import logging
from pathlib import Path

def setup_logging(app_env: str):
    logger = logging.getLogger()
    logger.setLevel(logging.INFO)

    fmt = logging.Formatter("%(asctime)s [%(levelname)s] %(message)s")

    # Always log to console (terminal / systemd)
    sh = logging.StreamHandler()
    sh.setFormatter(fmt)
    logger.addHandler(sh)

    # Dev → additional file logging
    if app_env == "dev":
        log_dir = Path("logs")
        log_dir.mkdir(exist_ok=True)
        fh = logging.FileHandler(log_dir / "app.log", encoding="utf-8")
        fh.setFormatter(fmt)
        logger.addHandler(fh)

    return logger