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#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
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# distributed under the License is distributed on an "AS IS" BASIS,
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"""Tools for representing JavaScript code in BSON."""
from __future__ import annotations

from collections.abc import Mapping as _Mapping
from typing import Any, Mapping, Optional, Type, Union


class Code(str):
    """BSON's JavaScript code type.

    Raises :class:`TypeError` if `code` is not an instance of
    :class:`str` or `scope` is not ``None`` or an instance
    of :class:`dict`.

    Scope variables can be set by passing a dictionary as the `scope`
    argument or by using keyword arguments. If a variable is set as a
    keyword argument it will override any setting for that variable in
    the `scope` dictionary.

    :Parameters:
      - `code`: A string containing JavaScript code to be evaluated or another
        instance of Code. In the latter case, the scope of `code` becomes this
        Code's :attr:`scope`.
      - `scope` (optional): dictionary representing the scope in which
        `code` should be evaluated - a mapping from identifiers (as
        strings) to values. Defaults to ``None``. This is applied after any
        scope associated with a given `code` above.
      - `**kwargs` (optional): scope variables can also be passed as
        keyword arguments. These are applied after `scope` and `code`.

    .. versionchanged:: 3.4
      The default value for :attr:`scope` is ``None`` instead of ``{}``.

    """

    _type_marker = 13
    __scope: Union[Mapping[str, Any], None]

    def __new__(
        cls: Type[Code],
        code: Union[str, Code],
        scope: Optional[Mapping[str, Any]] = None,
        **kwargs: Any,
    ) -> Code:
        if not isinstance(code, str):
            raise TypeError("code must be an instance of str")

        self = str.__new__(cls, code)

        try:
            self.__scope = code.scope  # type: ignore
        except AttributeError:
            self.__scope = None

        if scope is not None:
            if not isinstance(scope, _Mapping):
                raise TypeError("scope must be an instance of dict")
            if self.__scope is not None:
                self.__scope.update(scope)  # type: ignore
            else:
                self.__scope = scope

        if kwargs:
            if self.__scope is not None:
                self.__scope.update(kwargs)  # type: ignore
            else:
                self.__scope = kwargs

        return self

    @property
    def scope(self) -> Optional[Mapping[str, Any]]:
        """Scope dictionary for this instance or ``None``."""
        return self.__scope

    def __repr__(self) -> str:
        return f"Code({str.__repr__(self)}, {self.__scope!r})"

    def __eq__(self, other: Any) -> bool:
        if isinstance(other, Code):
            return (self.__scope, str(self)) == (other.__scope, str(other))
        return False

    __hash__: Any = None

    def __ne__(self, other: Any) -> bool:
        return not self == other
