JsonSerializable

import dataclasses
import inspect
from pathlib import Path
import json


class JsonSerializable:
    @classmethod
    def from_json(cls, path: Path | str, post_init_setattr: bool = False):
        """
        Loads a JSON file and creates an object with loaded data.

        Works fine with typing.NamedTuple / typing.TypedDict / dataclasses.dataclass.

        The object's `__init__` method must accept ALL the object attributes as keyword-possible arguments.
         """

        if cls == JsonSerializable:
            raise TypeError('Cannot load to JsonSerializable itself.'
                            ' Maybe you want to inherit your class from JsonSerializable to load from JSON?')

        with open(path) as f:
            attrs = json.load(f)
            if not post_init_setattr:
                return cls(**attrs)

            sig = inspect.signature(cls.__init__)
            init_attrs = {k: v for k, v in attrs.items() if sig.parameters.get(k)}
            other_attrs = dict(set(attrs.items()) - set(init_attrs.items()))

            obj = cls(**init_attrs)
            for name, value in other_attrs.items():
                setattr(obj, name, value)
            return obj

    def to_json(self, path: Path | str):
        """
        Saves the object attributes to JSON file.

        Be aware that ALL the attributes will be saved.

        Works fine with typing.NamedTuple / typing.TypedDict / dataclasses.dataclass.
        """
        if self.__class__ == JsonSerializable:
            raise TypeError('Cannot save from JsonSerializable itself.'
                            ' Maybe you want to inherit your class from JsonSerializable to save to JSON?')

        with open(path, 'w+') as f:
            json.dump(vars(self), f)


def main():
    # example class
    @dataclasses.dataclass
    class Data(JsonSerializable):
        field1: int
        field2: float
        field3: str

    # loading
    data = Data.from_json('initial.json')
    # doing some data manipulations
    assert data.field3 == 'pending', f'Expected "pending" status, got {data.field3}'
    data.field1 = int(data.field2 % 3)
    data.field2 = .0
    data.field3 = 'success'
    # saving
    data.to_json('result.json')


if __name__ == '__main__':
    main()