from operator import itemgetter
import socket
import prolog.engine
import prolog.util
from server.hints import Hint
import server.problems

id = 97
number = 5
visible = True
facts = 'family_relations'

solution = '''\
brother(X, Y) :-
  parent(P, X),
  parent(P, Y),
  male(X),
  X \== Y.
'''

hint_type = {
    'x_must_be_male': Hint('x_must_be_male'),
    'common_parent_needed': Hint('common_parent_needed'),
    'y_can_be_of_any_gender': Hint('y_can_be_of_any_gender'),
    'x_y_must_be_different': Hint('x_y_must_be_different'),
    'neq_used_too_early': Hint('neq_used_too_early'),
    'neq+_instead_of_neq': Hint('neq+_instead_of_neq'),
    'predicate_always_false': Hint('predicate_always_false'),
}

test_cases = [
    ('brother(X, _)',
        [{'X': 'alessandro'}, {'X': 'andrew'}, {'X': 'jeffrey'},
         {'X': 'kramer'}, {'X': 'michael'}, {'X': 'william'}]),
    ('brother(andrew, X)',
        [{'X': 'melanie'}]),
    ('brother(X, sally)',
        [{'X': 'jeffrey'}, {'X': 'william'}]),
]

def test(code, aux_code):
    n_correct = 0
    engine_id = None
    try:
        engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0)
        if engine_id is not None and 'error' not in map(itemgetter(0), output):
            # Engine successfully created, and no syntax error in program.
            for query, answers in test_cases:
                if prolog.engine.check_answers(engine_id, query=query, answers=answers, timeout=1.0):
                    n_correct += 1
    except socket.timeout:
        pass
    finally:
        if engine_id:
            prolog.engine.destroy(engine_id)

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

def hint(code, aux_code):
    tokens = prolog.util.tokenize(code)

    try:
        engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0)

        # use of \= or =\= instead of \==
        if prolog.util.Token('NEQU', '\=') in tokens or prolog.util.Token('NEQA', '=\=') in tokens:
            return [{'id': 'neq+_instead_of_neq'}]

        # target predicate seems to always be false
        if not prolog.engine.ask_truth(engine_id, 'brother(_, _)'):
            return [{'id': 'predicate_always_false'}]

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

        # X and Y must have a common parent
        if prolog.engine.ask_truth(engine_id,
            'brother(X, Y), \+ (parent(P, X), parent(P, Y))'):
            return [{'id': 'common_parent_needed'}]

        # Y can be of any gender, incl. female
        if prolog.engine.ask_truth(engine_id, 'brother(_, Y)') and \
           prolog.engine.ask_one(engine_id, 'brother(_, Y), female(Y)') == 'false':
            return [{'id': 'y_can_be_of_any_gender'}]

        # X and Y must be different
        if prolog.util.Token('NEQ', '\==') not in tokens and prolog.engine.ask_truth(engine_id,
            'setof(X, (member(X, [william, alessandro, andrew]), brother(X, X)), L), length(L, 3)'):
            return [{'id': 'x_y_must_be_different'}]

        # X and Y must be different, but \== was used
        if prolog.util.Token('NEQ', '\==') in tokens and prolog.engine.ask_truth(engine_id,
            'setof(X/Y, brother(X, Y), L), member(alessandro/alessandro, L), member(andrew/andrew, L), member(william/william, L)'):
            return [{'id': 'neq_used_too_early'}]

    except socket.timeout as ex:
        pass

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

    return []