"""Phase Z family-template ↔ frame_contracts.yaml baseline invariant.

#52 F-2 option (c) lock (2026-05-19) — locks active contracted family count
at 11/11 with a WIP allowlist for the 2 untracked WIP family templates
documented in `templates/phase_z2/families/_WIP_FILES.md`. Any drift after
this point (new family file on disk without a contract entry, or a contract
entry pointing to a missing file) fails fast in CI.

References:
  - docs/architecture/INTEGRATION-AUDIT-01-REPORT.md §10.2 F-2
  - docs/architecture/IMP-18-SVG-GAP-REPORT.md L28/L30/L51
  - templates/phase_z2/families/_WIP_FILES.md (WIP allowlist source)
  - Gitea #52 (this reconciliation), #42 (promote/remove gate)

Pattern mirrors `tests/test_catalog_invariant.py` — fail fast with explicit
diff message if family ↔ contract surfaces drift.
"""
from __future__ import annotations

import re
from pathlib import Path

import yaml

PROJECT_ROOT = Path(__file__).parent.parent
FAMILIES_DIR = PROJECT_ROOT / "templates" / "phase_z2" / "families"
CATALOG_PATH = PROJECT_ROOT / "templates" / "phase_z2" / "catalog" / "frame_contracts.yaml"
WIP_DOC_PATH = FAMILIES_DIR / "_WIP_FILES.md"


def _load_contract_keys() -> set[str]:
    with CATALOG_PATH.open(encoding="utf-8") as f:
        catalog = yaml.safe_load(f)
    return {k for k, v in catalog.items() if isinstance(v, dict)}


def _load_disk_family_stems() -> set[str]:
    return {p.stem for p in FAMILIES_DIR.glob("*.html")}


def _load_wip_allowlist() -> set[str]:
    text = WIP_DOC_PATH.read_text(encoding="utf-8")
    return {m.group(1) for m in re.finditer(r"`([A-Za-z0-9_\-]+)\.html`", text)}


def test_contracts_set_equals_disk_families_minus_wip():
    """`frame_contracts.yaml` keys ↔ disk family stems minus WIP allowlist."""
    contracts = _load_contract_keys()
    disk = _load_disk_family_stems()
    wip = _load_wip_allowlist()
    expected = disk - wip
    missing = expected - contracts
    extra = contracts - expected
    assert not missing, (
        f"Family files on disk without frame_contracts.yaml entry "
        f"(and not in _WIP_FILES.md): {sorted(missing)}. "
        "Add a contract entry, or list the file in "
        "templates/phase_z2/families/_WIP_FILES.md as WIP."
    )
    assert not extra, (
        f"frame_contracts.yaml has entries with no matching family file: "
        f"{sorted(extra)}."
    )


def test_wip_allowlist_is_disk_only_and_uncontracted():
    """WIP allowlist names must exist on disk AND have no contract entry."""
    contracts = _load_contract_keys()
    disk = _load_disk_family_stems()
    wip = _load_wip_allowlist()
    missing_on_disk = wip - disk
    leaked_into_contracts = wip & contracts
    assert not missing_on_disk, (
        f"_WIP_FILES.md names files not on disk: {sorted(missing_on_disk)}."
    )
    assert not leaked_into_contracts, (
        f"_WIP_FILES.md names files that already have a contract entry: "
        f"{sorted(leaked_into_contracts)}. Promote via #42 instead — "
        "WIP allowlist must be disk-only / uncontracted."
    )