from ex2a_skeleton import *


def xor_then_decrypt_bit(
    cipher_pair1: Tuple[int, int],
    cipher_pair2: Tuple[int, int],
    s: int = 19,
    q: int = 97,
):
    """
    Xor Cipher pairs and then decrypt a bit using Learning with errors.

    :param cipher_pair1: First cipher pair (u, v)
    :param cipher_pair2: Second cipher pair (u, v)
    :param s: Secret key
    :param q: Modulus

        TODO 1: Compute the "dec" value with which you will decrypt the bit.
            dec = ((v_1 - s * u_1) + (v_2 - s * u_2)) % q

        TODO 2: Obtain and return the decrypted bit.
            The decrypted bit is 1 if the previously computed "dec" value is bigger than floor(q/2) and 0 otherwise.

    :return the decrypted bit
    """

    # Extract pair (u, v) from the argument "cipher_pair".
    u_1 = cipher_pair1[0]
    v_1 = cipher_pair1[1]

    u_2 = cipher_pair2[0]
    v_2 = cipher_pair2[1]

    # TODO 1: Compute "dec" variable

    # TODO 2: Decrypt bit and return it


def xor_then_decrypt(
    cipher1: List[Tuple[int, int]],
    cipher2: List[Tuple[int, int]],
    s: int = 19,
    q: int = 97,
) -> List[int]:
    """
    Bit wise xor the two cipher pairs and the decrypt 4-bit number result.

    :param cipher1: Cipher 1.
    :param cipher2: Cipher 2.
    :param s: Secret key
    :param q: Modulus

    :return plain: List with the 4 decrypted bits.
    """
    u1_1, v1_1 = cipher1[0][0], cipher1[0][1]
    u2_1, v2_1 = cipher1[1][0], cipher1[1][1]
    u3_1, v3_1 = cipher1[2][0], cipher1[2][1]
    u4_1, v4_1 = cipher1[3][0], cipher1[3][1]

    u1_2, v1_2 = cipher2[0][0], cipher2[0][1]
    u2_2, v2_2 = cipher2[1][0], cipher2[1][1]
    u3_2, v3_2 = cipher2[2][0], cipher2[2][1]
    u4_2, v4_2 = cipher2[3][0], cipher2[3][1]

    bit0 = xor_then_decrypt_bit((u1_1, v1_1), (u1_2, v1_2), s, q)
    bit1 = xor_then_decrypt_bit((u2_1, v2_1), (u2_2, v2_2), s, q)
    bit2 = xor_then_decrypt_bit((u3_1, v3_1), (u3_2, v3_2), s, q)
    bit3 = xor_then_decrypt_bit((u4_1, v4_1), (u4_2, v4_2), s, q)

    return [bit3, bit2, bit1, bit0]


def main() -> None:
    # TODO 3: Test it on some examples to see if is working properly
    ...


if __name__ == "__main__":
    main()