.mode);
}

function handleTimestamps(srcMode, src, dest) {
  // Make sure the file is writable before setting the timestamp
  // otherwise open fails with EPERM when invoked with 'r+'
  // (through utimes call)
  if (fileIsNotWritable(srcMode)) makeFileWritable(dest, srcMode);
  return setDestTimestamps(src, dest);
}

function fileIsNotWritable(srcMode) {
  return (srcMode & 0o200) === 0;
}

function makeFileWritable(dest, srcMode) {
  return setDestMode(dest, srcMode | 0o200);
}

function setDestMode(dest, srcMode) {
  return chmodSync(dest, srcMode);
}

function setDestTimestamps(src, dest) {
  // The initial srcStat.atime cannot be trusted
  // because it is modified by the read(2) system call
  // (See https://nodejs.org/api/fs.html#fs_stat_time_values)
  const updatedSrcStat = statSync(src);
  return utimesSync(dest, updatedSrcStat.atime, updatedSrcStat.mtime);
}

// TODO(@anonrig): Move this function to C++.
function onDir(srcStat, destStat, src, dest, opts) {
  if (!destStat) return mkDirAndCopy(srcStat.mode, src, dest, opts);
  return copyDir(src, dest, opts);
}

function mkDirAndCopy(srcMode, src, dest, opts) {
  mkdirSync(dest);
  copyDir(src, dest, opts);
  return setDestMode(dest, srcMode);
}

// TODO(@anonrig): Move this function to C++.
function copyDir(src, dest, opts) {
  const dir = opendirSync(src);

  try {
    let dirent;

    while ((dirent = dir.readSync()) !== null) {
      const { name } = dirent;
      const srcItem = join(src, name);
      const destItem = join(dest, name);
      let shouldCopy = true;

      if (opts.filter) {
        shouldCopy = opts.filter(srcItem, destItem);
        if (isPromise(shouldCopy)) {
          throw new ERR_INVALID_RETURN_VALUE('boolean', 'filter', shouldCopy);
        }
      }

      if (shouldCopy) {
        getStats(srcItem, destItem, opts);
      }
    }
  } finally {
    dir.closeSync();
  }
}

// TODO(@anonrig): Move this function to C++.
function onLink(destStat, src, dest, verbatimSymlinks) {
  let resolvedSrc = readlinkSync(src);
  if (!verbatimSymlinks && !isAbsolute(resolvedSrc)) {
    resolvedSrc = resolve(dirname(src), resolvedSrc);
  }
  if (!destStat) {
    return symlinkSync(resolvedSrc, dest);
  }
  let resolvedDest;
  try {
    resolvedDest = readlinkSync(dest);
  } catch (err) {
    // Dest exists and is a regular file or directory,
    // Windows may throw UNKNOWN error. If dest already exists,
    // fs throws error anyway, so no need to guard against it here.
    if (err.code === 'EINVAL' || err.code === 'UNKNOWN') {
      return symlinkSync(resolvedSrc, dest);
    }
    throw err;
  }
  if (!isAbsolute(resolvedDest)) {
    resolvedDest = resolve(dirname(dest), resolvedDest);
  }
  if (isSrcSubdir(resolvedSrc, resolvedDest)) {
    throw new ERR_FS_CP_EINVAL({
      message: `cannot copy ${resolvedSrc} to a subdirectory of self ` +
          `${resolvedDest}`,
      path: dest,
      syscall: 'cp',
      errno: EINVAL,
      code: 'EINVAL',
    });
  }
  // Prevent copy if src is a subdir of dest since unlinking
  // dest in this case would result in removing src contents
  // and therefore a broken symlink would be created.
  if (statSync(dest).isDirectory() && isSrcSubdir(resolvedDest, resolvedSrc)) {
    throw new ERR_FS_CP_SYMLINK_TO_SUBDIRECTORY({
      message: `cannot overwrite ${resolvedDest} with ${resolvedSrc}`,
      path: dest,
      syscall: 'cp',
      errno: EINVAL,
      code: 'EINVAL',
    });
  }
  return copyLink(resolvedSrc, dest);
}

function copyLink(resolvedSrc, dest) {
  unlinkSync(dest);
  return symlinkSync(resolvedSrc, dest);
}

module.exports = { cpSyncFn };
