/**
 * @file One-step rotation for AgentHub's append-only runtime logs (server.log,
 * bootstrap.log, client-build.log, plugin-update.log, cc-update-all.log): a
 * file past `max` bytes becomes `<file>.1`, replacing the previous one, so
 * each log costs at most twice `max` however long the install lives. Pure fs,
 * never throws — a log must never stop what it records.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
"use strict";

const fs = require("fs");

const DEFAULT_MAX = 5 * 1024 * 1024;

function rotateIfLarge(file, max = DEFAULT_MAX) {
  try {
    if (fs.statSync(file).size > max) fs.renameSync(file, `${file}.1`);
  } catch {
    /* missing file, or not ours to move: keep appending */
  }
}

module.exports = { rotateIfLarge, DEFAULT_MAX };

if (require.main === module) {
  // Self-check: node scripts/log-rotate.js
  const os = require("os");
  const path = require("path");
  const assert = require("assert");
  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "log-rotate-"));
  const f = path.join(dir, "x.log");
  fs.writeFileSync(f, "a".repeat(20));
  rotateIfLarge(f, 10);
  assert.ok(!fs.existsSync(f) && fs.statSync(`${f}.1`).size === 20);
  fs.writeFileSync(f, "b".repeat(5));
  rotateIfLarge(f, 10);
  assert.equal(fs.readFileSync(f, "utf8"), "bbbbb");
  rotateIfLarge(path.join(dir, "missing.log"), 10);
  fs.rmSync(dir, { recursive: true, force: true });
  console.log("log-rotate ok");
}