from core.public_params import PublicParams
from core.participant import Participant


def check_case(prime_modulus, generator, x, y, K_expected):
    """
    Строит участников, имитирует обмен и проверяет совпадение ключа с эталоном.
    Возвращает: ok (bool), (A, B, K_a, K_b)
    """
    params = PublicParams(prime_modulus, generator)
    alice = Participant(params, secret=x)
    bob = Participant(params, secret=y)

    A = alice.public_value
    B = bob.public_value

    K_a = alice.compute_shared_key(B)
    K_b = bob.compute_shared_key(A)

    ok = (K_a == K_b == K_expected)
    return ok, (A, B, K_a, K_b)