import path from 'node:path';

export function normalizeRelPath(value) {
  return String(value || '')
    .trim()
    .replace(/\\/g, '/')
    .replace(/^\/+|\/+$/g, '');
}

export function folderNameOk(name) {
  return !!name && !name.includes('/') && name !== '.' && name !== '..';
}

export function safeJoin(base, rel) {
  const baseResolved = path.resolve(base);
  const normalized = path.normalize(rel).replace(/^(\.\.(\/|\\|$))+/, '');
  const full = path.resolve(baseResolved, normalized);
  if (full !== baseResolved && !full.startsWith(baseResolved + path.sep)) {
    throw new Error('invalid path');
  }
  return full;
}

export function basenameOf(rel) {
  const parts = normalizeRelPath(rel).split('/');
  return parts[parts.length - 1] || rel;
}

export function parentOf(rel) {
  const normalized = normalizeRelPath(rel);
  const idx = normalized.lastIndexOf('/');
  return idx >= 0 ? normalized.slice(0, idx) : '';
}

export function joinRel(parent, name) {
  const p = normalizeRelPath(parent);
  const n = normalizeRelPath(name);
  return p ? `${p}/${n}` : n;
}

export function isReservedName(ctx, name) {
  const base = basenameOf(name);
  return (
    [ctx.trashDirName, ctx.metaDirName, ctx.sessionDirName].includes(base)
    || base.startsWith('.drive-')
    || base.startsWith('.fds-')
  );
}

export function trashRoot(ctx) {
  return path.join(ctx.uploadDir, ctx.trashDirName);
}

export function metaFile(ctx) {
  return path.join(ctx.uploadDir, ctx.metaDirName, 'registry.json');
}

export function sessionRoot(ctx) {
  return path.join(ctx.uploadDir, ctx.sessionDirName);
}