src/core/exceptions.py

"""
Custom Exception Classes for Production Error Handling
"""

from typing import Any, Dict, Optional
from fastapi import status


class AppException(Exception):
    """Base application exception"""
    
    def __init__(
        self,
        message: str,
        status_code: int = status.HTTP_500_INTERNAL_SERVER_ERROR,
        details: Optional[Dict[str, Any]] = None
    ):
        self.message = message
        self.status_code = status_code
        self.details = details or {}
        super().__init__(self.message)


class ValidationError(AppException):
    """Validation error exception"""
    
    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None):
        super().__init__(
            message=message,
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            details=details
        )


class AuthenticationError(AppException):
    """Authentication error exception"""
    
    def __init__(self, message: str = "Authentication failed"):
        super().__init__(
            message=message,
            status_code=status.HTTP_401_UNAUTHORIZED,
            details={"www_authenticate": "Bearer"}
        )


class AuthorizationError(AppException):
    """Authorization error exception"""
    
    def __init__(self, message: str = "Insufficient permissions"):
        super().__init__(
            message=message,
            status_code=status.HTTP_403_FORBIDDEN
        )


class ResourceNotFoundError(AppException):
    """Resource not found exception"""
    
    def __init__(self, resource: str, identifier: Any):
        super().__init__(
            message=f"{resource} not found",
            status_code=status.HTTP_404_NOT_FOUND,
            details={"resource": resource, "identifier": str(identifier)}
        )


class RateLimitExceededError(AppException):
    """Rate limit exceeded exception"""
    
    def __init__(self, limit: int, window: str):
        super().__init__(
            message=f"Rate limit exceeded: {limit} requests per {window}",
            status_code=status.HTTP_429_TOO_MANY_REQUESTS,
            details={"limit": limit, "window": window}
        )


class ModelLoadError(AppException):
    """ML model loading error"""
    
    def __init__(self, model_name: str, reason: str):
        super().__init__(
            message=f"Failed to load model: {model_name}",
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            details={"model": model_name, "reason": reason}
        )


class PredictionError(AppException):
    """ML prediction error"""
    
    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None):
        super().__init__(
            message=message,
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            details=details
        )


class FileUploadError(AppException):
    """File upload error"""
    
    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None):
        super().__init__(
            message=message,
            status_code=status.HTTP_400_BAD_REQUEST,
            details=details
        )


class DatabaseError(AppException):
    """Database operation error"""
    
    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None):
        super().__init__(
            message=message,
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            details=details
        )


class CacheError(AppException):
    """Cache operation error"""
    
    def __init__(self, message: str, details: Optional[Dict[str, Any]] = None):
        super().__init__(
            message=message,
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            details=details
        )