# logging_config.py - Production-ready logging configuration

import logging
import logging.handlers
import sys
import os
from typing import Optional

def setup_logging(log_level: str = "INFO", log_dir: str = "logs") -> None:
    """
    Configures structured logging for the AI Lab with rotation and proper encoding.
    
    Args:
        log_level: Logging level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
        log_dir: Directory for log files
    """
    try:
        os.makedirs(log_dir, exist_ok=True)
    except Exception as e:
        print(f"Error creating log directory: {e}")
        sys.exit(1)
        
    # Create formatters
    detailed_formatter = logging.Formatter(
        fmt="%(asctime)s [%(levelname)-8s] [%(name)-20s] %(funcName)-15s:%(lineno)-4d | %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S"
    )
    
    simple_formatter = logging.Formatter(
        fmt="%(asctime)s [%(levelname)s] %(message)s",
        datefmt="%H:%M:%S"
    )
    
    # Create handlers
    handlers = []
    
    # Rotating file handler with UTF-8 encoding
    try:
        file_handler = logging.handlers.RotatingFileHandler(
            filename=os.path.join(log_dir, "ai_lab.log"),
            maxBytes=10 * 1024 * 1024,  # 10MB per file
            backupCount=5,  # Keep 5 backup files
            encoding='utf-8',
            mode='a'
        )
        file_handler.setFormatter(detailed_formatter)
        file_handler.setLevel(getattr(logging, log_level))
        handlers.append(file_handler)
    except Exception as e:
        print(f"Warning: Could not create file handler: {e}")
    
    # Console handler with UTF-8 support
    console_handler = logging.StreamHandler(sys.stdout)
    console_handler.setFormatter(simple_formatter)
    console_handler.setLevel(logging.INFO)  # Console shows INFO and above
    
    # Ensure UTF-8 encoding on Windows
    if hasattr(console_handler.stream, 'reconfigure'):
        console_handler.stream.reconfigure(encoding='utf-8')
    
    handlers.append(console_handler)
    
    # Configure root logger
    root_logger = logging.getLogger()
    root_logger.setLevel(getattr(logging, log_level))
    
    # Remove any existing handlers
    for handler in root_logger.handlers[:]:
        root_logger.removeHandler(handler)
    
    # Add new handlers
    for handler in handlers:
        root_logger.addHandler(handler)
    
    # Configure third-party library logging levels
    noisy_libraries = [
        "httpx",
        "urllib3",
        "sentence_transformers",
        "transformers",
        "faiss",
        "openai",
        "httpcore",
        "langchain"
    ]
    
    for lib in noisy_libraries:
        logging.getLogger(lib).setLevel(logging.WARNING)
    
    # Log startup message
    logging.info("="*60)
    logging.info("AI Lab Logging System Initialized")
    logging.info(f"Log Level: {log_level}")
    logging.info(f"Log Directory: {os.path.abspath(log_dir)}")
    logging.info("="*60)

def get_logger(name: str) -> logging.Logger:
    """
    Get a logger instance for a specific module.
    
    Args:
        name: Name of the module/component
        
    Returns:
        Configured logger instance
    """
    return logging.getLogger(name)

def log_exception(logger: logging.Logger, e: Exception, context: str = "") -> None:
    """
    Helper function to log exceptions with full traceback.
    
    Args:
        logger: Logger instance to use
        e: Exception to log
        context: Additional context about where the exception occurred
    """
    import traceback
    
    error_msg = f"Exception in {context}: {str(e)}" if context else str(e)
    logger.error(error_msg)
    logger.debug(f"Traceback:\n{traceback.format_exc()}")

def setup_performance_logging() -> Optional[logging.Logger]:
    """
    Set up a separate performance logger for tracking execution times and metrics.
    
    Returns:
        Performance logger instance
    """
    perf_logger = logging.getLogger("performance")
    perf_logger.setLevel(logging.DEBUG)
    
    # Create performance log file
    try:
        perf_handler = logging.handlers.RotatingFileHandler(
            filename=os.path.join("logs", "performance.log"),
            maxBytes=5 * 1024 * 1024,  # 5MB
            backupCount=3,
            encoding='utf-8'
        )
        perf_formatter = logging.Formatter(
            fmt="%(asctime)s.%(msecs)03d | %(message)s",
            datefmt="%Y-%m-%d %H:%M:%S"
        )
        perf_handler.setFormatter(perf_formatter)
        perf_logger.addHandler(perf_handler)
        
        return perf_logger
    except Exception as e:
        print(f"Warning: Could not create performance logger: {e}")
        return None

# Context manager for timed operations
class LoggedTimer:
    """Context manager for logging operation execution time."""
    
    def __init__(self, logger: logging.Logger, operation_name: str):
        self.logger = logger
        self.operation_name = operation_name
        self.start_time = None
    
    def __enter__(self):
        import time
        self.start_time = time.time()
        self.logger.debug(f"Starting: {self.operation_name}")
        return self
    
    def __exit__(self, exc_type, exc_val, exc_tb):
        import time
        elapsed = time.time() - self.start_time
        if exc_type:
            self.logger.error(f"Failed: {self.operation_name} after {elapsed:.2f}s - {exc_val}")
        else:
            self.logger.debug(f"Completed: {self.operation_name} in {elapsed:.2f}s")

# Initialize logging when module is imported (can be overridden)
if __name__ != "__main__":
    # Auto-initialize with defaults when imported
    try:
        setup_logging()
    except Exception as e:
        print(f"Warning: Auto-initialization of logging failed: {e}")