import logging
import sys

# Initialize logger
logger = logging.getLogger("proxy_debug")
logger.setLevel(logging.DEBUG)
logger.propagate = False

formatter = logging.Formatter(
    "[{asctime}] PROXY DEBUG: {message}", datefmt="%Y-%m-%d %H:%M:%S", style="{"
)

try:
    file_handler = logging.FileHandler("/var/log/proxy_debug.log")
    file_handler.setFormatter(formatter)
    logger.addHandler(file_handler)
except OSError as e:
    stream_handler = logging.StreamHandler(sys.stderr)
    stream_handler.setFormatter(formatter)
    logger.addHandler(stream_handler)
    logger.error(f"Failed to configure file logger: {e}")


def debug_log(message: str) -> None:
    """
    Appends a timestamped debug message.
    Utilizes the standard logging module for thread safety.
    """
    logger.debug(message)