"""协议层单元测试（无第三方依赖，直接运行）。

用法：python3 tests/test_protocol.py
"""

import os
import sys

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from app import protocol  # noqa: E402
from app.protocol import (MsgDisHighVolBusFb, MsgDisHighAVolBusFb,  # noqa: E402
                          MsgDisLowMainBusFb, MsgDisLowBusFb,
                          MsgDisHVBCmd, MsgDisHVBACmd, MsgDisLVMBCmd,
                          MsgDisLVBCmd)


def test_expected_sizes():
    # 与 C++ pmSysvariable.h 结构体大小对齐
    expected = {
        MsgDisHighVolBusFb: 53,
        MsgDisHighAVolBusFb: 25,
        MsgDisLowMainBusFb: 34,
        MsgDisLowBusFb: 29,
        MsgDisHVBCmd: 14,
        MsgDisHVBACmd: 6,
        MsgDisLVMBCmd: 7,
        MsgDisLVBCmd: 8,
    }
    for cls, size in expected.items():
        assert cls.body_size() == size, f"{cls.__name__} 应为 {size}，实际 {cls.body_size()}"


def test_roundtrip():
    for cls in (MsgDisHighVolBusFb, MsgDisHighAVolBusFb, MsgDisLowMainBusFb,
                MsgDisLowBusFb, MsgDisHVBCmd, MsgDisHVBACmd, MsgDisLVMBCmd,
                MsgDisLVBCmd):
        m = cls()
        for i, name in enumerate(m.field_names()):
            setattr(m, name, (i + 1) % 256)
        data = m.pack()
        assert len(data) == 6 + cls.body_size() + 1
        assert protocol.msg_id_of(data) == cls.MSG_ID
        m2 = cls()
        assert m2.unpack(data)
        for name in m.field_names():
            assert getattr(m2, name) == getattr(m, name), f"{cls.__name__}.{name}"


def test_checksum_reject():
    for cls in (MsgDisHighVolBusFb, MsgDisHVBACmd):
        data = bytearray(cls().pack())
        data[6] ^= 0xFF
        assert not cls().unpack(bytes(data))


def test_bad_start_byte_reject():
    data = bytearray(MsgDisHVBCmd().pack())
    data[0] = 0x00
    assert protocol.msg_id_of(bytes(data)) is None
    assert not MsgDisHVBCmd().unpack(bytes(data))


def test_unknown_id():
    data = protocol.MsgDisHVBCmd().pack()
    data = data[0:2] + b'\x00\x00' + data[4:]  # 把 id 改为 0x0000
    assert protocol.msg_id_of(data) == 0x0000
    assert protocol.make_message(0x0000) is None
    assert protocol.make_message(MsgDisHVBCmd.MSG_ID).MSG_ID == MsgDisHVBCmd.MSG_ID


def test_short_frame_reject():
    data = MsgDisHVBCmd().pack()[:10]
    assert not MsgDisHVBCmd().unpack(data)


def run_all():
    tests = [v for k, v in sorted(globals().items()) if k.startswith("test_")]
    failed = 0
    for t in tests:
        try:
            t()
            print(f"  [OK] {t.__name__}")
        except Exception as e:
            failed += 1
            print(f"  [FAIL] {t.__name__}: {e}")
    print("TEST:", "PASS" if failed == 0 else f"FAIL ({failed})")
    return 1 if failed else 0


if __name__ == "__main__":
    sys.exit(run_all())