import logging
import os
import sys


from src.utils import run_manager


def _debug_enabled():
    """Return whether verbose logging was requested for this process."""
    env_value = os.getenv("DEBUG_LOGGING", "").strip().lower()
    return "--debug" in sys.argv or env_value in {"1", "true", "yes", "on"}


def setup_logger(name, debug=None):
    """
    Sets up a logger with a standard configuration that logs to the console,
    the active run log file ('logs/run_<N>.log'), and mirrors to 'logs/app.log'.

    Pass ``--debug`` to the application command, or set ``DEBUG_LOGGING=true``,
    to enable DEBUG-level output.
    """
    logger = logging.getLogger(name)
    level = logging.DEBUG if (_debug_enabled() if debug is None else debug) else logging.INFO
    logger.setLevel(level)
    
    # If logger already has handlers, don't add more (to avoid duplicate logs).
    if not logger.handlers:
        run_number = run_manager.get_current_run_number()
        run_log_path = run_manager.get_current_run_log_file()
        logs_dir = os.path.dirname(run_log_path)
        os.makedirs(logs_dir, exist_ok=True)

        # Create formatters with run number
        formatter = logging.Formatter(
            f'%(asctime)s - [Run #{run_number}] - %(name)s - %(levelname)s - %(message)s'
        )
        
        # Console Handler
        console_handler = logging.StreamHandler()
        console_handler.setLevel(level)
        console_handler.setFormatter(formatter)
        logger.addHandler(console_handler)
        
        # Run-specific File Handler
        run_file_handler = logging.FileHandler(run_log_path, encoding='utf-8')
        run_file_handler.setLevel(level)
        run_file_handler.setFormatter(formatter)
        logger.addHandler(run_file_handler)

        # Legacy / general app.log File Handler in the same logs directory
        app_log_path = os.path.join(logs_dir, "app.log")
        app_file_handler = logging.FileHandler(app_log_path, encoding='utf-8')
        app_file_handler.setLevel(level)
        app_file_handler.setFormatter(formatter)
        logger.addHandler(app_file_handler)
    else:
        # A module may have configured this logger before the debug flag was
        # evaluated. Keep its existing handlers in sync with the logger level.
        for handler in logger.handlers:
            handler.setLevel(level)
        
    return logger