#-----------------------------------------------------------------------------
# Copyright (c) Anaconda, Inc., and Bokeh Contributors.
# All rights reserved.
#
# The full license is in the file LICENSE.txt, distributed with this software.
#-----------------------------------------------------------------------------
""" Provide the dataclass property.
"""

#-----------------------------------------------------------------------------
# Boilerplate
#-----------------------------------------------------------------------------
from __future__ import annotations

import logging # isort:skip
log = logging.getLogger(__name__)

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------

# Standard library imports
from dataclasses import is_dataclass
from typing import Any, TypeVar

# Bokeh imports
from .bases import Property

#-----------------------------------------------------------------------------
# Globals and constants
#-----------------------------------------------------------------------------

__all__ = (
    'Dataclass',
)

T = TypeVar("T", bound=object)

#-----------------------------------------------------------------------------
# General API
#-----------------------------------------------------------------------------

class Dataclass(Property[T]):
    """ Accept instance of dataclass.

    This property only exists to support type validation, e.g. for "accepts"
    clauses. It is not serializable itself, and is not useful to add to
    Bokeh models directly.

    """
    def validate(self, value: Any, detail: bool = True) -> None:
        super().validate(value, detail)
        if is_dataclass(value) and not isinstance(value, type):
            return

        msg = "" if not detail else f"expected object to be dataclass, got {value!r}"
        raise ValueError(msg)

#-----------------------------------------------------------------------------
# Dev API
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#-----------------------------------------------------------------------------
# Private API
#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Code
#-----------------------------------------------------------------------------