import os
import re
from pathlib import Path

_VERSION_PATTERN = re.compile(r"^\d+\.\d+\.\d+(?:[-+][0-9A-Za-z.-]+)?$")
_REVISION_PATTERN = re.compile(r"^[0-9a-f]{40}$")
_VERSION_FILE = Path(__file__).resolve().parents[2] / "VERSION"
LOCAL_REVISION = "local"


def read_version() -> str:
    value = _VERSION_FILE.read_text(encoding="utf-8").strip()
    if not _VERSION_PATTERN.fullmatch(value):
        raise RuntimeError("Invalid EventLens VERSION file")
    return value


def read_revision() -> str:
    value = os.environ.get("EVENTLENS_REVISION", "")
    if _REVISION_PATTERN.fullmatch(value):
        return value
    return LOCAL_REVISION


VERSION = read_version()