1import { writeFileSync, readFileSync, unlinkSync, existsSync } from 'fs'
2import { ensurePtTmpDir, ptTmpDir } from '../../serverF/libFs/ensurePtTmpDirF.mts'
3
4const lockFile = `${ptTmpDir}/refactor.lock`
5const staleLockMs = 60_000
6
7type LockData = { pid: number, ts: number, op: string }
8
9const readLock = (): LockData | null => {
10  try { return JSON.parse(readFileSync(lockFile, 'utf8')) }
11  catch { return null }
12}
13
14const isPidAlive = (pid: number): boolean => {
15  try { process.kill(pid, 0); return true }
16  catch { return false }
17}
18
19export const acquireRefactorLock = (op: string) => {
20  const lock = readLock()
21  if (lock) {
22    const isStale = Date.now() - lock.ts > staleLockMs
23    const isDeadPid = !isPidAlive(lock.pid)
24    if (!isStale && !isDeadPid) {
25      const agoSec = Math.round((Date.now() - lock.ts) / 1000)
26      throw new Error(`Refactor lock held by pid ${lock.pid} (${lock.op}, ${agoSec}s ago). pt_mv must always be run sequentially never concurrently. Wait, then retry. DO NOT manually bypass pt_mv - imports will be missed.`)
27    }
28  }
29  ensurePtTmpDir()
30  writeFileSync(lockFile, JSON.stringify({ pid: process.pid, ts: Date.now(), op }))
31}
32
33export const releaseRefactorLock = () => {
34  const lock = readLock()
35  if (lock?.pid === process.pid) {
36    try { unlinkSync(lockFile) } catch {}
37  }
38}
39