"""Test discovery of Ubiquiti airOS devices."""

import asyncio
from collections.abc import Callable
import os
import socket
from typing import Any, cast
from unittest.mock import AsyncMock, MagicMock, patch

import pytest

from airos.discovery import (
    DISCOVERY_PORT,
    AirOSDiscoveryProtocol,
    airos_discover_devices,
)
from airos.exceptions import AirOSDiscoveryError, AirOSEndpointError, AirOSListenerError

# pylint: disable=redefined-outer-name


# Helper to load binary fixture
async def _read_binary_fixture(fixture_name: str) -> bytes:
    """Read a binary fixture file."""
    fixture_dir = os.path.join(os.path.dirname(__file__), "../fixtures")
    path = os.path.join(fixture_dir, fixture_name)
    try:

        def _read_file() -> bytes:
            """Read the fixture file."""
            with open(path, "rb") as f:
                return f.read()

        return await asyncio.to_thread(_read_file)
    except FileNotFoundError:
        pytest.fail(f"Fixture file not found: {path}")
    except OSError as e:
        pytest.fail(f"Error reading fixture file {path}: {e}")


@pytest.fixture
async def mock_airos_packet() -> bytes:
    """Fixture for a valid airos discovery packet with scrubbed data."""
    return await _read_binary_fixture("airos_sta_discovery_packet.bin")


@pytest.mark.asyncio
async def test_parse_airos_packet_success(mock_airos_packet: bytes) -> None:
    """Test parse_airos_packet with a valid packet containing scrubbed data."""
    protocol = AirOSDiscoveryProtocol(
        AsyncMock()
    )  # Callback won't be called directly in this unit test
    host_ip = (
        "192.168.1.3"  # The IP address from the packet sender (as per scrubbed data)
    )

    # Directly call the parsing method
    parsed_data = protocol.parse_airos_packet(mock_airos_packet, host_ip)

    assert parsed_data is not None
    assert parsed_data["ip_address"] == "192.168.1.3"
    assert parsed_data["mac_address"] == "01:23:45:67:89:CD"  # Expected scrubbed MAC
    assert parsed_data["hostname"] == "name"  # Expected scrubbed hostname
    assert parsed_data["model"] == "NanoStation 5AC loco"
    assert parsed_data["firmware_version"] == "WA.V8.7.17"
    assert parsed_data["uptime_seconds"] == 265375
    assert parsed_data["ssid"] == "DemoSSID"
    assert parsed_data["full_model_name"] == "NanoStation 5AC loco"


@pytest.mark.asyncio
async def test_parse_airos_packet_invalid_header() -> None:
    """Test parse_airos_packet with an invalid header."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    invalid_data = b"\x00\x00\x00\x00\x00\x00" + b"someotherdata"
    host_ip = "192.168.1.100"

    # Patch the _LOGGER.debug to verify the log message
    with patch("airos.discovery._LOGGER.debug") as mock_log_debug:
        with pytest.raises(AirOSEndpointError):
            protocol.parse_airos_packet(invalid_data, host_ip)
        mock_log_debug.assert_called_once()
        assert (
            "does not start with expected AirOS header"
            in mock_log_debug.call_args[0][0]
        )


@pytest.mark.asyncio
async def test_parse_airos_packet_too_short() -> None:
    """Test parse_airos_packet with data too short for header."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    too_short_data = b"\x01\x06\x00"
    host_ip = "192.168.1.100"

    # Patch the _LOGGER.debug to verify the log message
    with patch("airos.discovery._LOGGER.debug") as mock_log_debug:
        with pytest.raises(AirOSEndpointError):
            protocol.parse_airos_packet(too_short_data, host_ip)
        mock_log_debug.assert_called_once()
        assert (
            "Packet too short for initial fixed header"
            in mock_log_debug.call_args[0][0]
        )


@pytest.mark.asyncio
async def test_parse_airos_packet_truncated_tlv() -> None:
    """Test parse_airos_packet with a truncated TLV."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    # Header + MAC TLV (valid) + then a truncated TLV_IP
    truncated_data = (
        b"\x01\x06\x00\x00\x00\x00"  # Header
        b"\x06"
        + bytes.fromhex("0123456789CD")  # Valid MAC (scrubbed)
        + b"\x02\x00"  # TLV type 0x02, followed by only 1 byte for length (should be 2)
    )
    host_ip = "192.168.1.100"

    # Expect AirOSEndpointError due to struct.error or IndexError
    with pytest.raises(AirOSEndpointError):
        protocol.parse_airos_packet(truncated_data, host_ip)


@pytest.mark.asyncio
async def test_datagram_received_calls_callback(mock_airos_packet: bytes) -> None:
    """Test that datagram_received correctly calls the callback."""
    mock_callback = AsyncMock()
    protocol = AirOSDiscoveryProtocol(mock_callback)
    host_ip = "192.168.1.3"  # Sender IP

    with patch("asyncio.create_task") as mock_create_task:
        protocol.datagram_received(mock_airos_packet, (host_ip, DISCOVERY_PORT))

        # Verify the task was created and get the coroutine
        mock_create_task.assert_called_once()
        task_coro = mock_create_task.call_args[0][0]

        # Manually await the coroutine to test the callback
        await task_coro

    mock_callback.assert_called_once()
    called_args, _ = mock_callback.call_args
    parsed_data = called_args[0]
    assert parsed_data["ip_address"] == "192.168.1.3"
    assert parsed_data["mac_address"] == "01:23:45:67:89:CD"  # Verify scrubbed MAC


@pytest.mark.asyncio
async def test_datagram_received_handles_parsing_error() -> None:
    """Test datagram_received handles exceptions during parsing."""
    mock_callback = AsyncMock()
    protocol = AirOSDiscoveryProtocol(mock_callback)
    invalid_data = b"\x00\x00"  # Too short, will cause parsing error
    host_ip = "192.168.1.100"

    with patch("airos.discovery._LOGGER.exception") as mock_log_exception:
        # datagram_received catches errors internally and re-raises AirOSDiscoveryError
        with pytest.raises(AirOSDiscoveryError):
            protocol.datagram_received(invalid_data, (host_ip, DISCOVERY_PORT))
        mock_callback.assert_not_called()
        mock_log_exception.assert_called_once()  # Ensure exception is logged


@pytest.mark.asyncio
async def test_connection_made_sets_transport() -> None:
    """Test connection_made sets up transport and socket options."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    mock_transport = MagicMock(spec=asyncio.DatagramTransport)
    mock_sock = MagicMock(spec=socket.socket)  # Corrected: socket import added
    mock_transport.get_extra_info.return_value = mock_sock

    with patch("airos.discovery._LOGGER.debug") as mock_log_debug:
        protocol.connection_made(mock_transport)

        assert protocol.transport is mock_transport
        mock_sock.setsockopt.assert_any_call(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
        mock_sock.setsockopt.assert_any_call(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        mock_log_debug.assert_called_once()


@pytest.mark.asyncio
async def test_connection_lost_without_exception() -> None:
    """Test connection_lost without an exception."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    with patch("airos.discovery._LOGGER.debug") as mock_log_debug:
        protocol.connection_lost(None)
        mock_log_debug.assert_called_once_with(
            "AirOSDiscoveryProtocol connection lost."
        )


@pytest.mark.asyncio
async def test_connection_lost_with_exception() -> None:
    """Test connection_lost with an exception."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    test_exception = Exception("Test connection lost error")
    with (
        patch("airos.discovery._LOGGER.error") as mock_log_error,
        pytest.raises(AirOSDiscoveryError),
    ):
        protocol.connection_lost(test_exception)
    mock_log_error.assert_called_once()


@pytest.mark.asyncio
async def test_error_received() -> None:
    """Test error_received logs the error."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    test_exception = Exception("Test network error")
    with patch("airos.discovery._LOGGER.error") as mock_log_error:
        protocol.error_received(test_exception)
        mock_log_error.assert_called_once_with(
            f"UDP error received in AirOSDiscoveryProtocol: {test_exception}"
        )


# Front-end discovery tests


@pytest.mark.asyncio
async def test_async_discover_devices_success(
    mock_airos_packet: bytes,
    mock_datagram_endpoint: tuple[asyncio.DatagramTransport, AirOSDiscoveryProtocol],
) -> None:
    """Test the high-level discovery function on a successful run."""
    mock_transport, mock_protocol_instance = mock_datagram_endpoint

    discovered_devices = {}

    def mock_protocol_factory(callback: Callable[[Any], None]) -> MagicMock:
        def inner_callback(device_info: dict[str, Any]) -> None:
            """Inner callback to process discovered device info."""
            mac_address = device_info.get("mac_address")
            if mac_address:
                discovered_devices[mac_address] = device_info

        return MagicMock(callback=inner_callback)

    with patch(
        "airos.discovery.AirOSDiscoveryProtocol",
        new=MagicMock(side_effect=mock_protocol_factory),
    ):

        async def _simulate_discovery() -> None:
            """Simulate the discovery process by sending a mock packet."""
            await asyncio.sleep(0.1)

            protocol = AirOSDiscoveryProtocol(
                MagicMock()
            )  # Create a real protocol instance just for parsing
            parsed_data = protocol.parse_airos_packet(mock_airos_packet, "192.168.1.3")

            mock_protocol_factory(MagicMock()).callback(parsed_data)

        with patch("airos.discovery.asyncio.sleep", new=AsyncMock()):
            discovery_task = asyncio.create_task(airos_discover_devices(timeout=1))

            await _simulate_discovery()

            await discovery_task

    assert "01:23:45:67:89:CD" in discovered_devices
    assert discovered_devices["01:23:45:67:89:CD"]["hostname"] == "name"
    close_mock = cast(MagicMock, mock_transport.close)
    close_mock.assert_called_once()


@pytest.mark.asyncio
async def test_async_discover_devices_no_devices(
    mock_datagram_endpoint: tuple[asyncio.DatagramTransport, AirOSDiscoveryProtocol],
) -> None:
    """Test discovery returns an empty dict if no devices are found."""
    mock_transport, _ = mock_datagram_endpoint

    with patch("airos.discovery.asyncio.sleep", new=AsyncMock()):
        result = await airos_discover_devices(timeout=1)

    assert result == {}
    close_mock = cast(MagicMock, mock_transport.close)
    close_mock.assert_called_once()


@pytest.mark.asyncio
async def test_async_discover_devices_oserror(
    mock_datagram_endpoint: tuple[asyncio.DatagramTransport, AirOSDiscoveryProtocol],
) -> None:
    """Test discovery handles OSError during endpoint creation."""
    mock_transport, _ = mock_datagram_endpoint

    with patch("asyncio.get_running_loop") as mock_get_loop:
        mock_loop = mock_get_loop.return_value
        mock_loop.create_datagram_endpoint = AsyncMock(
            side_effect=OSError(98, "Address in use")
        )

        with pytest.raises(AirOSEndpointError) as excinfo:
            await airos_discover_devices(timeout=1)

    assert "address_in_use" in str(excinfo.value)
    close_mock = cast(MagicMock, mock_transport.close)
    close_mock.assert_not_called()


@pytest.mark.asyncio
async def test_async_discover_devices_cancelled(
    mock_datagram_endpoint: tuple[asyncio.DatagramTransport, AirOSDiscoveryProtocol],
) -> None:
    """Test discovery handles CancelledError during the timeout."""
    mock_transport, _ = mock_datagram_endpoint

    # Patch asyncio.sleep to immediately raise CancelledError
    with (
        patch("asyncio.sleep", new=AsyncMock(side_effect=asyncio.CancelledError)),
        pytest.raises(AirOSListenerError) as excinfo,
    ):
        await airos_discover_devices(timeout=1)

    assert "cannot_connect" in str(excinfo.value)
    close_mock = cast(MagicMock, mock_transport.close)
    close_mock.assert_called_once()


@pytest.mark.asyncio
async def test_datagram_received_handles_general_exception() -> None:
    """Test datagram_received handles a generic exception during parsing."""
    mock_callback = AsyncMock()
    protocol = AirOSDiscoveryProtocol(mock_callback)
    some_data = b"\x01\x06\x00\x00\x00\x00"
    host_ip = "192.168.1.100"

    with (
        patch.object(
            protocol, "parse_airos_packet", side_effect=ValueError("A generic error")
        ) as mock_parse,
        patch("airos.discovery._LOGGER.exception") as mock_log_exception,
    ):
        # A generic exception should be caught and re-raised as AirOSDiscoveryError
        with pytest.raises(AirOSDiscoveryError):
            protocol.datagram_received(some_data, (host_ip, DISCOVERY_PORT))

        mock_parse.assert_called_once_with(some_data, host_ip)
        mock_callback.assert_not_called()
        mock_log_exception.assert_called_once()
        assert (
            "Error processing AirOS discovery packet"
            in mock_log_exception.call_args[0][0]
        )


@pytest.mark.parametrize(
    ("packet_fragment", "error_message"),
    [
        # Case 1: TLV type 0x0A (Uptime) with wrong length
        (b"\x0a\x00\x02\x01\x02", "Unexpected length for Uptime (Type 0x0A)"),
        # Case 2: TLV declared length exceeds remaining packet data
        (b"\x0c\x00\xff\x41\x42", "length 255 exceeds remaining data"),
        # Case 3: An unknown TLV type
        (b"\xff\x01\x02", "Unhandled TLV type: 0xff"),
    ],
)
@pytest.mark.asyncio
async def test_parse_airos_packet_tlv_edge_cases(
    packet_fragment: bytes, error_message: str
) -> None:
    """Test parsing of various malformed TLV entries."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    # A valid header is required to get to the TLV parsing stage
    base_packet = b"\x01\x06\x00\x00\x00\x00"
    malformed_packet = base_packet + packet_fragment
    host_ip = "192.168.1.100"

    with pytest.raises(AirOSEndpointError) as excinfo:
        protocol.parse_airos_packet(malformed_packet, host_ip)

    assert error_message in str(excinfo.value)


@pytest.mark.asyncio
async def test_async_discover_devices_generic_oserror(
    mock_datagram_endpoint: tuple[asyncio.DatagramTransport, AirOSDiscoveryProtocol],
) -> None:
    """Test discovery handles a generic OSError during endpoint creation."""
    mock_transport, _ = mock_datagram_endpoint

    with patch("asyncio.get_running_loop") as mock_get_loop:
        mock_loop = mock_get_loop.return_value
        # Simulate an OSError that is NOT 'address in use'
        mock_loop.create_datagram_endpoint = AsyncMock(
            side_effect=OSError(13, "Permission denied")
        )
        with pytest.raises(AirOSEndpointError) as excinfo:
            await airos_discover_devices(timeout=1)

    assert "cannot_connect" in str(excinfo.value)
    close_mock = cast(MagicMock, mock_transport.close)
    close_mock.assert_not_called()


@pytest.mark.asyncio
async def test_parse_airos_packet_short_for_next_tlv() -> None:
    """Test parsing stops gracefully after the MAC TLV when no more data exists."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    # Header + valid MAC TLV, but then abruptly ends
    data_with_fragment = (
        b"\x01\x06\x00\x00\x00\x00" + b"\x06" + bytes.fromhex("0123456789CD")
    )
    host_ip = "192.168.1.100"

    with patch("airos.discovery._LOGGER.debug") as mock_log_debug:
        parsed_data = protocol.parse_airos_packet(data_with_fragment, host_ip)

        assert parsed_data is not None
        assert parsed_data["mac_address"] == "01:23:45:67:89:CD"
        # The debug log for the successfully parsed MAC address should be called exactly once.
        mock_log_debug.assert_called_once_with(
            "Parsed MAC from type 0x06: 01:23:45:67:89:CD"
        )


@pytest.mark.asyncio
async def test_parse_airos_packet_truncated_two_byte_tlv() -> None:
    """Test parsing with a truncated 2-byte length field TLV."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    # Header + valid MAC TLV, then a valid type (0x0a) but a truncated length field
    data_with_fragment = (
        b"\x01\x06\x00\x00\x00\x00"
        b"\x06"
        + bytes.fromhex("0123456789CD")
        + b"\x0a\x00"  # TLV type 0x0a, followed by only 1 byte for length (should be 2)
    )
    host_ip = "192.168.1.100"

    with patch("airos.discovery._LOGGER.warning") as mock_log_warning:
        with pytest.raises(AirOSEndpointError):
            protocol.parse_airos_packet(data_with_fragment, host_ip)

        mock_log_warning.assert_called_once()
        assert "no 2-byte length field" in mock_log_warning.call_args[0][0]


@pytest.mark.asyncio
async def test_parse_airos_packet_malformed_tlv_length() -> None:
    """Test parsing with a malformed TLV length field."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())
    # Header + valid MAC TLV, then a valid type (0x02) but a truncated length field
    data_with_fragment = (
        b"\x01\x06\x00\x00\x00\x00"
        b"\x06"
        + bytes.fromhex("0123456789CD")
        + b"\x02\x00"  # TLV type 0x02, followed by only 1 byte for length (should be 2)
    )
    host_ip = "192.168.1.100"

    with patch("airos.discovery._LOGGER.warning") as mock_log_warning:
        with pytest.raises(AirOSEndpointError):
            protocol.parse_airos_packet(data_with_fragment, host_ip)

        mock_log_warning.assert_called_once()
        assert "no 2-byte length field" in mock_log_warning.call_args[0][0]


@pytest.mark.parametrize(
    ("packet_fragment", "unhandled_type"),
    [
        (b"\x0e\x00\x02\x01\x02", "0xe"),  # Unhandled 2-byte length TLV
        (b"\x10\x00\x02\x01\x02", "0x10"),  # Unhandled 2-byte length TLV
    ],
)
@pytest.mark.asyncio
async def test_parse_airos_packet_unhandled_tlv_continues_parsing(
    packet_fragment: bytes, unhandled_type: str
) -> None:
    """Test that the parser logs an unhandled TLV type but continues parsing the packet."""
    protocol = AirOSDiscoveryProtocol(AsyncMock())

    # Construct a packet with a valid MAC TLV followed by the unhandled TLV
    valid_mac_tlv = b"\x06" + bytes.fromhex("0123456789CD")
    base_packet = b"\x01\x06\x00\x00\x00\x00"

    # This new packet structure ensures two TLVs are present
    malformed_packet = base_packet + valid_mac_tlv + packet_fragment
    host_ip = "192.168.1.100"

    with patch("airos.discovery._LOGGER.debug") as mock_log_debug:
        parsed_data = protocol.parse_airos_packet(malformed_packet, host_ip)

        assert parsed_data is not None
        assert parsed_data["mac_address"] == "01:23:45:67:89:CD"

        # Now, two debug logs are expected: one for the MAC and one for the unhandled TLV.
        assert mock_log_debug.call_count == 2

        # Check the first log call for the MAC address
        assert (
            mock_log_debug.call_args_list[0][0][0]
            == "Parsed MAC from type 0x06: 01:23:45:67:89:CD"
        )

        # Check the second log call for the unhandled TLV
        log_message = mock_log_debug.call_args_list[1][0][0]
        assert f"Unhandled TLV type: {unhandled_type}" in log_message
        assert "with length" in log_message


@pytest.mark.asyncio
async def test_async_discover_devices_generic_exception(
    mock_datagram_endpoint: tuple[asyncio.DatagramTransport, AirOSDiscoveryProtocol],
) -> None:
    """Test discovery handles a generic exception during the main execution."""
    mock_transport, _ = mock_datagram_endpoint

    with (
        patch(
            "asyncio.sleep", new=AsyncMock(side_effect=Exception("Unexpected error"))
        ),
        patch("airos.discovery._LOGGER.exception") as mock_log_exception,
        pytest.raises(AirOSListenerError) as excinfo,
    ):
        await airos_discover_devices(timeout=1)

    assert "cannot_connect" in str(excinfo.value)
    mock_log_exception.assert_called_once()
    close_mock = cast(MagicMock, mock_transport.close)
    close_mock.assert_called_once()
