import struct

import pytest
from app.dmx.backends import (
    ARTNET_HEADER,
    ARTNET_OPCODE_DMX,
    ARTNET_OPCODE_POLL_REPLY,
    ARTNET_PORT,
    ArtNetDmxBackend,
    build_artnet_dmx_packet,
    parse_artnet_poll_reply,
)
from app.dmx.frame import DmxFrame


def test_build_artnet_packet_sends_full_512_frame_to_expected_universe() -> None:
    values = [0] * 512
    values[0] = 255
    values[9] = 64
    packet = build_artnet_dmx_packet(2, values, sequence=9)

    assert packet.startswith(ARTNET_HEADER)
    assert struct.unpack_from("<H", packet, 8)[0] == ARTNET_OPCODE_DMX
    assert packet[12] == 9
    assert packet[14] == 1
    assert packet[15] == 0
    assert struct.unpack_from(">H", packet, 16)[0] == 512
    assert len(packet) == 530
    assert packet[18] == 255
    assert packet[27] == 64


def test_parse_artnet_poll_reply_extracts_node_identity() -> None:
    packet = bytearray(239)
    packet[0:8] = ARTNET_HEADER
    struct.pack_into("<H", packet, 8, ARTNET_OPCODE_POLL_REPLY)
    packet[10:14] = bytes([192, 168, 2, 55])
    packet[18] = 0
    packet[19] = 1
    packet[26 : 26 + len(b"WLED Node\x00")] = b"WLED Node\x00"
    packet[44 : 44 + len(b"Paravega Test Node\x00")] = b"Paravega Test Node\x00"
    struct.pack_into(">H", packet, 172, 4)
    packet[190] = 3

    node = parse_artnet_poll_reply(bytes(packet))

    assert node is not None
    assert node.ip == "192.168.2.55"
    assert node.short_name == "WLED Node"
    assert node.long_name == "Paravega Test Node"
    assert node.port_count == 4
    assert node.raw_port_address == 3
    assert node.label == "Paravega Test Node (192.168.2.55)"


@pytest.mark.asyncio
async def test_artnet_backend_sends_udp_packet_and_updates_status(monkeypatch) -> None:
    sent_packets: list[tuple[bytes, tuple[str, int]]] = []

    class FakeSocket:
        def setsockopt(self, *_args: object) -> None:
            return

        def sendto(self, packet: bytes, address: tuple[str, int]) -> None:
            sent_packets.append((packet, address))

        def close(self) -> None:
            return

    backend = ArtNetDmxBackend(
        universe=4,
        target_host="192.168.2.77",
        output_port="Paravega stue",
    )
    monkeypatch.setattr(backend, "_socket", FakeSocket())
    frame = DmxFrame(universe=4)
    frame.set_channel(1, 200, "scene")
    frame.set_channel(4, 99, "scene")

    await backend.send_frame(frame)

    status = backend.get_status()
    assert status.connected is True
    assert status.degraded is False
    assert status.frames_sent == 1
    assert status.send_errors == 0
    assert status.selected_universe == 4
    assert status.selected_output_port == "Paravega stue"
    assert sent_packets[0][1] == ("192.168.2.77", ARTNET_PORT)
    assert sent_packets[0][0][18] == 200
    assert sent_packets[0][0][21] == 99


@pytest.mark.asyncio
async def test_artnet_backend_marks_degraded_on_socket_error(monkeypatch) -> None:
    class FakeSocket:
        def setsockopt(self, *_args: object) -> None:
            return

        def sendto(self, _packet: bytes, _address: tuple[str, int]) -> None:
            raise OSError("Network unreachable")

        def close(self) -> None:
            return

    backend = ArtNetDmxBackend(universe=1, target_host="192.168.2.90")
    monkeypatch.setattr(backend, "_socket", FakeSocket())
    frame = DmxFrame()
    frame.set_channel(1, 255, "scene")

    with pytest.raises(RuntimeError, match="Network unreachable"):
        await backend.send_frame(frame)

    status = backend.get_status()
    assert status.connected is False
    assert status.degraded is True
    assert status.send_errors == 1
    assert status.last_error == "Network unreachable"