"""Public-boundary discipline check.

No file under `e2e/` may import `gps_denied_onboard.*` — the runner image
must NEVER reach into SUT source. This unit test grep-walks the tree and
fails fast if anyone smuggles an import in.
"""

from __future__ import annotations

import re
from pathlib import Path

E2E_ROOT = Path(__file__).resolve().parents[1]
_FORBIDDEN_IMPORT = re.compile(r"^\s*(?:from|import)\s+gps_denied_onboard\b")


def test_no_sut_imports_in_e2e_tree() -> None:
    """Walk every *.py under e2e/ and ensure none import gps_denied_onboard.*."""
    violations: list[tuple[Path, int, str]] = []
    for py in E2E_ROOT.rglob("*.py"):
        # Skip __pycache__ and this unit test file itself (it intentionally
        # mentions the SUT package name in the regex).
        if "__pycache__" in py.parts or py.name == "test_no_sut_imports.py":
            continue
        try:
            text = py.read_text(encoding="utf-8")
        except UnicodeDecodeError:
            continue
        for lineno, line in enumerate(text.splitlines(), start=1):
            if _FORBIDDEN_IMPORT.match(line):
                violations.append((py.relative_to(E2E_ROOT), lineno, line.strip()))
    assert not violations, (
        "Public-boundary discipline violated — e2e/ files import the SUT:\n  "
        + "\n  ".join(f"{p}:{ln}: {src}" for p, ln, src in violations)
    )