"""Single source of truth for the app version (charter §4: client and API share
one version). Reads the repo-root /VERSION file — the ONLY place a human edits the
version. Mirrors canon_log._schema_dir's env-override + walk-up so it resolves in
a local checkout and (once /VERSION is bundled) an image alike.
"""
import os
from functools import lru_cache
from pathlib import Path

LAST_RESORT = "0.0.0-dev"


def _version_file() -> Path | None:
    env = os.environ.get("COC_VERSION_FILE")
    if env:
        return Path(env)
    here = Path(__file__).resolve()
    for parent in here.parents:
        candidate = parent / "VERSION"
        if candidate.is_file():
            return candidate
    return None


@lru_cache(maxsize=1)
def get_version() -> str:
    path = _version_file()
    if path is None or not path.is_file():
        return LAST_RESORT
    return path.read_text(encoding="utf-8").strip() or LAST_RESORT


VERSION = get_version()