#!/usr/bin/env python3
"""
Module: log_aggregator.py
Description: Centralizes all Genesis logs from various sources into a single,
             aggregated log file. This script is designed to be run as a
             system service and handles log rotation and configuration
             through environment variables.
"""

import os
import time
import logging
import logging.handlers
import sys
from typing import Optional, List

# Configuration constants - retrieve from environment or use defaults
LOG_LEVEL: str = os.getenv("LOG_AGGREGATOR_LOG_LEVEL", "INFO").upper()
LOG_FILE: str = os.getenv("LOG_AGGREGATOR_LOG_FILE", "/var/log/genesis/log_aggregator.log")
LOG_ROTATION_INTERVAL: str = os.getenv("LOG_AGGREGATOR_ROTATION_INTERVAL", "midnight")
LOG_RETENTION_COUNT: int = int(os.getenv("LOG_AGGREGATOR_RETENTION_COUNT", "7"))  # Number of days to keep logs


def setup_logging() -> logging.Logger:
    """
    Sets up the logging configuration for the log aggregator.  Includes
    setting the log level, format, handlers (file and stdout). Also handles
    log rotation.

    Returns:
        logging.Logger: The configured logger instance.
    """

    logger: logging.Logger = logging.getLogger(__name__)
    try:
        logger.setLevel(LOG_LEVEL)  # Set level from env var
    except ValueError:
        logger.setLevel("INFO")  # Default
        logger.warning(f"Invalid LOG_LEVEL '{LOG_LEVEL}'.  Using INFO.")

    formatter: logging.Formatter = logging.Formatter(
        "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
    )

    # File handler with rotation
    try:
        file_handler: logging.handlers.TimedRotatingFileHandler = logging.handlers.TimedRotatingFileHandler(
            LOG_FILE, when=LOG_ROTATION_INTERVAL, backupCount=LOG_RETENTION_COUNT, utc=True
        )
        file_handler.setFormatter(formatter)
        logger.addHandler(file_handler)
    except Exception as e:
        print(f"Error setting up file logging: {e}")
        sys.exit(1)

    # Console handler
    stream_handler: logging.StreamHandler = logging.StreamHandler(sys.stdout)
    stream_handler.setFormatter(formatter)
    logger.addHandler(stream_handler)

    logger.info("Log aggregator started.")
    return logger


def aggregate_logs(logger: logging.Logger) -> None:
    """
    Placeholder function for the actual log aggregation logic.
    In a real-world scenario, this function would:

    1.  Identify all log sources (e.g., files, databases, message queues)
    2.  Read logs from each source
    3.  Optionally, transform the logs into a common format
    4.  Write the aggregated logs to the central log file (handled by logging setup).

    For now, it simulates aggregation by logging a message periodically.

    Args:
        logger (logging.Logger): The logger instance.
    """

    logger.info("Starting log aggregation loop.")
    try:
        while True:
            # Simulate log aggregation activity
            logger.info("Aggregating logs... (simulated)")
            time.sleep(60)  # Check for new logs every 60 seconds
    except KeyboardInterrupt:
        logger.info("Log aggregator stopped by user.")
    except Exception as e:
        logger.exception(f"An error occurred during log aggregation: {e}")
        sys.exit(1)
    finally:
        logger.info("Log aggregator shutting down.")


def main() -> None:
    """
    Main function to initialize logging and start the log aggregation process.
    """
    logger: logging.Logger = setup_logging()
    aggregate_logs(logger)


if __name__ == "__main__":
    main()