# coding=utf-8

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

id = 110
number = 17
visible = True
facts = None

solution = '''\
dup([], []).
dup([H|T], [H,H|TT]) :-
  dup(T, TT).
'''

test_cases = [
    ('dup([], X)',
        [{'X': '[]'}]),
    ('dup([y], X)',
        [{'X': '[y, y]'}]),
    ('dup([k, f, f, g, a], X)',
        [{'X': '[k, k, f, f, f, f, g, g, a, a]'}]),
    ('dup(X, [k, k, f, f, f, f, g, g, a, a])',
        [{'X': '[k, f, f, g, a]'}]),
]

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

    n_correct = 0
    engine_id = None
    try:
        engine_id, output = prolog.engine.create(code=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:
                # 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 []