const fs = require('fs/promises');
const path = require('path');
const { randomUUID } = require('crypto');

async function ensureDir(dirPath) {
  await fs.mkdir(dirPath, { recursive: true });
}

async function readJson(filePath) {
  const raw = await fs.readFile(filePath, 'utf8');
  return JSON.parse(raw);
}

async function readJsonIfExists(filePath) {
  if (!(await fileExists(filePath))) {
    return null;
  }

  return readJson(filePath);
}

async function writeJson(filePath, value) {
  await ensureDir(path.dirname(filePath));
  const tempPath = `${filePath}.${randomUUID()}.tmp`;
  await fs.writeFile(tempPath, JSON.stringify(value, null, 2));
  await fs.rename(tempPath, filePath);
}

async function fileExists(filePath) {
  try {
    await fs.access(filePath);
    return true;
  } catch (error) {
    return false;
  }
}

async function listJsonFiles(dirPath) {
  await ensureDir(dirPath);
  const entries = await fs.readdir(dirPath, { withFileTypes: true });

  return entries
    .filter((entry) => entry.isFile() && entry.name.endsWith('.json'))
    .map((entry) => path.join(dirPath, entry.name))
    .sort();
}

async function appendJsonLine(filePath, value) {
  await ensureDir(path.dirname(filePath));
  await fs.appendFile(filePath, `${JSON.stringify(value)}\n`);
}

async function moveFile(fromPath, toPath) {
  await ensureDir(path.dirname(toPath));
  await fs.rename(fromPath, toPath);
}

async function removeFile(filePath) {
  await fs.rm(filePath, { force: true });
}

module.exports = {
  ensureDir,
  readJson,
  readJsonIfExists,
  writeJson,
  fileExists,
  listJsonFiles,
  appendJsonLine,
  moveFile,
  removeFile,
};