"""Published unreachable-engine stance, loaded from pep-stance.yaml.

The map MUST equal shipped behaviour. DefaultDenyWriteAuthorizer and
transport-failure deny both apply `fail_closed`. A published map that may
drift from this module is worse than none (§6.4 obligation 3).
"""

from __future__ import annotations

from pathlib import Path

STANCE_PATH = Path(__file__).resolve().parents[2] / "pep-stance.yaml"

# Shipped behaviour. pep-stance.yaml must equal this dict. Keep the two
# in lockstep — tests/test_layer_conformance.py compares them.
SHIPPED_STANCE: dict[str, str] = {
    "unset": "fail_closed",
    "unreachable": "fail_closed",
    "non_allow": "fail_closed",
    "unknown": "fail_closed",
}

FAIL_CLOSED = "fail_closed"


def shipped_stance() -> dict[str, str]:
    return dict(SHIPPED_STANCE)


def published_stance(text: str | None = None) -> dict[str, str]:
    """Parse the `stance:` map from pep-stance.yaml without a YAML runtime dep."""
    raw = text if text is not None else STANCE_PATH.read_text(encoding="utf-8")
    in_map = False
    parsed: dict[str, str] = {}
    for line in raw.splitlines():
        stripped = line.strip()
        if stripped.startswith("stance:"):
            in_map = True
            continue
        if in_map:
            if not stripped or stripped.startswith("#"):
                continue
            if not line.startswith(" ") and not line.startswith("\t"):
                break
            if ":" not in stripped:
                continue
            key, value = stripped.split(":", 1)
            parsed[key.strip()] = value.split("#", 1)[0].strip()
    return parsed