class UI(object):
    def __init__(self, verbose=False, quiet=False, debug=False,
                 traceback=False):
        self.quiet = quiet and not (verbose or debug)
        self.verbose = verbose or debug
        self.debug = debug
        self.traceback = traceback

    def write(self, *messages):
        for m in messages:
            sys.stdout.write(m)

    def write_err(self, *messages):
        for m in messages:
            sys.stderr.write(m)

    status = lambda self, *m: not self.quiet and self.write(*m)
    note = lambda self, *m: self.verbose and self.write(*m)
    warn = lambda self, *m: self.write_err(*m)
    debug = lambda self, *m: self.debug and self.write(*m)

    def abort(self, message):
        raise Abort(message)

    def print_exc(self):
        if self.traceback:
            traceback.print_exc()
        return self.traceback

    def _readline(self, message=''):
        try:
            import readline
            readline.read_history_file
        except Exception:
            # windows can raise something other than ImportError
            pass
        line = raw_input(message)
        # When stdin is in binary mode on Windows, it can cause
        # raw_input() to emit an extra trailing carriage return
        if os.linesep == '\r\n' and line and line[-1] == '\r':
            line = line[:-1]
        return line

    def prompt(self, message, pattern=None, default="y"):
        while True:
            try:
                inp = self._readline(message + ' ')
                if not inp and default:
                    return default
                if not pattern or re.match(pattern, inp):
                    return inp
                else:
                    self.write('unrecognized response\n')
            except EOFError:
                self.abort('response excepted')