const fs = require("node:fs/promises");
const { randomUUID } = require("node:crypto");

async function writeOutput(file, contents, io = fs) {
  try {
    if (await io.readFile(file, "utf8") === contents) return;
  } catch (error) {
    if (error.code !== "ENOENT") throw error;
  }
  // Replace a complete file; never remove or truncate a script the browser may load.
  const temporary = `${file}.${randomUUID()}.tmp`;
  try {
    await io.writeFile(temporary, contents, { encoding: "utf8", flag: "wx" });
    await io.rename(temporary, file);
  } finally {
    await io.rm(temporary, { force: true });
  }
}

module.exports = { writeOutput };