'''Utility functions for xauth.'''
import os
import hashlib

from easyprocess import EasyProcess


class NotFoundError(Exception):
    '''Error when xauth was not found.'''
    pass


def is_installed():
    '''
    Return whether or not xauth is installed.
    '''
    try:
        p = EasyProcess(['xauth', '-V'])
        p.enable_stdout_log = False
        p.enable_stderr_log = False
        p.call()
    except Exception:
        return False
    else:
        return True


def generate_mcookie():
    '''
    Generate a cookie string suitable for xauth.
    '''
    data = os.urandom(16)  # 16 bytes = 128 bit
    return hashlib.md5(data).hexdigest()


def call(*args):
    '''
    Call xauth with the given args.
    '''
    EasyProcess(['xauth'] + list(args)).call()
