import pytest
from cq2_sdk.utils.encoding import encode6bit, decode6bit


def test_encode_empty():
    assert encode6bit(b"") == b""


def test_decode_empty():
    assert decode6bit(b"") == b""


def test_encode_ascii_produces_printable():
    # 3 input bytes -> 4 output bytes
    result = encode6bit(b"abc")
    assert isinstance(result, bytes)
    assert len(result) == 4
    # All output bytes should be printable ASCII (>= 0x3B offset means >= 0x3B)
    for b in result:
        assert 0x3B <= b <= 0x3B + 0x3F  # 0x3B to 0x7A


def test_roundtrip_3_bytes():
    original = b"abc"
    assert decode6bit(encode6bit(original)) == original


def test_roundtrip_typical_password():
    original = b"hello world 123 !@#"
    encoded = encode6bit(original)
    decoded = decode6bit(encoded)
    assert decoded == original


@pytest.mark.parametrize("inp", [
    b"a",
    b"ab",
    b"abcd",
    b"abcdef",
    b"a" * 100,
    b"\x00\xff\x7f\x80",
    bytes(range(256)),
])
def test_roundtrip_various_lengths(inp):
    encoded = encode6bit(inp)
    decoded = decode6bit(encoded)
    assert decoded == inp, f"failed for input of length {len(inp)}"


def test_encode_known_vector_abc():
    # Literal derived from the extracted substitution table and ARM64 codec.
    assert encode6bit(b"abc") == b"xK_H"