# coding=utf-8

id = 98
group = 'family_relations'
number = 5
visible = True
facts = 'family_relations'

solution = '''\
sister98(X, Y) :-
  parent(P, X),
  parent(P, Y),
  female(X),
  X \== Y.

aunt(X, Y) :-
  sister98(X, Z),
  parent(Z, Y).
'''

hint_type = {
    'x_and_y_mixed_up': Hint('x_and_y_mixed_up'),
    'precedence_fail': Hint('precedence_fail'),
    'x_must_be_female': Hint('x_must_be_female'),
    'aunt_vs_mother': Hint('aunt_vs_mother'),
    'x_need_not_be_parent': Hint('x_need_not_be_parent'),
    'y_need_not_be_parent': Hint('y_need_not_be_parent'),
}

test_cases = [
    # TODO
]

def test(program, solved_problems):
    code = (program + '\n' +
            server.problems.solutions_for_problems('prolog', solved_problems) + '\n' +
            server.problems.load_facts('prolog', facts).facts)

    engine_id = None
    try:
        engine_id, output = prolog.engine.create(code=code, timeout=1.0)
        if not engine_id or 'error' in map(itemgetter(0), output):
            # Engine creation failed, or syntax error in code.
            return 0, len(test_cases)

        n_correct = 0
        for query, answers in test_cases:
            # Limit inferences for each solution to curb unbounded recursion.
            limited = 'call_with_inference_limit(({}), 100000, _)'.format(query)
            if prolog.engine.check_answers(engine_id, query=limited, answers=answers, timeout=1.0):
                n_correct += 1
    finally:
        if engine_id:
            prolog.engine.destroy(engine_id)

    passed = n_correct == len(test_cases)
    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_cases)}}]
    return passed, hints

def hint(program, solved_problems):
    tokens = prolog.util.tokenize(program)

    code = (program + '\n' +
            server.problems.solutions_for_problems('prolog', solved_problems) + '\n' +
            server.problems.load_facts('prolog', facts).facts)

    engine_id = None
    try:
        engine_id, output = prolog.engine.create(code=code, timeout=1.0)
        if not engine_id:
            raise Exception('Prolog engine failed to create.')

        # X and Y mixed up
        # warning: knowledge base dependent
        # independent: match on findall(X/Y, (sister(Y, P), parent(P, X)), L)
        if prolog.engine.ask_truth(engine_id,
            'findall(X/Y, aunt(X, Y), \
             [vanessa/sally, patricia/sally, joanne/melanie, john/vanessa, susan/patricia])'):
            return [{'id', 'x_and_y_mixed_up'}]

        # precedence fail (AND block vs OR block)
        # case in point: female(X), parent(P, Y), brother(P, X) ; sister(P, X)
        # warning: knowledge base dependent
        if prolog.util.Token('SEMI', ';') in tokens and prolog.engine.ask_truth(engine_id,
            'findall(_, aunt(X, Y), L), length(L, 15)'):
            return [{'id', 'precedence_fail'}]

        # X must be female
        if prolog.engine.ask_truth(engine_id,
            'aunt(X, _), male(X)'):
            return [{'id', 'x_must_be_female'}]

        # X and P can be the same person
        # this can occur if the problem is not solved using sister/2
        if prolog.engine.ask_truth(engine_id,
            'aunt(X, Y), mother(X, Y)'):
            return [{'id', 'aunt_vs_mother'}]

        # X does not necessarily need to be a parent
        # perhaps risky as only one aunt that is not a parent exists in DB (melanie)
        if prolog.engine.ask_one(engine_id,
            'aunt(X, _), \+ parent(X, _)') == 'false':
            return [{'id': 'x_need_not_be_parent'}]

        # Y does not necessarily need to be a parent
        # perhaps risky as only one such nephew exists in DB (susan)
        if prolog.engine.ask_one(engine_id,
            'aunt(_, Y), \+ parent(Y, _)') == 'false':
            return [{'id': 'y_need_not_be_parent'}]

    except socket.timeout as ex:
        pass

    finally:
        if engine_id:
            prolog.engine.destroy(engine_id)

    return None