import { open, rename, unlink } from "node:fs/promises";
import { dirname, join } from "node:path";
import { randomUUID } from "node:crypto";

async function syncDirectory(path: string): Promise<void> {
  const directory = await open(path, "r");
  try {
    await directory.sync();
  } finally {
    await directory.close();
  }
}

export async function writeFileAtomically(path: string, content: string): Promise<void> {
  const directory = dirname(path);
  const temporary = join(directory, `.${randomUUID()}.tmp`);
  const file = await open(temporary, "wx", 0o600);
  try {
    await file.writeFile(content, "utf8");
    await file.sync();
  } catch (error) {
    await file.close();
    await unlink(temporary).catch(() => undefined);
    throw error;
  }
  await file.close();

  try {
    await rename(temporary, path);
    await syncDirectory(directory);
  } catch (error) {
    await unlink(temporary).catch(() => undefined);
    throw error;
  }
}