// ledger.js

const fs = require('fs');
const path = require('path');

const LEDGER_DIR = path.join(__dirname, 'ledger');

function ensureLedgerDir() {
  if (!fs.existsSync(LEDGER_DIR)) {
    fs.mkdirSync(LEDGER_DIR);
  }
}

function timestampForFilename() {
  const now = new Date();
  const iso = now.toISOString(); // e.g. 2026-06-28T16:12:34.567Z
  return iso.replace(/[:.]/g, '-');
}

function writeLedgerEntry(entry) {
  ensureLedgerDir();

  const filename = `${timestampForFilename()}.json`;
  const filepath = path.join(LEDGER_DIR, filename);

  const payload = {
    engineVersion: 'v0.2-ledger',
    createdAt: new Date().toISOString(),
    entry,
  };

  fs.writeFileSync(filepath, JSON.stringify(payload, null, 2), 'utf8');

  return filepath;
}

module.exports = { writeLedgerEntry };