stable on-disk home for its node-local stores — `cadre-cli start`
 * opens `FileBootstrapPeerStore` / `FileTrustedOwnerStore` /
 * `FileStrandNetworkStateStore` in the node's state directory, which defaults to
 * the directory holding the config file the orchestrator writes into the workdir.
 *
 * So every managed node gets its own `identity.key` inside its workdir, written
 * once and reused thereafter. The workdir is removed with the node
 * (`removeContainer`), so nothing the node persisted outlives it.
 */

import { existsSync } from 'node:fs';
import { join } from 'node:path';

import { generateIdentity, loadIdentity, type IdentityRecord } from './identity-file.js';

const IDENTITY_FILE = 'identity.key';

/** Path to a managed node's own protobuf identity key inside its workdir. */
export function nodeIdentityPath(workdir: string): string {
  return join(workdir, IDENTITY_FILE);
}

/**
 * Ensure `<workdir>/identity.key` exists, generating an Ed25519 protobuf key on
 * first call and REUSING it on every later call. Reuse is the load-bearing
 * property: a re-spawn of the same container must land on the same peer id.
 */
export async function ensureNodeIdentity(workdir: string): Promise<{ path: string; peerId: string }> {
  const path = nodeIdentityPath(workdir);
  const record: IdentityRecord = existsSync(path)
    ? loadIdentity(path)
    : await generateIdentity(path);
  return { path, peerId: record.peerId };
}