"""Tests for the C header emitted from a TrustBundle."""

from cryptography.hazmat.primitives.asymmetric import ec

from aliro_harness.trustgen.header import TrustBundle, render_trust_header


def _bundle():
    return TrustBundle(
        issuer_public_key=ec.generate_private_key(ec.SECP256R1()).public_key(),
        reader_private_key=ec.generate_private_key(ec.SECP256R1()),
        reader_group_id=bytes(range(16)),
        reader_group_sub_id=bytes(range(16, 32)),
    )


def test_header_has_include_guard():
    text = render_trust_header(_bundle())
    assert "#ifndef ALIRO_TRUST_H_" in text
    assert "#define ALIRO_TRUST_H_" in text
    assert "#endif" in text


def test_header_marks_file_as_autogenerated():
    text = render_trust_header(_bundle())
    assert "AUTO-GENERATED" in text
    assert "DO NOT EDIT" in text


def test_header_defines_reader_private_key_as_32_bytes():
    text = render_trust_header(_bundle())
    assert "#define ALIRO_READER_PRIVATE_KEY" in text
    assert text.count("0x", text.index("ALIRO_READER_PRIVATE_KEY")) >= 32


def test_header_defines_reader_public_key_as_x_y_concatenated_64_bytes():
    text = render_trust_header(_bundle())
    assert "#define ALIRO_READER_PUBLIC_KEY" in text


def test_header_defines_issuer_pub_x_y_and_concatenated():
    text = render_trust_header(_bundle())
    assert "#define ALIRO_ISSUER_PUB_X" in text
    assert "#define ALIRO_ISSUER_PUB_Y" in text
    assert "#define ALIRO_ISSUER_PUB" in text


def test_header_defines_issuer_kid():
    text = render_trust_header(_bundle())
    assert "#define ALIRO_ISSUER_KID" in text


def test_header_defines_reader_group_ids():
    text = render_trust_header(_bundle())
    assert "#define ALIRO_READER_GROUP_ID" in text
    assert "#define ALIRO_READER_GROUP_SUB_ID" in text


def test_reader_private_key_bytes_match_input():
    bundle = _bundle()
    text = render_trust_header(bundle)

    expected = bundle.reader_private_key.private_numbers().private_value.to_bytes(32, "big")
    first_byte_hex = f"0x{expected[0]:02x}"
    last_byte_hex = f"0x{expected[-1]:02x}"

    priv_block_start = text.index("ALIRO_READER_PRIVATE_KEY")
    priv_block_end = text.index("#define", priv_block_start + 1)
    block = text[priv_block_start:priv_block_end]

    assert first_byte_hex in block
    assert last_byte_hex in block


def test_issuer_kid_matches_compute_issuer_kid():
    from aliro_harness.issuer.kid import compute_issuer_kid

    bundle = _bundle()
    text = render_trust_header(bundle)

    expected_kid = compute_issuer_kid(bundle.issuer_public_key)
    kid_start = text.index("ALIRO_ISSUER_KID")
    kid_end = text.index("\n", kid_start)
    kid_line = text[kid_start:kid_end]

    for b in expected_kid:
        assert f"0x{b:02x}" in kid_line