"""Parser tests for the dependency-free resolver (no network)."""
import socket
import struct

from mdns_tools import _stdlib_resolve as sr


def _a_response(hostname: str, ips: list[str], ttl: int = 120) -> bytes:
    """Craft a minimal mDNS response with one question and N A answers."""
    header = struct.pack(">HHHHHH", 0, 0x8400, 1, len(ips), 0, 0)
    labels = b""
    for part in hostname.rstrip(".").split("."):
        labels += bytes([len(part)]) + part.encode()
    labels += b"\x00"
    question = labels + struct.pack(">HH", 1, 1)
    answers = b""
    for ip in ips:
        answers += labels + struct.pack(">HHIH", 1, 1, ttl, 4)
        answers += socket.inet_aton(ip)
    return header + question + answers


def test_build_query_roundtrip():
    q = sr.build_query("host.local", sr.QTYPE_A)
    # header is 12 bytes; QDCOUNT must be 1
    assert struct.unpack(">H", q[4:6])[0] == 1
    assert q.endswith(struct.pack(">HH", 1, 1))


def test_skip_name_plain():
    data = b"\x04host\x05local\x00rest"
    off = sr.skip_name(data, 0)
    assert data[off:off + 4] == b"rest"


def test_parse_all_a_single():
    resp = _a_response("dell.local", ["192.168.1.17"])
    recs = sr.parse_all_a(resp)
    assert recs == [("192.168.1.17", 120)]


def test_parse_all_a_multiple():
    resp = _a_response("multi.local", ["192.168.1.5", "192.168.122.1"])
    ips = [ip for ip, _ in sr.parse_all_a(resp)]
    assert ips == ["192.168.1.5", "192.168.122.1"]


def test_parse_all_a_empty_on_garbage():
    assert sr.parse_all_a(b"\x00\x00") == []