from __future__ import annotations

import os
import shutil
import subprocess
import sys
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parents[1]
SOURCE_ROOT = PROJECT_ROOT / "src"


def _environment_with_source() -> dict[str, str]:
    environment = os.environ.copy()
    existing_pythonpath = environment.get("PYTHONPATH")
    paths = [str(SOURCE_ROOT)]
    if existing_pythonpath:
        paths.append(existing_pythonpath)
    environment["PYTHONPATH"] = os.pathsep.join(paths)
    return environment


def _assert_successful_help(result: subprocess.CompletedProcess[str]) -> None:
    assert result.returncode == 0, result.stderr
    assert "usage:" in result.stdout.lower()
    assert "GYXX Flow" in result.stdout


def test_python_module_help_has_no_filesystem_side_effects(tmp_path: Path) -> None:
    result = subprocess.run(
        [sys.executable, "-m", "gyxx_flow", "--help"],
        cwd=tmp_path,
        env=_environment_with_source(),
        capture_output=True,
        text=True,
        check=False,
    )

    _assert_successful_help(result)
    assert list(tmp_path.iterdir()) == []


def test_installed_console_script_help_has_no_filesystem_side_effects(
    tmp_path: Path,
) -> None:
    executable = shutil.which("gyxx", path=str(Path(sys.executable).parent))
    assert executable is not None, "The installed gyxx console script was not found"

    result = subprocess.run(
        [executable, "--help"],
        cwd=tmp_path,
        capture_output=True,
        text=True,
        check=False,
    )

    _assert_successful_help(result)
    assert list(tmp_path.iterdir()) == []