class DomainError(Exception):
    """Base domain error."""

class EntityNotFoundError(DomainError):
    def __init__(self, entity_type: str, entity_id: str):
        super().__init__(f"{entity_type} not found: {entity_id}")
        self.entity_type = entity_type
        self.entity_id = entity_id

class ValidationError(DomainError):
    def __init__(self, message: str, field: str | None = None):
        super().__init__(message)
        self.field = field

class FileParsingError(DomainError):
    pass

class ExportError(DomainError):
    pass

class ServiceCommunicationError(DomainError):
    def __init__(self, service_name: str, message: str):
        super().__init__(f"Error communicating with {service_name}: {message}")
        self.service_name = service_name