import { link, mkdir, open, rename, rm } from 'node:fs/promises'
import { randomUUID } from 'node:crypto'
import { dirname } from 'node:path'

async function syncDirectory(path) {
  const handle = await open(path, 'r')
  try {
    await handle.sync()
  } finally {
    await handle.close()
  }
}

async function temporaryFile(path, bytes, mode) {
  await mkdir(dirname(path), { recursive: true })
  const temporary = `${path}.${randomUUID()}.tmp`
  const handle = await open(temporary, 'wx', mode)
  try {
    await handle.writeFile(bytes)
    await handle.sync()
  } finally {
    await handle.close()
  }
  return temporary
}

export async function durableReplace(path, bytes, mode = 0o600) {
  const temporary = await temporaryFile(path, bytes, mode)
  try {
    await rename(temporary, path)
    await syncDirectory(dirname(path))
  } catch (error) {
    await rm(temporary, { force: true })
    throw error
  }
}

export async function durableCreate(path, bytes, mode = 0o600) {
  const temporary = await temporaryFile(path, bytes, mode)
  try {
    await link(temporary, path)
    await syncDirectory(dirname(path))
  } finally {
    await rm(temporary, { force: true })
  }
}