"""
Unified logging module.
Provides a pre-configured logger with console + rotating file handlers.
"""

import logging
import os
from logging.handlers import TimedRotatingFileHandler


def setup_logger(name='app', log_dir=None, level='INFO', max_keep_days=30):
    """Create and configure a logger.

    Args:
        name: Logger name (used as basename for log file).
        log_dir: Directory for log files. Defaults to <project_root>/logs.
        level: Logging level string (DEBUG, INFO, WARNING, ERROR).
        max_keep_days: Number of days to retain rotated log files.

    Returns:
        Configured logging.Logger instance.
    """
    if log_dir is None:
        log_dir = 'logs'
    # Resolve relative paths against project root
    project_root = os.path.dirname(os.path.abspath(__file__))
    if not os.path.isabs(log_dir):
        log_dir = os.path.join(project_root, log_dir)
    os.makedirs(log_dir, exist_ok=True)

    logger = logging.getLogger(name)
    logger.setLevel(getattr(logging, level.upper(), logging.INFO))

    # Avoid adding duplicate handlers on repeated calls
    if logger.handlers:
        return logger

    fmt = logging.Formatter(
        '%(asctime)s [%(levelname)s] %(message)s',
        datefmt='%Y-%m-%d %H:%M:%S'
    )

    # Console handler
    ch = logging.StreamHandler()
    ch.setLevel(getattr(logging, level.upper(), logging.INFO))
    ch.setFormatter(fmt)
    logger.addHandler(ch)

    # File handler — rotate daily, keep max_keep_days backups
    log_file = os.path.join(log_dir, f'{name}.log')
    fh = TimedRotatingFileHandler(
        log_file, when='midnight', interval=1,
        backupCount=max_keep_days, encoding='utf-8'
    )
    fh.setLevel(getattr(logging, level.upper(), logging.INFO))
    fh.setFormatter(fmt)
    fh.suffix = '%Y-%m-%d'
    logger.addHandler(fh)

    return logger


def get_logger(name='app'):
    """Get an existing logger by name (does not reconfigure)."""
    return logging.getLogger(name)