import os
import logging
from logging.handlers import RotatingFileHandler

# Ensure logs directory exists at the project root
PROJECT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), '..', '..'))
LOGS_DIR = os.path.join(PROJECT_ROOT, "logs")
os.makedirs(LOGS_DIR, exist_ok=True)

LOG_FILE = os.path.join(LOGS_DIR, "model_io.log")

def get_logger(name: str) -> logging.Logger:
    """
    Returns a configured logger with a RotatingFileHandler.
    Logs are written to logs/model_io.log with a max size of 5MB and 3 backups.
    """
    logger = logging.getLogger(name)
    
    # Only configure if no handlers are present to avoid duplicate logs
    if not logger.handlers:
        logger.setLevel(logging.INFO)
        
        # 5 MB max per file, keep 3 old copies
        file_handler = RotatingFileHandler(
            LOG_FILE, maxBytes=5 * 1024 * 1024, backupCount=3, encoding='utf-8'
        )
        file_handler.setLevel(logging.INFO)
        
        # Optional: Console handler for real-time visibility
        console_handler = logging.StreamHandler()
        console_handler.setLevel(logging.INFO)
        
        formatter = logging.Formatter(
            '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
        )
        file_handler.setFormatter(formatter)
        console_handler.setFormatter(formatter)
        
        logger.addHandler(file_handler)
        logger.addHandler(console_handler)
        
    return logger