import asyncio
from types import SimpleNamespace
from typing import Any

import pytest
from bleak.exc import BleakDeviceNotFoundError

import k1link.device_plugins.xgrids_k1.ble.wifi_provisioning as wifi_module
from k1link.device_plugins.xgrids_k1.ble.wifi_provisioning import (
    FRAME_LENGTH,
    build_wifi_provisioning_frame,
    parse_wifi_status,
    provision_wifi_once,
    read_wifi_status_once,
)


def test_build_wifi_provisioning_frame_layout() -> None:
    credential = "x" * 13
    frame = build_wifi_provisioning_frame("LabNet", credential)

    assert len(frame) == FRAME_LENGTH
    assert frame[0] == 6
    assert frame[1:7] == b"LabNet"
    assert frame[7:33] == bytes(26)
    assert frame[33] == 13
    assert frame[34:47] == b"x" * 13
    assert frame[47:98] == bytes(51)
    assert frame[98] == 0


def test_build_wifi_provisioning_frame_uses_utf8_byte_lengths() -> None:
    ssid = "Ж" * 4
    credential = "я" * 6
    frame = build_wifi_provisioning_frame(ssid, credential)

    assert frame[0] == len(ssid.encode())
    assert frame[33] == len(credential.encode())


@pytest.mark.parametrize(
    ("ssid", "password", "message"),
    [
        ("", "x" * 8, "SSID must not be empty"),
        ("network", "", "password must not be empty"),
        ("x" * 33, "y" * 8, "at most 32 UTF-8 bytes"),
        ("network", "x" * 65, "at most 64 UTF-8 bytes"),
    ],
)
def test_build_wifi_provisioning_frame_rejects_invalid_lengths(
    ssid: str,
    password: str,
    message: str,
) -> None:
    with pytest.raises(ValueError, match=message):
        build_wifi_provisioning_frame(ssid, password)


def test_parse_wifi_status_ap_baseline() -> None:
    value = bytearray(54)
    value[0] = 7
    value[1:8] = b"WIFI_AP"
    value[33] = 4
    value[34:38] = bytes((192, 168, 56, 1))
    value[50] = 1
    value[52:54] = b"XX"

    assert parse_wifi_status(bytes(value)) == {
        "value_length": 54,
        "mode": "WIFI_AP",
        "ipv4": "192.168.56.1",
        "status_code": 1,
        "reserved": 0,
        "trailer_hex": "5858",
    }


def test_parse_wifi_status_rejects_short_frame() -> None:
    with pytest.raises(ValueError, match="at least 51 bytes"):
        parse_wifi_status(bytes(50))


def test_read_wifi_status_once_reads_only_and_returns_current_dhcp_address(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    value = bytearray(54)
    value[0] = 11
    value[1:12] = b"WIFI_CLIENT"
    value[33] = 4
    value[34:38] = bytes((10, 255, 254, 77))
    value[50] = 1
    characteristic = SimpleNamespace(
        uuid=wifi_module.STATUS_CHARACTERISTIC_UUID,
        service_uuid=wifi_module.SERVICE_UUID,
        properties=["read"],
    )
    service = SimpleNamespace(uuid=wifi_module.SERVICE_UUID)

    class FakeServices:
        def get_service(self, uuid: str) -> object | None:
            return service if uuid == wifi_module.SERVICE_UUID else None

        def get_characteristic(self, uuid: str) -> object | None:
            return characteristic if uuid == wifi_module.STATUS_CHARACTERISTIC_UUID else None

    class FakeClient:
        def __init__(self, _device: object, **_kwargs: object) -> None:
            self.services = FakeServices()
            self.name = "XGR-K1"
            self.write_calls = 0

        async def __aenter__(self) -> Any:
            return self

        async def __aexit__(self, *_args: object) -> None:
            return None

        async def read_gatt_char(self, _characteristic: object) -> bytes:
            return bytes(value)

        async def write_gatt_char(self, *_args: object, **_kwargs: object) -> None:
            self.write_calls += 1
            raise AssertionError("status refresh must not write a BLE characteristic")

    monkeypatch.setattr(wifi_module, "discovered_device", lambda _uuid: object())
    monkeypatch.setattr(wifi_module, "BleakClient", FakeClient)

    result = asyncio.run(read_wifi_status_once("synthetic-corebluetooth-uuid"))

    assert result["operation"] == "single_reviewed_wifi_status_read"
    assert result["write_performed"] is False
    assert result["status"]["ipv4"] == "10.255.254.77"


def test_read_wifi_status_recovery_rediscover_ignores_retained_handle(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    value = bytearray(54)
    value[0] = 11
    value[1:12] = b"WIFI_CLIENT"
    value[33] = 4
    value[34:38] = bytes((10, 255, 254, 77))
    value[50] = 1
    stale_handle = object()
    recovered_handle = object()
    characteristic = SimpleNamespace(
        uuid=wifi_module.STATUS_CHARACTERISTIC_UUID,
        service_uuid=wifi_module.SERVICE_UUID,
        properties=["read"],
    )
    service = SimpleNamespace(uuid=wifi_module.SERVICE_UUID)

    class FakeServices:
        def get_service(self, uuid: str) -> object | None:
            return service if uuid == wifi_module.SERVICE_UUID else None

        def get_characteristic(self, uuid: str) -> object | None:
            return characteristic if uuid == wifi_module.STATUS_CHARACTERISTIC_UUID else None

    class FakeClient:
        def __init__(self, device: object, **_kwargs: object) -> None:
            assert device is recovered_handle
            self.services = FakeServices()
            self.name = "XGR-K1"

        async def __aenter__(self) -> Any:
            return self

        async def __aexit__(self, *_args: object) -> None:
            return None

        async def read_gatt_char(self, _characteristic: object) -> bytes:
            return bytes(value)

    async def rediscover(*_args: object, **_kwargs: object) -> object:
        return recovered_handle

    monkeypatch.setattr(wifi_module, "discovered_device", lambda _uuid: stale_handle)
    monkeypatch.setattr(wifi_module.BleakScanner, "find_device_by_address", rediscover)
    monkeypatch.setattr(wifi_module, "BleakClient", FakeClient)

    result = asyncio.run(
        read_wifi_status_once(
            "synthetic-corebluetooth-uuid",
            rediscover=True,
        )
    )

    assert result["status"]["ipv4"] == "10.255.254.77"


def test_provisioning_write_requires_fresh_rediscovery_before_connecting(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    stale_handle = object()
    rediscovery_calls: list[tuple[str, float]] = []
    client_calls: list[object] = []

    async def missing_device(address: str, *, timeout: float) -> None:
        rediscovery_calls.append((address, timeout))
        return None

    class ForbiddenClient:
        def __init__(self, device: object, **_kwargs: object) -> None:
            client_calls.append(device)
            raise AssertionError("a failed fresh discovery must stop before the BLE write session")

    monkeypatch.setattr(wifi_module, "discovered_device", lambda _uuid: stale_handle)
    monkeypatch.setattr(
        wifi_module.BleakScanner,
        "find_device_by_address",
        missing_device,
    )
    monkeypatch.setattr(wifi_module, "BleakClient", ForbiddenClient)

    with pytest.raises(BleakDeviceNotFoundError):
        asyncio.run(
            provision_wifi_once(
                "synthetic-corebluetooth-uuid",
                "LabNet",
                "synthetic-password",
                timeout_seconds=1.0,
            )
        )

    assert rediscovery_calls == [("synthetic-corebluetooth-uuid", 1.0)]
    assert client_calls == []