"""config_test.py —— 桥接配置加载与校验单元测试。"""

import json
from pathlib import Path

import pytest

from pod_bridge.config import (BridgeConfig, GuidanceConfig, PodSerialConfig,
                               load_from_json)

_DEFAULT_CONFIG = Path(__file__).resolve().parents[2] / "config" / "pod_bridge.json"


def _write(tmp_path, obj) -> str:
    p = tmp_path / "cfg.json"
    p.write_text(json.dumps(obj), encoding="utf-8")
    return str(p)


def test_shipped_default_config_loads():
    cfg = load_from_json(str(_DEFAULT_CONFIG))
    assert cfg.pod_serial.baudrate == 115200
    assert cfg.px4.connection_string == "udp://:14540"
    assert cfg.link.attitude_downlink_hz == pytest.approx(20.0)
    assert cfg.guidance.max_speed_mps == pytest.approx(5.0)
    assert cfg.guidance.stop_radius_m == pytest.approx(5.0)


def test_empty_json_uses_all_defaults(tmp_path):
    cfg = load_from_json(_write(tmp_path, {}))
    default = BridgeConfig()
    assert cfg.pod_serial == default.pod_serial
    assert cfg.px4 == default.px4
    assert cfg.link == default.link
    assert cfg.guidance == default.guidance


def test_partial_override_keeps_other_defaults(tmp_path):
    cfg = load_from_json(_write(tmp_path, {
        "pod_serial": {"port": "COM3"},
        "guidance": {"max_speed_mps": 8.0},
    }))
    assert cfg.pod_serial.port == "COM3"
    assert cfg.pod_serial.baudrate == 115200          # 默认回退
    assert cfg.guidance.max_speed_mps == 8.0
    assert cfg.guidance.stop_radius_m == GuidanceConfig().stop_radius_m  # 默认回退


def test_full_override_roundtrip(tmp_path):
    obj = {
        "pod_serial": {"port": "/dev/ttyUSB0", "baudrate": 115200},
        "px4": {"connection_string": "serial:///dev/ttyS1:57600"},
        "link": {"attitude_downlink_hz": 30.0, "telemetry_timeout_ms": 800},
        "guidance": {"frequency_hz": 20.0, "stop_radius_m": 3.0,
                     "max_speed_mps": 7.5, "speed_kp": 0.8, "yaw_kp": 1.5},
    }
    cfg = load_from_json(_write(tmp_path, obj))
    assert cfg.px4.connection_string == "serial:///dev/ttyS1:57600"
    assert cfg.link.attitude_downlink_hz == 30.0
    assert cfg.link.telemetry_timeout_ms == 800
    assert cfg.guidance.frequency_hz == 20.0
    assert cfg.guidance.yaw_kp == 1.5


# --- 校验错误 ---------------------------------------------------------------
def test_missing_file_raises():
    with pytest.raises(ValueError, match="打开失败"):
        load_from_json(str(_DEFAULT_CONFIG.parent / "no_such_file.json"))


def test_non_object_root_raises(tmp_path):
    p = tmp_path / "bad.json"
    p.write_text("[1, 2, 3]", encoding="utf-8")
    with pytest.raises(ValueError, match="根节点必须为对象"):
        load_from_json(str(p))


def test_malformed_json_raises(tmp_path):
    p = tmp_path / "bad.json"
    p.write_text("{not json", encoding="utf-8")
    with pytest.raises(ValueError, match="解析失败"):
        load_from_json(str(p))


def test_wrong_type_raises_with_field_name(tmp_path):
    with pytest.raises(ValueError, match="guidance.max_speed_mps"):
        load_from_json(_write(tmp_path, {"guidance": {"max_speed_mps": "fast"}}))


def test_unknown_key_rejected(tmp_path):
    with pytest.raises(ValueError, match="未知字段"):
        load_from_json(_write(tmp_path, {"guidance": {"max_speed": 5.0}}))


def test_empty_connection_string_raises(tmp_path):
    with pytest.raises(ValueError, match="px4.connection_string"):
        load_from_json(_write(tmp_path, {"px4": {"connection_string": ""}}))


@pytest.mark.parametrize("obj,field", [
    ({"link": {"attitude_downlink_hz": 100.0}}, "link.attitude_downlink_hz"),  # >60
    ({"link": {"attitude_downlink_hz": 0.5}}, "link.attitude_downlink_hz"),    # <1
    ({"guidance": {"max_speed_mps": -1.0}}, "guidance.max_speed_mps"),         # 非正
    ({"guidance": {"stop_radius_m": -2.0}}, "guidance.stop_radius_m"),         # 负
    ({"guidance": {"speed_derivative_filter_coef": 1.0}},                      # 上界开
     "guidance.speed_derivative_filter_coef"),
    ({"pod_serial": {"baudrate": 0}}, "pod_serial.baudrate"),                  # 非正
])
def test_out_of_range_raises(tmp_path, obj, field):
    with pytest.raises(ValueError, match=field.replace(".", r"\.")):
        load_from_json(_write(tmp_path, obj))


def test_pod_serial_default_port_is_placeholder():
    assert PodSerialConfig().port == ""