utils/error_handling.py

"""
Error handling utilities for the MONA application
Fixed version with proper exception handling and logging
"""

import functools
import traceback
from typing import Any, Callable, Dict, Optional, Union

from utils.logging import get_logger, log_error, log_warning


class DataError(Exception):
    """Custom exception for data-related errors"""
    def __init__(self, message: str, error_code: str = None, details: Dict = None):
        self.message = message
        self.error_code = error_code or "DATA_ERROR"
        self.details = details or {}
        super().__init__(self.message)


class ValidationError(Exception):
    """Custom exception for validation errors"""
    def __init__(self, message: str, field: str = None, value: Any = None):
        self.message = message
        self.field = field
        self.value = value
        super().__init__(self.message)


class ProcessingError(Exception):
    """Custom exception for processing errors"""
    def __init__(self, message: str, step: str = None, context: Dict = None):
        self.message = message
        self.step = step
        self.context = context or {}
        super().__init__(self.message)


def handle_data_exceptions(func: Callable) -> Callable:
    """
    Decorator to handle data-related exceptions
    
    Args:
        func: Function to wrap with exception handling
        
    Returns:
        Wrapped function with exception handling
    """
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        try:
            return func(*args, **kwargs)
        except DataError as e:
            log_error(f"Data error in {func.__name__}: {e.message}", 
                     error=e, 
                     extra_data={"error_code": e.error_code, "details": e.details})
            raise
        except ValidationError as e:
            log_error(f"Validation error in {func.__name__}: {e.message}",
                     error=e,
                     extra_data={"field": e.field, "value": e.value})
            raise
        except ProcessingError as e:
            log_error(f"Processing error in {func.__name__}: {e.message}",
                     error=e,
                     extra_data={"step": e.step, "context": e.context})
            raise
        except Exception as e:
            log_error(f"Unexpected error in {func.__name__}: {str(e)}", 
                     error=e)
            raise ProcessingError(f"Unexpected error in {func.__name__}", 
                                context={"original_error": str(e)})
    
    return wrapper


def safe_execute(func: Callable, *args, default_return=None, **kwargs) -> tuple:
    """
    Safely execute a function and return success status with result
    
    Args:
        func: Function to execute
        *args: Positional arguments for the function
        default_return: Default value to return on error
        **kwargs: Keyword arguments for the function
        
    Returns:
        tuple: (success: bool, result: Any, error: Optional[Exception])
    """
    try:
        result = func(*args, **kwargs)
        return True, result, None
    except Exception as e:
        log_error(f"Error executing {func.__name__}: {str(e)}", error=e)
        return False, default_return, e


def validate_data(data: Any, validation_rules: Dict) -> bool:
    """
    Validate data against a set of rules
    
    Args:
        data: Data to validate
        validation_rules: Dictionary of validation rules
        
    Returns:
        bool: True if validation passes
        
    Raises:
        ValidationError: If validation fails
    """
    if not isinstance(validation_rules, dict):
        raise ValidationError("Validation rules must be a dictionary")
    
    for field, rules in validation_rules.items():
        if isinstance(data, dict):
            value = data.get(field)
        else:
            value = getattr(data, field, None)
        
        # Check required fields
        if rules.get('required', False) and value is None:
            raise ValidationError(f"Field '{field}' is required", field=field, value=value)
        
        # Check data type
        if 'type' in rules and value is not None:
            expected_type = rules['type']
            if not isinstance(value, expected_type):
                raise ValidationError(
                    f"Field '{field}' must be of type {expected_type.__name__}, got {type(value).__name__}",
                    field=field, 
                    value=value
                )
        
        # Check value range for numbers
        if 'min_value' in rules and isinstance(value, (int, float)):
            if value < rules['min_value']:
                raise ValidationError(
                    f"Field '{field}' must be >= {rules['min_value']}, got {value}",
                    field=field,
                    value=value
                )
        
        if 'max_value' in rules and isinstance(value, (int, float)):
            if value > rules['max_value']:
                raise ValidationError(
                    f"Field '{field}' must be <= {rules['max_value']}, got {value}",
                    field=field,
                    value=value
                )
        
        # Check string length
        if 'min_length' in rules and isinstance(value, str):
            if len(value) < rules['min_length']:
                raise ValidationError(
                    f"Field '{field}' must be at least {rules['min_length']} characters",
                    field=field,
                    value=value
                )
        
        if 'max_length' in rules and isinstance(value, str):
            if len(value) > rules['max_length']:
                raise ValidationError(
                    f"Field '{field}' must be at most {rules['max_length']} characters",
                    field=field,
                    value=value
                )
    
    return True


def format_error_response(error: Exception) -> Dict:
    """
    Format an error into a standardized response
    
    Args:
        error: Exception to format
        
    Returns:
        Dict: Formatted error response
    """
    if isinstance(error, (DataError, ValidationError, ProcessingError)):
        return {
            "success": False,
            "error_type": error.__class__.__name__,
            "message": error.message,
            "details": getattr(error, 'details', {}),
            "field": getattr(error, 'field', None),
            "error_code": getattr(error, 'error_code', None)
        }
    else:
        return {
            "success": False,
            "error_type": "UnexpectedError",
            "message": str(error),
            "details": {}
        }


def retry_on_failure(max_retries: int = 3, delay: float = 1.0, exceptions: tuple = (Exception,)):
    """
    Decorator to retry function execution on failure
    
    Args:
        max_retries: Maximum number of retry attempts
        delay: Delay between retries in seconds
        exceptions: Tuple of exceptions to catch and retry on
        
    Returns:
        Decorator function
    """
    def decorator(func: Callable) -> Callable:
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            import time
            
            last_exception = None
            for attempt in range(max_retries + 1):
                try:
                    return func(*args, **kwargs)
                except exceptions as e:
                    last_exception = e
                    if attempt < max_retries:
                        log_warning(f"Attempt {attempt + 1} failed for {func.__name__}: {str(e)}. Retrying in {delay}s...")
                        time.sleep(delay)
                    else:
                        log_error(f"All {max_retries + 1} attempts failed for {func.__name__}", error=e)
            
            raise last_exception
        
        return wrapper
    return decorator


# Context manager for error handling
class ErrorHandler:
    """Context manager for comprehensive error handling"""
    
    def __init__(self, operation_name: str, raise_on_error: bool = True):
        self.operation_name = operation_name
        self.raise_on_error = raise_on_error
        self.error = None
        
    def __enter__(self):
        return self
        
    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type is not None:
            self.error = exc_val
            log_error(f"Error in {self.operation_name}: {str(exc_val)}", error=exc_val)
            
            if not self.raise_on_error:
                return True  # Suppress the exception
        
        return False  # Let the exception propagate