from pm3py.core.protocol import crc16_a, crc15, crc15_bytes

def test_crc16_a_empty():
    assert crc16_a(b"") == 0x6363  # init 0xC6C6 reflected = 0x6363

def test_crc16_a_known_vector():
    # Verified against C implementation: compute_crc(CRC_14443_A, ...)
    # "123456789" is the standard CRC check string
    data = b"123456789"
    assert crc16_a(data) == 0xBF05

def test_crc16_a_ping_preamble():
    # A CMD_PING preamble: magic=0x61334d50, length|ng=0x8020, cmd=0x0109
    preamble = bytes.fromhex("504d3361208001090102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f")
    crc = crc16_a(preamble)
    assert isinstance(crc, int)
    assert 0 <= crc <= 0xFFFF


def test_crc15_known_vector():
    # ISO15693 / NFC Type 5 CRC == CRC-16/X-25; standard check string -> 0x906E
    assert crc15(b"123456789") == 0x906E

def test_crc15_residue():
    # Appending crc15 (LSB-first) then re-running the raw X-25 loop over the full
    # frame yields the X-25 residue 0xF0B8 — the property firmware CheckCrc15 uses.
    data = bytes([0x26, 0x01, 0x00])
    frame = data + crc15_bytes(data)
    crc = 0xFFFF
    for byte in frame:
        crc ^= byte
        for _ in range(8):
            crc = (crc >> 1) ^ 0x8408 if (crc & 1) else (crc >> 1)
    assert crc == 0xF0B8