"""Contract tests for scripts/ci/classify_changes.py.

Each case asserts the *relationship* between a changed-file set and the lanes
that must run — the safety contract of the gating, not a snapshot. Governing
invariant: fail open. We may run a lane we didn't need, never skip one a
change could have broken.
"""

from __future__ import annotations

import importlib.util
from pathlib import Path

import pytest

_PATH = Path(__file__).resolve().parents[2] / "scripts" / "ci" / "classify_changes.py"
_spec = importlib.util.spec_from_file_location("classify_changes", _PATH)
_mod = importlib.util.module_from_spec(_spec)
_spec.loader.exec_module(_mod)
classify = _mod.classify

ALL = {"python": True, "frontend": True, "site": True}


def _lanes(python=False, frontend=False, site=False) -> dict[str, bool]:
    return {"python": python, "frontend": frontend, "site": site}


CASES = {
    "docs-only → nothing heavy": (["README.md", "docs/guide.md"], _lanes()),
    "python source → python": (["run_agent.py"], _lanes(python=True)),
    "dep manifest → python": (["pyproject.toml"], _lanes(python=True)),
    "uv.lock → python": (["uv.lock"], _lanes(python=True)),
    "ts package → frontend": (["apps/desktop/src/app.tsx"], _lanes(frontend=True)),
    "ui-tui → frontend": (["ui-tui/src/entry.ts"], _lanes(frontend=True)),
    # Lockfile bump shifts every TS package's tree, but not the Python suite.
    "root lockfile → frontend, not python": (["package-lock.json"], _lanes(frontend=True)),
    "website → site": (["website/docs/intro.md"], _lanes(site=True)),
    # SKILL.md reads like docs, but the skill-doc tests read skills/, so a
    # skill edit must still run Python.
    "skill md → python + site": (["skills/github/SKILL.md"], _lanes(python=True, site=True)),
    # Unknown top-level file keeps Python on rather than risk a silent skip.
    "unknown toplevel → python": (["Makefile"], _lanes(python=True)),
    "mixed docs+python → python": (["README.md", "agent/x.py"], _lanes(python=True)),
    "mixed docs+frontend → frontend": (["README.md", "apps/x.tsx"], _lanes(frontend=True)),
    # Fail open: CI-config / empty / blank diffs run everything.
    ".github change → all": ([".github/workflows/tests.yml"], ALL),
    "action change → all": ([".github/actions/detect-changes/action.yml"], ALL),
    "empty diff → all": ([], ALL),
    "blank lines → all": (["", "  "], ALL),
}


@pytest.mark.parametrize("files,expected", CASES.values(), ids=CASES.keys())
def test_classify(files, expected):
    assert classify(files) == expected