import json
from collections import UserDict
import os
import sys
from . import data

class SettingsLoader(UserDict):
    def __init__(self: object, file: str) -> None:
        self.data = {}
        self.load_settings_file(file)

    def load_settings_file(self: object, file: str) -> None:
        ext = os.path.splitext(file)[1]
        with data.data_open('conf', file) as fd:
            if ext == '.json':
                self.data.update(json.load(fd))
            else:
                raise ValueError("Cannot open this type of settings file")

class SettingsReadOnly(SettingsLoader):
    pass

class SettingsMutable(SettingsLoader):
    pass

class SettingsWritable(SettingsMutable):
    pass

init = SettingsWritable('init.json')