"""Logging setup for the backend.

Follows the project's output contract: all log output goes to stderr,
level controlled via the LOG_LEVEL env var (default INFO). This is server
logging, not the request/response payload — that stays in FastAPI's
responses.
"""

from __future__ import annotations

import logging
import os
import sys


def configure_logging() -> None:
    level_name = os.environ.get("LOG_LEVEL", "INFO").upper()
    level = getattr(logging, level_name, logging.INFO)

    handler = logging.StreamHandler(sys.stderr)
    handler.setFormatter(logging.Formatter("%(asctime)s %(levelname)-5s %(name)s: %(message)s"))

    root = logging.getLogger()
    root.setLevel(level)
    root.handlers = [handler]