"""pod_serial_test.py —— PodSerial 单元测试（注入 fake serial 模块，无硬件）。"""

import sys
import types

import pytest

from pod_bridge.pod_serial import PodLink, PodSerial
from pod_bridge.protocol import TargetGeo, encode_target


class _FakeSerialInstance:
    def __init__(self, **kwargs):
        self.kwargs = kwargs
        self._buf = b""
        self.written = []
        self.closed = False

    @property
    def in_waiting(self):
        return len(self._buf)

    def read(self, n):
        data, self._buf = self._buf[:n], self._buf[n:]
        return data

    def write(self, data):
        self.written.append(data)

    def close(self):
        self.closed = True


@pytest.fixture
def fake_serial(monkeypatch):
    mod = types.ModuleType("serial")
    mod.EIGHTBITS = 8
    mod.PARITY_NONE = "N"
    mod.STOPBITS_ONE = 1
    mod.Serial = _FakeSerialInstance
    monkeypatch.setitem(sys.modules, "serial", mod)
    return mod


def test_empty_port_raises():
    with pytest.raises(ValueError, match="port 为空"):
        PodSerial("")


def test_serial_opened_with_8n1(fake_serial):
    ps = PodSerial("COM3", baudrate=115200)
    kw = ps._ser.kwargs
    assert kw["port"] == "COM3"
    assert kw["baudrate"] == 115200
    assert kw["bytesize"] == 8
    assert kw["parity"] == "N"
    assert kw["stopbits"] == 1
    assert kw["timeout"] == 0  # 非阻塞轮询


def test_poll_parses_buffered_frames(fake_serial):
    ps = PodSerial("COM3")
    ps._ser._buf = encode_target(TargetGeo(latitude_deg=31.0, longitude_deg=121.0))
    frames = ps.poll()
    assert len(frames) == 1
    assert isinstance(frames[0], TargetGeo)
    assert frames[0].latitude_deg == pytest.approx(31.0, abs=1e-7)


def test_poll_empty_returns_empty_list(fake_serial):
    ps = PodSerial("COM3")
    assert ps.poll() == []


def test_send_writes_bytes(fake_serial):
    ps = PodSerial("COM3")
    ps.send(b"\xeb\x90\x01")
    assert ps._ser.written == [b"\xeb\x90\x01"]


def test_close_closes_serial(fake_serial):
    ps = PodSerial("COM3")
    ps.close()
    assert ps._ser.closed is True


def test_satisfies_podlink_protocol(fake_serial):
    ps = PodSerial("COM3")
    assert isinstance(ps, PodLink)