"""Unit tests for `jetson.jtop_parser` (mocked — jetson-stats not installed in CI)."""

from __future__ import annotations

import csv
import json
import sys
from pathlib import Path
from types import SimpleNamespace

import pytest

JETSON_ROOT = Path(__file__).resolve().parents[2] / "jetson"
if str(JETSON_ROOT) not in sys.path:
    sys.path.insert(0, str(JETSON_ROOT))

import jtop_parser  # noqa: E402


def test_state_to_row_extracts_known_fields() -> None:
    # Arrange
    state = SimpleNamespace(
        ram=SimpleNamespace(used=2048, tot=8192),
        gpu=SimpleNamespace(load=72, freq=SimpleNamespace(cur=624)),
        cpu=SimpleNamespace(load_avg=42.0),
        temperature={"SOC": 51.0, "GPU": 49.0},
        power=SimpleNamespace(total=12000),
    )
    # Act
    row = jtop_parser.state_to_row(state)
    # Assert
    assert row["ram_used_mb"] == 2048
    assert row["ram_total_mb"] == 8192
    assert row["gpu_load_pct"] == 72
    assert row["gpu_freq_mhz"] == 624
    assert row["soc_temp_c"] == 51.0
    assert row["gpu_temp_c"] == 49.0
    assert row["power_mw"] == 12000


def test_run_emits_stub_row_when_jetson_stats_missing(tmp_path: Path) -> None:
    """On hosts without jetson-stats, run() must still produce a one-row CSV with stub metadata."""
    # Arrange
    out = tmp_path / "jtop.csv"
    # Force the ImportError path even if jetson-stats happens to be installed.
    sys.modules["jtop"] = None  # type: ignore[assignment]
    try:
        # Act
        n = jtop_parser.run(out, interval_s=0.01, samples_max=1)
        # Assert
        assert n == 1
        with out.open() as fh:
            rows = list(csv.DictReader(fh))
        assert len(rows) == 1
        extras = json.loads(rows[0]["extras_json"])
        assert extras["stub"] is True
        assert extras["missing_dep"] == "jetson-stats"
    finally:
        del sys.modules["jtop"]