import fs from 'fs';
import path from 'path';
import mime from 'mime';
import { DATA_DIR as RAW_DATA_DIR } from '../../config.js';

// Resolve DATA_DIR once, ensure absolute path and normalized with trailing separator for prefix checks
const DATA_DIR = path.resolve(RAW_DATA_DIR);
const DATA_DIR_WITH_SEP = DATA_DIR.endsWith(path.sep) ? DATA_DIR : DATA_DIR + path.sep;

export function resolveSafePath(name) {
  if (!name || typeof name !== 'string') return null;
  // Prevent path traversal and normalize input
  const joined = path.join(DATA_DIR, name);
  const resolved = path.resolve(joined);
  if (resolved === DATA_DIR || resolved.startsWith(DATA_DIR_WITH_SEP)) return resolved;
  return null;
}

export function fileExists(p) {
  try {
    return fs.existsSync(p);
  } catch {
    return false;
  }
}

export function statFile(p) {
  return fs.statSync(p);
}

export function getMimeType(p, fallback = 'audio/mpeg') {
  return mime.getType(p) || fallback;
}