import { readFile, writeFile, chmod } from 'node:fs/promises';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';

const HERE = dirname(fileURLToPath(import.meta.url));
const REGISTRY_PATH = join(HERE, 'registry.json');

export async function loadRegistry() {
  try {
    const raw = await readFile(REGISTRY_PATH, 'utf8');
    const parsed = JSON.parse(raw);
    if (!parsed || typeof parsed !== 'object' || Array.isArray(parsed)) {
      return {};
    }
    return parsed;
  } catch {
    return {};
  }
}

export async function saveRegistry(registry) {
  const data = registry && typeof registry === 'object' ? registry : {};
  await writeFile(REGISTRY_PATH, JSON.stringify(data, null, 2) + '\n', { encoding: 'utf8', mode: 0o600 });
  try { await chmod(REGISTRY_PATH, 0o600); } catch {}
}

export async function upsertEntry(entry) {
  if (!entry || typeof entry.label !== 'string' || entry.label.length === 0) {
    throw new Error('upsertEntry: entry.label is required');
  }
  const registry = await loadRegistry();
  registry[entry.label] = {
    host: entry.host,
    port: entry.port,
    token: entry.token,
    fp: entry.fp,
    label: entry.label,
    version: entry.version,
    lastConnectedAt: entry.lastConnectedAt ?? new Date().toISOString(),
  };
  await saveRegistry(registry);
  return registry[entry.label];
}

export async function getEntry(label) {
  if (typeof label !== 'string' || label.length === 0) return null;
  const registry = await loadRegistry();
  return registry[label] ?? null;
}

export { REGISTRY_PATH };