exceptions.py

"""
Custom exceptions and error handling for Silver Table Assistant.
Provides structured error handling and logging.
"""

import logging
from typing import Any, Dict, Optional
from fastapi import HTTPException, status
from sqlalchemy.exc import SQLAlchemyError, IntegrityError
try:
    from stripe import StripeError, CardError, AuthenticationError, InvalidRequestError
except ImportError:
    # Fallback for different stripe versions or if not installed
    class StripeError(Exception): pass
    class CardError(StripeError): pass
    class AuthenticationError(StripeError): pass
    class InvalidRequestError(StripeError): pass


# Configure logging
logger = logging.getLogger(__name__)


class SilverTableException(Exception):
    """Base exception for Silver Table Assistant."""
    
    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None):
        self.message = message
        self.details = details or {}
        super().__init__(self.message)
    
    def to_dict(self) -> Dict[str, Any]:
        """Convert exception to dictionary for logging/response."""
        return {
            "error": self.__class__.__name__,
            "message": self.message,
            "details": self.details
        }


class DatabaseException(SilverTableException):
    """Database-related errors."""
    pass


class PaymentException(SilverTableException):
    """Payment/Stripe-related errors."""
    pass


class AuthenticationException(SilverTableException):
    """Authentication-related errors."""
    pass


class ValidationException(SilverTableException):
    """Data validation errors."""
    pass


class ExternalServiceException(SilverTableException):
    """External service (OpenAI, etc.) errors."""
    pass


def handle_database_error(error: Exception, operation: str) -> DatabaseException:
    """Handle database errors with appropriate logging."""
    
    if isinstance(error, IntegrityError):
        message = f"Database integrity error during {operation}"
        logger.error(f"{message}: {str(error)}", extra={"error_type": "integrity_error"})
    elif isinstance(error, SQLAlchemyError):
        message = f"Database operation failed during {operation}"
        logger.error(f"{message}: {str(error)}", extra={"error_type": "sqlalchemy_error"})
    else:
        message = f"Unexpected database error during {operation}"
        logger.error(f"{message}: {str(error)}", extra={"error_type": "unknown_db_error"})
    
    return DatabaseException(message, {"operation": operation, "original_error": str(error)})


def handle_payment_error(error: Exception, operation: str) -> PaymentException:
    """Handle Stripe payment errors with appropriate logging."""
    
    if isinstance(error, CardError):
        message = f"Payment card error during {operation}: {error.user_message}"
        logger.warning(f"{message}: {str(error)}", extra={"error_type": "card_error"})
    elif isinstance(error, AuthenticationError):
        message = f"Payment authentication error during {operation}"
        logger.error(f"{message}: {str(error)}", extra={"error_type": "auth_error"})
    elif isinstance(error, InvalidRequestError):
        message = f"Invalid payment request during {operation}: {str(error)}"
        logger.warning(f"{message}: {str(error)}", extra={"error_type": "invalid_request"})
    elif isinstance(error, StripeError):
        message = f"Stripe error during {operation}: {str(error)}"
        logger.error(f"{message}: {str(error)}", extra={"error_type": "stripe_error"})
    else:
        message = f"Unexpected payment error during {operation}"
        logger.error(f"{message}: {str(error)}", extra={"error_type": "unknown_payment_error"})
    
    return PaymentException(message, {"operation": operation, "original_error": str(error)})


def handle_external_service_error(error: Exception, service: str, operation: str) -> ExternalServiceException:
    """Handle external service errors (OpenAI, etc.)."""
    
    message = f"{service} service error during {operation}: {str(error)}"
    logger.error(message, extra={"error_type": "external_service_error", "service": service})
    
    return ExternalServiceException(
        message, 
        {"service": service, "operation": operation, "original_error": str(error)}
    )


def handle_authentication_error(error: Exception, operation: str) -> AuthenticationException:
    """Handle authentication errors."""
    
    message = f"Authentication error during {operation}: {str(error)}"
    logger.warning(message, extra={"error_type": "auth_error"})
    
    return AuthenticationException(message, {"operation": operation, "original_error": str(error)})


def handle_validation_error(error: Exception, field: str, operation: str) -> ValidationException:
    """Handle validation errors."""
    
    message = f"Validation error in {field} during {operation}: {str(error)}"
    logger.warning(message, extra={"error_type": "validation_error", "field": field})
    
    return ValidationException(
        message, 
        {"field": field, "operation": operation, "original_error": str(error)}
    )


def http_exception_from_custom(exception: SilverTableException, status_code: int = status.HTTP_500_INTERNAL_SERVER_ERROR) -> HTTPException:
    """Convert custom exception to FastAPI HTTPException."""
    
    return HTTPException(
        status_code=status_code,
        detail={
            "error": exception.__class__.__name__,
            "message": exception.message,
            "details": exception.details
        }
    )


def log_and_handle_error(
    error: Exception, 
    context: str, 
    operation: str,
    reraise: bool = True
) -> Optional[SilverTableException]:
    """
    Centralized error handling with logging.
    
    Args:
        error: The exception that occurred
        context: Context where the error occurred
        operation: Operation being performed
        reraise: Whether to reraise as custom exception
        
    Returns:
        Custom exception if not reraising, None otherwise
    """
    
    try:
        if isinstance(error, (SQLAlchemyError, IntegrityError)):
            custom_exception = handle_database_error(error, operation)
        elif isinstance(error, StripeError):
            custom_exception = handle_payment_error(error, operation)
        elif isinstance(error, (AuthenticationError,)):
            custom_exception = handle_authentication_error(error, operation)
        else:
            # Generic error handling
            message = f"Unexpected error during {operation} in {context}: {str(error)}"
            logger.error(message, extra={"error_type": "unexpected_error", "context": context})
            custom_exception = SilverTableException(
                message, 
                {"context": context, "operation": operation, "original_error": str(error)}
            )
        
        if reraise:
            raise custom_exception
        else:
            return custom_exception
            
    except Exception as handling_error:
        logger.error(f"Error in error handler: {str(handling_error)}")
        if reraise:
            raise SilverTableException(f"Error handling failed: {str(handling_error)}")
        else:
            return SilverTableException(f"Error handling failed: {str(handling_error)}")


# Context manager for database operations
class DatabaseTransaction:
    """Context manager for database transactions with proper error handling."""
    
    def __init__(self, session):
        self.session = session
    
    async def __aenter__(self):
        return self.session
    
    async def __aexit__(self, exc_type, exc_val, exc_tb):
        if exc_type is not None:
            # Rollback on error
            await self.session.rollback()
            logger.error(f"Database transaction rolled back due to: {exc_val}")
        else:
            # Commit on success
            try:
                await self.session.commit()
            except Exception as e:
                await self.session.rollback()
                raise handle_database_error(e, "transaction_commit")
        
        await self.session.close()


# Decorator for automatic error handling
def handle_errors(operation: str, reraise: bool = True):
    """Decorator for automatic error handling in functions."""
    
    def decorator(func):
        async def wrapper(*args, **kwargs):
            try:
                return await func(*args, **kwargs)
            except Exception as e:
                return log_and_handle_error(e, func.__name__, operation, reraise)
        
        return wrapper
    
    return decorator