"""Central logging setup: console + rotating file, no print() anywhere."""
from __future__ import annotations

import logging
import logging.handlers
from pathlib import Path

_FORMAT = "%(asctime)s %(levelname)-7s %(name)s: %(message)s"


def setup_logging(level: str = "INFO", data_dir: "Path | None" = None) -> None:
    root = logging.getLogger()
    if root.handlers:  # already configured (tests, reload)
        return
    root.setLevel(getattr(logging, level.upper(), logging.INFO))

    console = logging.StreamHandler()
    console.setFormatter(logging.Formatter(_FORMAT))
    root.addHandler(console)

    if data_dir is not None:
        log_dir = Path(data_dir) / "logs"
        log_dir.mkdir(parents=True, exist_ok=True)
        fileh = logging.handlers.RotatingFileHandler(
            log_dir / "behavision.log", maxBytes=5_000_000, backupCount=3,
            encoding="utf-8")
        fileh.setFormatter(logging.Formatter(_FORMAT))
        root.addHandler(fileh)