# coding=utf-8

from operator import itemgetter
import prolog.engine
import server.problems

id = 104
number = 12
visible = True
facts = None

solution = '''\
conc([], L, L).
conc([H|T], L2, [H|L]) :-
  conc(T, L2, L).
'''

test_cases = [
    ('conc([j,b], [l], X)',
        [{'X': '[j, b, l]'}]),
    ('conc([a,r,u,e], [c,f], X)',
        [{'X': '[a, r, u, e, c, f]'}]),
    ('conc(X, [], [g,r])',
        [{'X': '[g, r]'}]),
    ('conc([], [], [])',
        [{}]),
]

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

    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):
    # TODO
    return []