"""Logging helpers for the reactor simulation package."""

from __future__ import annotations

import logging
from typing import Optional


def configure_logging(level: int | str = "INFO", logfile: Optional[str] = None) -> logging.Logger:
    """Configure a package-scoped logger emitting to stdout and optional file."""
    resolved_level = logging.getLevelName(level) if isinstance(level, str) else level
    logger = logging.getLogger("reactor_sim")
    logger.setLevel(resolved_level)
    if not logger.handlers:
        stream_handler = logging.StreamHandler()
        formatter = logging.Formatter(
            fmt="%(asctime)s | %(levelname)s | %(name)s | %(message)s", datefmt="%H:%M:%S"
        )
        stream_handler.setFormatter(formatter)
        logger.addHandler(stream_handler)
        if logfile:
            file_handler = logging.FileHandler(logfile)
            file_handler.setFormatter(formatter)
            logger.addHandler(file_handler)
    else:
        for handler in logger.handlers:
            handler.setLevel(resolved_level)
        if logfile and not any(isinstance(handler, logging.FileHandler) for handler in logger.handlers):
            file_handler = logging.FileHandler(logfile)
            formatter = logging.Formatter(
                fmt="%(asctime)s | %(levelname)s | %(name)s | %(message)s", datefmt="%H:%M:%S"
            )
            file_handler.setFormatter(formatter)
            logger.addHandler(file_handler)
    # Keep package loggers self-contained so host apps can opt-in to propagation.
    logger.propagate = False
    logging.getLogger().setLevel(resolved_level)
    return logger