"""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.

IMP-04b (#42) extends the rule with a second exemption axis: catalog entries
flagged `visual_pending: true` are contracted but have no family partial on
disk yet (Track A/B VP frames). The invariant becomes:

  contracts == (disk - wip) ∪ vp

where `vp ∩ disk == ∅` (VP entry with disk file = promotion overdue).

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 + VP axis)

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"
V4_EVIDENCE_PATH = PROJECT_ROOT / "tests" / "matching" / "v4_full32_result.yaml"


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 _load_v4_evidence_template_ids() -> set[str]:
    """Unique `template_id` values across all V4 full32 judgments.

    IMP-04b (#42) closure gate derives its 32-frame target from V4 evidence
    rather than a hardcoded count, so future Track C additions extend both
    surfaces in lockstep.
    """
    with V4_EVIDENCE_PATH.open(encoding="utf-8") as f:
        v4 = yaml.safe_load(f)
    return {
        j["template_id"]
        for sec in v4["mdx_sections"].values()
        for j in sec.get("judgments_full32", [])
        if "template_id" in j
    }


def _load_vp_exempt_keys() -> set[str]:
    """Catalog entries flagged `visual_pending: true` (IMP-04b / #42).

    VP = contracted but no family partial on disk yet (Track A/B VP frames).
    Exempt from the disk-family existence check until the partial is authored.
    """
    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) and v.get("visual_pending") is True
    }


def test_contracts_set_equals_disk_families_minus_wip():
    """`frame_contracts.yaml` keys ↔ (disk family stems − WIP) ∪ VP-exempt."""
    contracts = _load_contract_keys()
    disk = _load_disk_family_stems()
    wip = _load_wip_allowlist()
    vp = _load_vp_exempt_keys()
    expected = disk - wip
    missing = expected - contracts
    extra = (contracts - vp) - 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"(and not flagged `visual_pending: true`): {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."
    )


def test_vp_exempt_keys_are_contracted_and_disk_absent():
    """VP-exempt keys: must be in catalog (by construction) AND must not have
    a family partial on disk (VP = pending partial authoring per #42)."""
    contracts = _load_contract_keys()
    disk = _load_disk_family_stems()
    vp = _load_vp_exempt_keys()
    leaked_outside_contracts = vp - contracts
    has_disk_partial = vp & disk
    assert not leaked_outside_contracts, (
        f"VP-exempt keys not in catalog: {sorted(leaked_outside_contracts)}."
    )
    assert not has_disk_partial, (
        f"VP-exempt entries have a family partial on disk: "
        f"{sorted(has_disk_partial)}. Drop `visual_pending: true` from the "
        "catalog entry (authoring complete) instead of carrying the flag."
    )


def test_imp04b_closure_gate_v4_coverage_and_wip_empty():
    """IMP-04b (#42) u24 closure gate: catalog set-equals V4 evidence + WIP==0.

    Locks the 32/32 frame coverage by comparing catalog top-level keys to
    `tests/matching/v4_full32_result.yaml` unique `template_id` values, and
    asserts the WIP allowlist is empty (both partials absorbed in u3/u4).
    """
    contracts = _load_contract_keys()
    wip = _load_wip_allowlist()
    v4_template_ids = _load_v4_evidence_template_ids()
    missing = v4_template_ids - contracts
    extra = contracts - v4_template_ids
    assert not missing, (
        f"IMP-04b closure gate: V4 template_ids not in frame_contracts.yaml: "
        f"{sorted(missing)}."
    )
    assert not extra, (
        f"IMP-04b closure gate: frame_contracts.yaml has entries outside "
        f"V4 evidence: {sorted(extra)}. Extend V4 evidence first or scope "
        "the addition under a follow-up IMP."
    )
    assert not wip, (
        f"IMP-04b closure gate: WIP allowlist must be empty: {sorted(wip)}."
    )