"""Custom exception classes for the AI Services V2 layer."""


class DatasetError(Exception):
    """Raised when dataset operations fail (missing file, schema mismatch)."""


class TrainingError(Exception):
    """Raised when a model training pipeline fails.

    Attributes:
        model_name: The name of the model whose training failed.
        message: Human-readable description of the failure.
    """

    def __init__(self, message: str, model_name: str) -> None:
        self.model_name = model_name
        super().__init__(f"[{model_name}] {message}")


class ModelNotLoadedError(Exception):
    """Raised when inference is attempted on an unloaded model."""


class EntityNotFoundError(Exception):
    """Raised when a referenced entity (student, LO, class) doesn't exist."""