"""Unit tests for `jetson.tegrastats_parser`."""

from __future__ import annotations

import io
import json
from pathlib import Path

import pytest

# Add jetson/ to path so the module is importable as a flat script.
import sys
JETSON_ROOT = Path(__file__).resolve().parents[2] / "jetson"
if str(JETSON_ROOT) not in sys.path:
    sys.path.insert(0, str(JETSON_ROOT))

import tegrastats_parser  # noqa: E402


SAMPLE_LINE = (
    "11-21-2025 14:32:18 RAM 2345/7858MB (lfb 480x4MB) SWAP 0/0MB (cached 0MB) "
    "CPU [42%@1190,55%@1190,38%@1190,12%@729,off,off] EMC_FREQ 23%@665 "
    "GR3D_FREQ 67%@624 NVDEC off NVJPG off VIC_FREQ off APE 233 "
    "MTS fg 0% bg 1% AO@43.5C CPU@52.0C GPU@49.0C tj@52.0C VDD_IN 8200/8050 VDD_CPU 1500/1480 VDD_SOC 2300/2250 VDD_CV 1200/1180"
)


def test_parse_line_extracts_ram() -> None:
    row = tegrastats_parser.parse_line(SAMPLE_LINE)
    assert row is not None
    assert row["ram_used_mb"] == "2345"
    assert row["ram_total_mb"] == "7858"


def test_parse_line_extracts_gpu_load_and_freq() -> None:
    row = tegrastats_parser.parse_line(SAMPLE_LINE)
    assert row is not None
    assert row["gpu_load_pct"] == "67"
    assert row["gpu_freq_mhz"] == "624"


def test_parse_line_extracts_temperatures() -> None:
    row = tegrastats_parser.parse_line(SAMPLE_LINE)
    assert row is not None
    # SOC temp pattern matches "AO@43.5C" via the case-insensitive SoC fallback,
    # but more importantly GPU@49.0C is matched.
    assert row["gpu_temp_c"] == "49.0"


def test_parse_line_averages_cpu_loads() -> None:
    row = tegrastats_parser.parse_line(SAMPLE_LINE)
    assert row is not None
    # 42, 55, 38, 12 = avg 36.75 → "36.8"
    assert row["cpu_load_avg_pct"] == "36.8"


def test_parse_line_blank_returns_none() -> None:
    assert tegrastats_parser.parse_line("") is None
    assert tegrastats_parser.parse_line("   \n") is None


def test_parse_line_extras_json_round_trips() -> None:
    row = tegrastats_parser.parse_line(SAMPLE_LINE)
    assert row is not None
    extras = json.loads(str(row["extras_json"]))
    assert "raw" in extras


def test_stream_to_csv_writes_expected_columns(tmp_path: Path) -> None:
    # Arrange
    source = io.StringIO("\n".join([SAMPLE_LINE, SAMPLE_LINE]))
    out_path = tmp_path / "tegrastats.csv"
    # Act
    n = tegrastats_parser.stream_to_csv(source, out_path)
    # Assert
    assert n == 2
    text = out_path.read_text(encoding="utf-8")
    first_line = text.splitlines()[0]
    assert first_line == ",".join(tegrastats_parser.CSV_COLUMNS)