"""Pure, offline tests for the netfinder packet codec in progpib.discovery.

Fixture bytes are taken from sampledata.txt, a captured Python 3 REPL
session against real Prologix GPIB-ETHERNET hardware (all using the same
sequence number, 30327 = 0x7677, reused across the whole session).
"""

from progpib.discovery import (
    _HEADER_LEN,
    DeviceInfo,
    IpType,
    NfCommand,
    NfResult,
    _pack_assignment,
    _pack_header,
    _pack_identify,
    _unpack_assignment_reply,
    _unpack_identify_reply,
    _unpack_test_reply,
)

SEQ = 30327
MAC = b"\x00!i\x01-\xaf"


def test_pack_identify_matches_captured_bytes():
    assert _pack_identify(SEQ) == b"Z\x00vw\xff\xff\xff\xff\xff\xff\x00\x00"


def test_unpack_identify_reply_matches_captured_session():
    reply = (
        b"Z\x01vw\x00!i\x01-\xaf\x00\x00\x00%\x0572\x01\x00\x00\xc0\xa8\x00\xe5"
        b"\xff\xff\xff\x00\xc0\xa8\x00\x01\x01\x06\x06\x00\x01\x03\x00\x00"
        b"\x01\x03\x00\x00600" + b"\x00" * 29
    )
    assert len(reply) == 76
    info = _unpack_identify_reply(reply)

    assert info == DeviceInfo(
        mac=MAC,
        mode=1,
        alert=0,
        ip_type=IpType.DYNAMIC,
        ip_address="192.168.0.229",
        netmask="255.255.255.0",
        gateway="192.168.0.1",
        app_version="1.6.6.0",
        boot_version="1.3.0.0",
        hw_version="1.3.0.0",
        name="600",
        uptime_days=37,
        uptime_hours=5,
        uptime_minutes=55,
        uptime_seconds=50,
    )
    assert info.mac_str == "00:21:69:01:2d:af"


def test_pack_assignment_matches_captured_bytes():
    # This regression-pins the chr()->bytes([...]) fix: vendortools/nfutil.py's
    # MkAssignment raises struct.error on this exact call (see sampledata.txt),
    # since struct.pack's 'c' format needs a length-1 bytes object, not chr()'s str.
    packet = _pack_assignment(
        SEQ,
        MAC,
        IpType.DYNAMIC,
        "192.168.0.229",
        "255.255.255.0",
        "192.168.0.1",
    )
    expected = (
        b"Z\x02vw\x00!i\x01-\xaf\x00\x00\x00\x00\x00\x00\xc0\xa8\x00\xe5"
        b"\xff\xff\xff\x00\xc0\xa8\x00\x01" + b"\x00" * 32
    )
    assert len(expected) == 60
    assert packet == expected


def test_unpack_assignment_reply_matches_captured_bytes():
    # This datagram is captured mid-session in sampledata.txt as a reply to
    # an earlier Assignment request (both used seq 30327): header id 0x03 =
    # ASSIGNMENT_REPLY, followed by a single 0x00 result byte = NF_SUCCESS.
    reply = b"Z\x03vw\x00!i\x01-\xaf\x00\x00\x00\x00\x00\x00"
    assert _unpack_assignment_reply(reply) == NfResult.SUCCESS


def test_pack_and_unpack_test_reply_roundtrip():
    # sampledata.txt has no clean captured TestReply (the byte string shown
    # there after a MkTest() call is actually a stale AssignmentReply still
    # sitting in the receive socket's buffer from an earlier command in that
    # REPL session -- see test_unpack_assignment_reply_matches_captured_bytes
    # above). So this is a synthetic round-trip instead of a captured fixture.
    text = "Prologix GPIB-ETHERNET Sim 1.0"
    body = text.encode("ascii").ljust(32, b"\x00")
    reply = _pack_header(NfCommand.TEST_REPLY, SEQ, MAC) + body
    assert len(reply) == _HEADER_LEN + 32
    assert _unpack_test_reply(reply) == text