"""Canonical encoding: the byte layer every other guarantee depends on."""

from fablepool.canonical import canonical_encode, sha256_hex


def test_returns_bytes():
    assert isinstance(canonical_encode({}), (bytes, bytearray))


def test_empty_containers():
    assert bytes(canonical_encode({})) == b"{}"
    assert bytes(canonical_encode([])) == b"[]"


def test_key_order_independence():
    a = canonical_encode({"a": 1, "b": 2, "c": [1, 2]})
    b = canonical_encode({"c": [1, 2], "b": 2, "a": 1})
    assert bytes(a) == bytes(b)


def test_keys_sorted_in_output():
    assert bytes(canonical_encode({"b": 2, "a": 1})) == b'{"a":1,"b":2}'


def test_keys_sorted_by_code_point():
    # "Z" (0x5A) sorts before "a" (0x61): byte order, not locale order.
    assert bytes(canonical_encode({"a": 1, "Z": 2})) == b'{"Z":2,"a":1}'


def test_nested_objects_sorted():
    out = bytes(canonical_encode({"outer": {"b": [3, 2, 1], "a": "x"}}))
    assert out == b'{"outer":{"a":"x","b":[3,2,1]}}'


def test_array_order_preserved():
    out = bytes(canonical_encode(["b", "a", 2, 1]))
    assert out == b'["b","a",2,1]'


def test_no_insignificant_whitespace():
    out = bytes(canonical_encode({"a": [1, 2], "b": {"c": 3}}))
    assert b" " not in out
    assert b"\n" not in out


def test_unicode_emitted_raw_not_escaped():
    out = bytes(canonical_encode({"k": "é"}))
    assert out == '{"k":"é"}'.encode("utf-8")
    assert b"\\u" not in out


def test_deterministic_across_calls():
    value = {"z": None, "a": True, "nested": {"k": ["v", 1]}}
    assert bytes(canonical_encode(value)) == bytes(canonical_encode(value))


def test_sha256_known_vectors():
    # FIPS 180-4 reference digests.
    assert (
        sha256_hex(b"")
        == "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
    )
    assert (
        sha256_hex(b"abc")
        == "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"
    )