class HaystackError(Exception):
    """A generic exception for all others to extend."""

    pass


class SearchBackendError(HaystackError):
    """Raised when a backend can not be found."""

    pass


class SearchFieldError(HaystackError):
    """Raised when a field encounters an error."""

    pass


class MissingDependency(HaystackError):
    """Raised when a library a backend depends on can not be found."""

    pass


class NotHandled(HaystackError):
    """Raised when a model is not handled by the router setup."""

    pass


class MoreLikeThisError(HaystackError):
    """Raised when a model instance has not been provided for More Like This."""

    pass


class FacetingError(HaystackError):
    """Raised when incorrect arguments have been provided for faceting."""

    pass


class SpatialError(HaystackError):
    """Raised when incorrect arguments have been provided for spatial."""

    pass


class StatsError(HaystackError):
    "Raised when incorrect arguments have been provided for stats"
    pass


class SkipDocument(HaystackError):
    """Raised when a document should be skipped while updating"""

    pass