"""Typed exceptions raised by user-engine services."""

from __future__ import annotations


class UserEngineError(Exception):
    """Base class for user-engine failures."""


class AuthorizationDenied(UserEngineError):
    """Raised when the authorization port denies an operation."""


class ConflictError(UserEngineError):
    """Raised when a write would violate a uniqueness constraint."""


class NotFoundError(UserEngineError):
    """Raised when a requested domain object does not exist."""


class ValidationError(UserEngineError):
    """Raised when input fails domain validation."""