import os


def get_server_root_dir(settings):
    # notebook >= 5.0.0 has this in the settings
    if 'server_root_dir' in settings:
        return settings['server_root_dir']

    # This copies the logic added in the notebook in
    #  https://github.com/jupyter/notebook/pull/2234
    contents_manager = settings['contents_manager']
    root_dir = contents_manager.root_dir
    home = os.path.expanduser('~')
    if root_dir.startswith(home + os.path.sep):
        # collapse $HOME to ~
        root_dir = '~' + root_dir[len(home):]
    return root_dir