# utility to match command-line args to names


class Candidates:

    def __init__(self, names):
        self.names = names
    # is an input string acceptable for one of the known names?

    @staticmethod
    def fits(input, name):
        return name.find(input) == 0
    # returns one of the names if the input name has a unique match
    # or None otherwise

    def only_match(self, input):
        if input in self.names:
            return input
        matches = [name for name in self.names if Candidates.fits(input, name)]
        if len(matches) == 1:
            return matches[0]
        else:
            return None

# minimal test
candidates_specs = [
    ('create delete reset resources slices start status stop version create_gid',
     [('ver', 'version'),
      ('r', None),
         ('re', None),
         ('res', None),
         ('rese', 'reset'),
         ('reset', 'reset'),
         ('reso', 'resources'),
         ('sli', 'slices'),
         ('st', None),
         ('sta', None),
         ('stop', 'stop'),
         ('a', None),
         ('cre', None),
         ('create', 'create'),
         ('create_', 'create_gid'),
         ('create_g', 'create_gid'),
         ('create_gi', 'create_gid'),
         ('create_gid', 'create_gid'),
      ])
]


def test_candidates():
    for (names, tuples) in candidates_specs:
        names = names.split()
        for (input, expected) in tuples:
            got = Candidates(names).only_match(input)
            if got == expected:
                print('.', end=' ')
            else:
                print('X FAIL', 'names[', names, '] input',
                      input, 'expected', expected, 'got', got)

if __name__ == '__main__':
    test_candidates()