import logging
import os
from logging.handlers import RotatingFileHandler

# Define paths
BASE_DIR = os.path.dirname(os.path.abspath(__file__))
# Fallback to local 'logs' dir if not overridden in Docker
LOGS_DIR = os.environ.get("LOGS_DIR", os.path.join(BASE_DIR, "logs"))

# Ensure directory exists
os.makedirs(LOGS_DIR, exist_ok=True)

LOG_FILE_PATH = os.path.join(LOGS_DIR, "backend.log")

def setup_logger():
    logger = logging.getLogger("ainventory")
    # Set to DEBUG for development; change to INFO for production
    log_level = os.environ.get("LOG_LEVEL", "DEBUG")
    logger.setLevel(getattr(logging, log_level.upper(), logging.INFO))
    
    # Avoid duplicate handlers if setup multiple times
    if logger.handlers:
        return logger

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

    # File Handler (10MB max, keep 5 backups)
    try:
        file_handler = RotatingFileHandler(
            LOG_FILE_PATH, maxBytes=10*1024*1024, backupCount=5
        )
        file_handler.setFormatter(formatter)
        logger.addHandler(file_handler)
        
        # Special redirect for uvicorn logs to also go to file
        logging.getLogger("uvicorn").addHandler(file_handler)
        logging.getLogger("uvicorn.access").addHandler(file_handler)
    except (PermissionError, IOError) as e:
        logger.warning(f"⚠️ [LOGGING] Cannot write to log file at {LOG_FILE_PATH}: {e}")
        logger.warning("⚠️ [LOGGING] Continuing with console-only output.")

    # Console Handler (always registered)
    console_handler = logging.StreamHandler()
    console_handler.setFormatter(formatter)
    logger.addHandler(console_handler)

    return logger

log = setup_logger()